Home » Public Forums » GMCnet » Help me understand vapor lock
| Help me understand vapor lock [message #209388] |
Fri, 31 May 2013 07:55  |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
|
Senior Member |
|
|
I've been following Ken Henderson and Dennis' blog of their trip out west and was sad to read that Ken had some vapor lock problems a couple times and some serious problems coming up out of Death Valley.
Ken's coach is what I consider a PERFECT GMC. He's done everything to a very high degree of mechanical perfection and has EFI on the CADDY. If he's having vapor lock issues it doesn't bode well for my stock carb if we make the Route 66 run next summer.
I understand that vapor lock happens when gas boils in the lines or carb. But since Ken has EFI, I assume it's boiling in the lines. And since I'm pretty sure that Ken's fuel pump is back by the tanks and is a 'pusher', does that mean it is boiling BEFORE the pump or can it still boil after the pump when it's under pressure? Or is it actually boiling between the tank and the pump? I have a hard time imagining that it is boiling INSIDE the tank????
Has anyone tried having a small fuel cell INSIDE the air conditioned space of the cab to keep a few gallons cool before being pumped to the fuel system?
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
|
|
|
|
| Re: Help me understand vapor lock [message #209390 is a reply to message #209388] |
Fri, 31 May 2013 09:00  |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
|
Senior Member |
|
|
I don't like the idea of having any fuel within the passenger compartment. When I read about people moving GMC's by using a marine gas tank with the hatch open frankly scares the heck out of me. Just my personal aversion to fire. I do have the scars to prove it.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
|
|
|
|
| Re: Help me understand vapor lock [message #209393 is a reply to message #209390] |
Fri, 31 May 2013 09:09 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
|
Senior Member |
|
|
| tphipps wrote on Fri, 31 May 2013 09:00 |
I don't like the idea of having any fuel within the passenger compartment. ...
|
I don't either Tom. BUT, if it helps, there are ways to isolate and insulate a fuel CELL that could be cooled by the AC system and still be kept OUTSIDE the passenger compartment. The question is, would it help?
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
|
|
|
|
| Re: [GMCnet] Help me understand vapor lock [message #209394 is a reply to message #209388] |
Fri, 31 May 2013 09:05 |
Jp Benson
Messages: 649
Registered: October 2011
Location: Fla
Karma: 2
|
Senior Member |
|
|
GMC vendors sell an insulated version of the tube that goes from the mechanical pump to the carb. It's supposed to reduce vaporlock. So engine heat is the culprit in this scenario. It would be useful to instrument the fuel line at various points to see how fuel temperature changes.
Would avoid gasoline in A/C space for obvious safety reasons. Just a wild idea but how about a fuel line mounted cooler.
JP
>________________________________
> From: Kerry Pinkerton <Pinkertonk@MCHSI.com>
>To: gmclist@temp.gmcnet.org
>Sent: Friday, May 31, 2013 8:56 AM
>Subject: [GMCnet] Help me understand vapor lock
>
>
>
>
>I've been following Ken Henderson and Dennis' blog of their trip out west and was sad to read that Ken had some vapor lock problems a couple times and some serious problems coming up out of Death Valley.
>
>Ken's coach is what I consider a PERFECT GMC. He's done everything to a very high degree of mechanical perfection and has EFI on the CADDY. If he's having vapor lock issues it doesn't bode well for my stock carb if we make the Route 66 run next summer.
>
>I understand that vapor lock happens when gas boils in the lines or carb. But since Ken has EFI, I assume it's boiling in the lines. And since I'm pretty sure that Ken's fuel pump is back by the tanks and is a 'pusher', does that mean it is boiling BEFORE the pump or can it still boil after the pump when it's under pressure? Or is it actually boiling between the tank and the pump? I have a hard time imagining that it is boiling INSIDE the tank????
>
>Has anyone tried having a small fuel cell INSIDE the air conditioned space of the cab to keep a few gallons cool before being pumped to the fuel system?
>--
>Kerry Pinkerton
>
>North Alabama, near Huntsville,
>
>77 Eleganza II, "The Lady", 403CI, also a 76 Eleganza being re-bodied as an Art Deco car hauler
>_______________________________________________
>GMCnet mailing list
>Unsubscribe or Change List Options:
>http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
>
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
| Re: [GMCnet] Help me understand vapor lock [message #209409 is a reply to message #209393] |
Fri, 31 May 2013 10:13 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
|
Senior Member |
|
|
Vapor lock, what it is and isn't. It starts with tiny bubbles, kinda like
champagne bubbles, in the liquid fuel system. These bubbles occur because
some of the hydrocarbon components of modern motor fuels are lighter than
air at 120 -150 degrees farenheit, and try to exit the fuel stream. When
this occurs the fuel bubbles (boils) . If this occurs in the fuel lines or
tanks, large amounts of expansion occurs. When even the best high pressure
fuel pumps encounter bubbles in the fuel, all they do is compress the
bubbles, NOT MOVE THE FUEL THROUGH THE LINES!!! That is when the operator
notices a lack of throttle response and bogging when throttle is applied.
How do we fix it?? The fix is in the FUEL, not the Gmc. Take the ethanol
out of the FUEL. Raise the Reid Vapour Index of the FUEL. How likely is
that happening soon? Not very. So, now what? Drive in the cool part of the
day helps. Electric "pusher type" fuel pumps help. Keeping your fuel tanks
full helps. Blocked exhaust crossovers helps. Lower engine compartment
temperature helps. But nothing we try will TOTALLY SOLVE vapor lock. Just
my experienced opinion.
Jim Hupy
Salem,Or
78 Gmc Royale 403
On May 31, 2013 7:09 AM, "Kerry Pinkerton" <Pinkertonk@mchsi.com> wrote:
>
>
> tphipps wrote on Fri, 31 May 2013 09:00
> > I don't like the idea of having any fuel within the passenger
> compartment. ...
>
>
> I don't either Tom. BUT, if it helps, there are ways to isolate and
> insulate a fuel CELL that could be cooled by the AC system and still be
> kept OUTSIDE the passenger compartment. The question is, would it help?
> --
> Kerry Pinkerton
>
> North Alabama, near Huntsville,
>
> 77 Eleganza II, "The Lady", 403CI, also a 76 Eleganza being re-bodied as
> an Art Deco car hauler
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
| Re: Help me understand vapor lock [message #209410 is a reply to message #209388] |
Fri, 31 May 2013 10:32 |
GeorgeRud
Messages: 1380
Registered: February 2007
Location: Chicago, IL
Karma: 0
|
Senior Member |
|
|
I think James hit the nail on the head- it's today's fuels, but we're stuck with what we can get!
I think anything that can help cool the fuel would be beneficial, but not inside the coach. I sometimes wonder if running the fuel lines on the outside of the chassis rail (for more air flow) would help, but having the actual temperatures of the fuel along it's path from the tank to the carb would probably help determine where the problem is the greatest.
George Rudawsky
Chicago, IL
75 Palm Beach
|
|
|
|
|
|
| Re: [GMCnet] Help me understand vapor lock [message #209414 is a reply to message #209410] |
Fri, 31 May 2013 11:03 |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
|
Senior Member |
|
|
George - I had my steel fuel lines outside the frame rail for several years and it did not stop the occasional vapor lock.
As I pointed out in another email, the problem is the greatest between the fuel tank and the pump. I struggled with this problem for several years and tried insulating the lines, moving them from in front of the GMC frame below the radiator to coming up to the rear of the throtttle body (TBI system) near the brake combination valve, using larger diameter lines, etc. Nothing seemed to make much difference until I eliminated having any fuel line between the tanks and the pump by putting the pumps into the tanks.
Most modern autos and trucks have in-tank fuel pumps and we don't hear much about vapor lock problems with them even with the use of ethanol laced gasoline.
Emery Stora
77 Kingsley
Frederick, CO
On May 31, 2013, at 9:32 AM, George Rudawsky wrote:
>
>
> I think James hit the nail on the head- it's today's fuels, but we're stuck with what we can get!
>
> I think anything that can help cool the fuel would be beneficial, but not inside the coach. I sometimes wonder if running the fuel lines on the outside of the chassis rail (for more air flow) would help, but having the actual temperatures of the fuel along it's path from the tank to the carb would probably help determine where the problem is the greatest.
> --
> George Rudawsky
> Chicago, IL
> 75 Palm Beach
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
| Re: [GMCnet] Help me understand vapor lock [message #209421 is a reply to message #209414] |
Fri, 31 May 2013 11:58 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
|
Senior Member |
|
|
I have done everything BUT install in tank fuel pumps in an effort to cure vapor lock. I have; installed a heat dissipator under the carb, installed Jim B's insulated, braded fuel line from fuel pump to carb, installed a cold air intake from the grille to the air cleaner, installed an electric fuel pump right back at the tank on the aux tank, installed a Gary Rockwell intake manifold, installed a severe duty fan clutch, etc, etc. I STILL have vapor lock on occasion when the temps are above 90 and I am climbing or otherwise putting the engine under extreme load. The closest thing to a cure has been the electric fuel pump.
On our recent trip to Texas, we drove from Tucson to Las Cruces, about 280 miles, in the late afternoon and evening. Not much trouble then, but I did have to turn on the electric pump several times. Hal Told us where an ethanol free station was in town and we filled up there for the next leg of the trip, bypassing El Paso on the north side and proceeding to Carlsbad Caverns. There are several good climbs along that route, including the Guadalupe Mountains. For the first time since I got the coach, I had NO vapor lock issues whatsoever. I turned on the electric pump while pulling the grade up the Guadalupe mountains as a precaution, but probably would not have needed it.
James is right, the best cure for vapor lock is ethanol free gasoline. Since that doesn't seem like a viable option in most parts of the country, Emery's in tank fuel pump option would seem the be a good alternative as well.
By the way, I gassed up in Las Cruces on the way home, at the same e-free station, and had considerably more gas in the tanks when hen I got home that I did covering the same ground on the way TO las Cruces. The coach also had noticeably more power on the e-free gas.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
|
|
|
|
| Re: [GMCnet] Help me understand vapor lock [message #209425 is a reply to message #209421] |
Fri, 31 May 2013 13:16 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
|
Senior Member |
|
|
pure-gas.org is Your Friend. I can usually make a trip on gasoline, and when I do, I have no problems and an extra 1 mpg (that's a ten percent increase). The biggest problem I have is a trip to San Antonio most years in mid - July. Out og Houston, there's no gas to be had. Go figure. I have to make the foirst part of the homebound trip eaerly in the morning, and get to East Tejas before it gets too hot. Even then, it will lock and die when stopped. Moving, it survives.
--johnny
'76b 23' transmode norris
'76 palm beach
________________________________
From: Carl Stouffer <carljr3b@yahoo.com>
To: gmclist@temp.gmcnet.org
Sent: Friday, May 31, 2013 12:58 PM
Subject: Re: [GMCnet] Help me understand vapor lock
I have done everything BUT install in tank fuel pumps in an effort to cure vapor lock. I have; installed a heat dissipator under the carb, installed Jim B's insulated, braded fuel line from fuel pump to carb, installed a cold air intake from the grille to the air cleaner, installed an electric fuel pump right back at the tank on the aux tank, installed a Gary Rockwell intake manifold, installed a severe duty fan clutch, etc, etc. I STILL have vapor lock on occasion when the temps are above 90 and I am climbing or otherwise putting the engine under extreme load. The closest thing to a cure has been the electric fuel pump.
On our recent trip to Texas, we drove from Tucson to Las Cruces, about 280 miles, in the late afternoon and evening. Not much trouble then, but I did have to turn on the electric pump several times. Hal Told us where an ethanol free station was in town and we filled up there for the next leg of the trip, bypassing El Paso on the north side and proceeding to Carlsbad Caverns. There are several good climbs along that route, including the Guadalupe Mountains. For the first time since I got the coach, I had NO vapor lock issues whatsoever. I turned on the electric pump while pulling the grade up the Guadalupe mountains as a precaution, but probably would not have needed it.
James is right, the best cure for vapor lock is ethanol free gasoline. Since that doesn't seem like a viable option in most parts of the country, Emery's in tank fuel pump option would seem the be a good alternative as well.
By the way, I gassed up in Las Cruces on the way home, at the same e-free station, and had considerably more gas in the tanks when hen I got home that I did covering the same ground on the way TO las Cruces. The coach also had noticeably more power on the e-free gas.
--
Carl S.
'75 ex Palm Beach
Tucson, AZ.
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
|
|
|
|
| Re: [GMCnet] Help me understand vapor lock [message #209432 is a reply to message #209425] |
Fri, 31 May 2013 13:41 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
|
Senior Member |
|
|
| Johnny Bridges wrote on Fri, 31 May 2013 11:16 |
pure-gas.org is Your Friend. I can usually make a trip on gasoline, and when I do, I have no problems and an extra 1 mpg (that's a ten percent increase). The biggest problem I have is a trip to San Antonio most years in mid - July. Out og Houston, there's no gas to be had. Go figure. I have to make the foirst part of the homebound trip eaerly in the morning, and get to East Tejas before it gets too hot. Even then, it will lock and die when stopped. Moving, it survives.
--johnny
'76b 23' transmode norris
'76 palm beach
________________________________
From: Carl Stouffer <carljr3b@yahoo.com>
To: gmclist@temp.gmcnet.org
Sent: Friday, May 31, 2013 12:58 PM
Subject: Re: [GMCnet] Help me understand vapor lock
I have done everything BUT install in tank fuel pumps in an effort to cure vapor lock. I have; installed a heat dissipator under the carb, installed Jim B's insulated, braded fuel line from fuel pump to carb, installed a cold air intake from the grille to the air cleaner, installed an electric fuel pump right back at the tank on the aux tank, installed a Gary Rockwell intake manifold, installed a severe duty fan clutch, etc, etc. I STILL have vapor lock on occasion when the temps are above 90 and I am climbing or otherwise putting the engine under extreme load. The closest thing to a cure has been the electric fuel pump.
On our recent trip to Texas, we drove from Tucson to Las Cruces, about 280 miles, in the late afternoon and evening. Not much trouble then, but I did have to turn on the electric pump several times. Hal Told us where an ethanol free station was in town and we filled up there for the next leg of the trip, bypassing El Paso on the north side and proceeding to Carlsbad Caverns. There are several good climbs along that route, including the Guadalupe Mountains. For the first time since I got the coach, I had NO vapor lock issues whatsoever. I turned on the electric pump while pulling the grade up the Guadalupe mountains as a precaution, but probably would not have needed it.
James is right, the best cure for vapor lock is ethanol free gasoline. Since that doesn't seem like a viable option in most parts of the country, Emery's in tank fuel pump option would seem the be a good alternative as well.
By the way, I gassed up in Las Cruces on the way home, at the same e-free station, and had considerably more gas in the tanks when hen I got home that I did covering the same ground on the way TO las Cruces. The coach also had noticeably more power on the e-free gas.
--
Carl S.
'75 ex Palm Beach
Tucson, AZ.
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
Yes, I refer to Puregas.org all the time. Take a look at their listing for AZ, NM, and West TX, as well as CA, NV, and UT.
E-free gas is hard to come by in those areas. It is often only available at airports and marinas. I also got some (that was reported as e-free anyway) at White's City, NM, just outside of Carlsbad Caverns. It was not to be had for most of the rest of the trip (to San Antonio).
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
|
|
|
|
|
|
| Re: [GMCnet] Help me understand vapor lock [message #209462 is a reply to message #209425] |
Fri, 31 May 2013 18:49 |
 |
hnielsen2
Messages: 1434
Registered: February 2004
Location: Alpine CA
Karma: 0
|
Senior Member |
|
|
Talked about this before.
I installed aluminum diamond plate under the tanks with a kick up on the leading edge.
It's attached to the frame with self tapping screws.
Works excepted on the VERY hottest of days with the black top at over 100 degrees at altitude over 4,000 feet.
We are fighting junk gas, hot pavement and altitude.
I received a news letter today from S E M A we will have E-15 by the year 2022 unless we stop it.
We all need to back bills H.R. 875 and S 344 bought supported by S E M A.
Get after your local lawmakers.
This year Florida, Maine, West Virginia and Oregon have taken the lead in dealing with the ethanol issue.
Give them an "att'a boy or girl" for putting the brakes on ethanol in our fuel
Sorry I do not have photos of the diamond plate our GMC
Thanks
Howard
All is well with my Lord
On May 31, 2013, at 11:16 AM, Johnny Bridges <jhbridges@ymail.com> wrote:
> pure-gas.org is Your Friend. I can usually make a trip on gasoline, and when I do, I have no problems and an extra 1 mpg (that's a ten percent increase). The biggest problem I have is a trip to San Antonio most years in mid - July. Out og Houston, there's no gas to be had. Go figure. I have to make the foirst part of the homebound trip eaerly in the morning, and get to East Tejas before it gets too hot. Even then, it will lock and die when stopped. Moving, it survives.
>
> --johnny
> '76b 23' transmode norris
> '76 palm beach
>
>
> ________________________________
> From: Carl Stouffer <carljr3b@yahoo.com>
> To: gmclist@temp.gmcnet.org
> Sent: Friday, May 31, 2013 12:58 PM
> Subject: Re: [GMCnet] Help me understand vapor lock
>
>
>
>
> I have done everything BUT install in tank fuel pumps in an effort to cure vapor lock. I have; installed a heat dissipator under the carb, installed Jim B's insulated, braded fuel line from fuel pump to carb, installed a cold air intake from the grille to the air cleaner, installed an electric fuel pump right back at the tank on the aux tank, installed a Gary Rockwell intake manifold, installed a severe duty fan clutch, etc, etc. I STILL have vapor lock on occasion when the temps are above 90 and I am climbing or otherwise putting the engine under extreme load. The closest thing to a cure has been the electric fuel pump.
>
> On our recent trip to Texas, we drove from Tucson to Las Cruces, about 280 miles, in the late afternoon and evening. Not much trouble then, but I did have to turn on the electric pump several times. Hal Told us where an ethanol free station was in town and we filled up there for the next leg of the trip, bypassing El Paso on the north side and proceeding to Carlsbad Caverns. There are several good climbs along that route, including the Guadalupe Mountains. For the first time since I got the coach, I had NO vapor lock issues whatsoever. I turned on the electric pump while pulling the grade up the Guadalupe mountains as a precaution, but probably would not have needed it.
>
> James is right, the best cure for vapor lock is ethanol free gasoline. Since that doesn't seem like a viable option in most parts of the country, Emery's in tank fuel pump option would seem the be a good alternative as well.
>
> By the way, I gassed up in Las Cruces on the way home, at the same e-free station, and had considerably more gas in the tanks when hen I got home that I did covering the same ground on the way TO las Cruces. The coach also had noticeably more power on the e-free gas.
> --
> Carl S.
> '75 ex Palm Beach
> Tucson, AZ.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
All is well with my Lord
|
|
|
|
| Re: [GMCnet] Help me understand vapor lock [message #209485 is a reply to message #209388] |
Fri, 31 May 2013 22:23 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
I should supplement Dennis' explanation of our vapor lock problem: Shortly
before descending into Death Valley, in Amargosa Valley (formerly Lathrop
Wells), NV, we filled up with gas. Within a few miles, the engine stumbled
a little, but at the 5000' or so altitude we'd reached, I didn't think much
about it -- I don't think it persisted long enough for me to even switch
tanks (and "pusher" pumps).
In the valley, the engine ran fine during our 60 mile detour to the "lowest
spot in the US" and until we started climbing out of the valley toward the
west. Even with the temperature at 99*F, I was surprised at the engine
stumbling even before we climbed back to sea level. When switching tanks
didn't help, I was really surprised. By the time we reached 2000' MSL, the
engine would hardly run and the fuel pressure was dropping from 18 psi to
below 10 psi -- and even to 4 psi! That's when we found a wide shoulder
and stopped. With the sun shining on the coach, it was REALLY getting warm
for us, so we put the awning out and set up lawn chairs. After 45 minutes
or so, the wind picked up enough that we re-stowed the awning and moved
into the shade on the other side of the coach. We probably sat for 1-1/2
hours, until about 4 PM before trying again to climb out of that hell-hole.
We made it only 5 miles or so before the fuel pressure dropped again. This
time, Dennis loosened the gas cap and relieved quite a bit of pressure
before leaving the cap loosely installed. That helped for about 5 minutes
of travel, then we were beside the road again. For some reason, Dennis
checked the fuel cap again and found that all of the paint inside the
filler compartment was bubbled up and wrinkled. That was, to me, a sure
sign that the gasoline we'd bought was LOADED with ethanol. The paint
there had been similarly damaged several years ago, but during a much
longer period of time, and while the paint was very new -- and nowhere
nearly as badly as this time.
After several more unsuccessful attempts to move, we finally resorted to
disconnecting the toad. After another 1/2-3/4 hour cooling period, we
tried again. That time, with little load on the Cad500, and temperatures
beginning to decline toward desert nighttime levels, the fuel pressure
stayed up and I had no more trouble.
While we never actually heard boiling in the tanks, I'm confident that was
what was happening. Otherwise, I think one or the other of the Carter 4070
pumps on the outside of the left frame rail would have been able to push
enough gas into the surge tank beneath the driver's seat to have supplied
the high pressure pump. Either that, or the temperature of the surge tank
was so high that the fuel was boiling in it. I don't think that was
happening because the engine temperature only got above 220*F for a short
time, well into the problem. When I first installed the Cad, before the
aluminum radiator, I ran for quite a while above 250*F without any similar
symptoms.
We've had no more engine problems after that despite having been above
8000' MSL at least four times. We did disconnect the toad again for a
while climbing into Yosemite from the east, but that was mostly because
Dennis wanted the fun of mountain driving again -- he liked that better
than being bored (or terrified) in the passenger seat with me driving the
mountain roads (I didn't have the nerve to let him drive the GMC, with me
watching, there).
I can only attribute the problem to the gasoline. I wish I knew how to
prevent problems even in that situation, but I don't -- switching tanks had
absolutely no effect on the problem, so I'm convinced that in-tank pumps
would not have done much, if any, better.
I guess nighttime travel is the only solution. :-(
Ken H.
From JimK's parking lot in Newark, CA
On May 31, 2013 5:56 AM, "Kerry Pinkerton" wrote:
>
>
> I've been following Ken Henderson and Dennis' blog of their trip out west
> and was sad to read that Ken had some vapor lock problems a couple times
> and some serious problems coming up out of Death Valley.
>
...
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
|
|
|
|
| Re: [GMCnet] Help me understand vapor lock [message #209487 is a reply to message #209485] |
Fri, 31 May 2013 22:56 |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
|
Senior Member |
|
|
Ken,
Question about your surge tank. Is the surge tank under pressure from the rear fuel pumps or does it vent back to the tanks at atmospheric pressure? If it does that then you are also having a boiling issue in the surge tank also as the fuel goes from about 7psi back to atmospheric pressure causing a continuing fuel vapor pressure issue inside the surge tank. Could this be an issue?
JR
On May 31, 2013, at 11:23 PM, Ken Henderson <hend4800@bellsouth.net> wrote:
> I should supplement Dennis' explanation of our vapor lock problem: Shortly
> before descending into Death Valley, in Amargosa Valley (formerly Lathrop
> Wells), NV, we filled up with gas. Within a few miles, the engine stumbled
> a little, but at the 5000' or so altitude we'd reached, I didn't think much
> about it -- I don't think it persisted long enough for me to even switch
> tanks (and "pusher" pumps).
>
> In the valley, the engine ran fine during our 60 mile detour to the "lowest
> spot in the US" and until we started climbing out of the valley toward the
> west. Even with the temperature at 99*F, I was surprised at the engine
> stumbling even before we climbed back to sea level. When switching tanks
> didn't help, I was really surprised. By the time we reached 2000' MSL, the
> engine would hardly run and the fuel pressure was dropping from 18 psi to
> below 10 psi -- and even to 4 psi! That's when we found a wide shoulder
> and stopped. With the sun shining on the coach, it was REALLY getting warm
> for us, so we put the awning out and set up lawn chairs. After 45 minutes
> or so, the wind picked up enough that we re-stowed the awning and moved
> into the shade on the other side of the coach. We probably sat for 1-1/2
> hours, until about 4 PM before trying again to climb out of that hell-hole.
>
> We made it only 5 miles or so before the fuel pressure dropped again. This
> time, Dennis loosened the gas cap and relieved quite a bit of pressure
> before leaving the cap loosely installed. That helped for about 5 minutes
> of travel, then we were beside the road again. For some reason, Dennis
> checked the fuel cap again and found that all of the paint inside the
> filler compartment was bubbled up and wrinkled. That was, to me, a sure
> sign that the gasoline we'd bought was LOADED with ethanol. The paint
> there had been similarly damaged several years ago, but during a much
> longer period of time, and while the paint was very new -- and nowhere
> nearly as badly as this time.
>
> After several more unsuccessful attempts to move, we finally resorted to
> disconnecting the toad. After another 1/2-3/4 hour cooling period, we
> tried again. That time, with little load on the Cad500, and temperatures
> beginning to decline toward desert nighttime levels, the fuel pressure
> stayed up and I had no more trouble.
>
> While we never actually heard boiling in the tanks, I'm confident that was
> what was happening. Otherwise, I think one or the other of the Carter 4070
> pumps on the outside of the left frame rail would have been able to push
> enough gas into the surge tank beneath the driver's seat to have supplied
> the high pressure pump. Either that, or the temperature of the surge tank
> was so high that the fuel was boiling in it. I don't think that was
> happening because the engine temperature only got above 220*F for a short
> time, well into the problem. When I first installed the Cad, before the
> aluminum radiator, I ran for quite a while above 250*F without any similar
> symptoms.
>
> We've had no more engine problems after that despite having been above
> 8000' MSL at least four times. We did disconnect the toad again for a
> while climbing into Yosemite from the east, but that was mostly because
> Dennis wanted the fun of mountain driving again -- he liked that better
> than being bored (or terrified) in the passenger seat with me driving the
> mountain roads (I didn't have the nerve to let him drive the GMC, with me
> watching, there).
>
> I can only attribute the problem to the gasoline. I wish I knew how to
> prevent problems even in that situation, but I don't -- switching tanks had
> absolutely no effect on the problem, so I'm convinced that in-tank pumps
> would not have done much, if any, better.
>
> I guess nighttime travel is the only solution. :-(
>
> Ken H.
>
> From JimK's parking lot in Newark, CA
>
> On May 31, 2013 5:56 AM, "Kerry Pinkerton" wrote:
>
>>
>>
>> I've been following Ken Henderson and Dennis' blog of their trip out west
>> and was sad to read that Ken had some vapor lock problems a couple times
>> and some serious problems coming up out of Death Valley.
>>
> ...
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
|
|
|
|
| Re: [GMCnet] Help me understand vapor lock [message #209490 is a reply to message #209485] |
Fri, 31 May 2013 23:33 |
 |
ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
|
Senior Member |
|
|
Sounds like you got a tank of E85.
Larry Davick
On May 31, 2013, at 8:23 PM, Ken Henderson <hend4800@bellsouth.net> wrote:
> I should supplement Dennis' explanation of our vapor lock problem: Shortly
> before descending into Death Valley, in Amargosa Valley (formerly Lathrop
> Wells), NV, we filled up with gas. Within a few miles, the engine stumbled
> a little, but at the 5000' or so altitude we'd reached, I didn't think much
> about it -- I don't think it persisted long enough for me to even switch
> tanks (and "pusher" pumps).
>
> In the valley, the engine ran fine during our 60 mile detour to the "lowest
> spot in the US" and until we started climbing out of the valley toward the
> west. Even with the temperature at 99*F, I was surprised at the engine
> stumbling even before we climbed back to sea level. When switching tanks
> didn't help, I was really surprised. By the time we reached 2000' MSL, the
> engine would hardly run and the fuel pressure was dropping from 18 psi to
> below 10 psi -- and even to 4 psi! That's when we found a wide shoulder
> and stopped. With the sun shining on the coach, it was REALLY getting warm
> for us, so we put the awning out and set up lawn chairs. After 45 minutes
> or so, the wind picked up enough that we re-stowed the awning and moved
> into the shade on the other side of the coach. We probably sat for 1-1/2
> hours, until about 4 PM before trying again to climb out of that hell-hole.
>
> We made it only 5 miles or so before the fuel pressure dropped again. This
> time, Dennis loosened the gas cap and relieved quite a bit of pressure
> before leaving the cap loosely installed. That helped for about 5 minutes
> of travel, then we were beside the road again. For some reason, Dennis
> checked the fuel cap again and found that all of the paint inside the
> filler compartment was bubbled up and wrinkled. That was, to me, a sure
> sign that the gasoline we'd bought was LOADED with ethanol. The paint
> there had been similarly damaged several years ago, but during a much
> longer period of time, and while the paint was very new -- and nowhere
> nearly as badly as this time.
>
> After several more unsuccessful attempts to move, we finally resorted to
> disconnecting the toad. After another 1/2-3/4 hour cooling period, we
> tried again. That time, with little load on the Cad500, and temperatures
> beginning to decline toward desert nighttime levels, the fuel pressure
> stayed up and I had no more trouble.
>
> While we never actually heard boiling in the tanks, I'm confident that was
> what was happening. Otherwise, I think one or the other of the Carter 4070
> pumps on the outside of the left frame rail would have been able to push
> enough gas into the surge tank beneath the driver's seat to have supplied
> the high pressure pump. Either that, or the temperature of the surge tank
> was so high that the fuel was boiling in it. I don't think that was
> happening because the engine temperature only got above 220*F for a short
> time, well into the problem. When I first installed the Cad, before the
> aluminum radiator, I ran for quite a while above 250*F without any similar
> symptoms.
>
> We've had no more engine problems after that despite having been above
> 8000' MSL at least four times. We did disconnect the toad again for a
> while climbing into Yosemite from the east, but that was mostly because
> Dennis wanted the fun of mountain driving again -- he liked that better
> than being bored (or terrified) in the passenger seat with me driving the
> mountain roads (I didn't have the nerve to let him drive the GMC, with me
> watching, there).
>
> I can only attribute the problem to the gasoline. I wish I knew how to
> prevent problems even in that situation, but I don't -- switching tanks had
> absolutely no effect on the problem, so I'm convinced that in-tank pumps
> would not have done much, if any, better.
>
> I guess nighttime travel is the only solution. :-(
>
> Ken H.
>
> From JimK's parking lot in Newark, CA
>
> On May 31, 2013 5:56 AM, "Kerry Pinkerton" wrote:
>
>>
>>
>> I've been following Ken Henderson and Dennis' blog of their trip out west
>> and was sad to read that Ken had some vapor lock problems a couple times
>> and some serious problems coming up out of Death Valley.
>>
> ...
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
|
|
|
|
| Re: [GMCnet] Help me understand vapor lock [message #209502 is a reply to message #209413] |
Sat, 01 June 2013 02:12 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
|
Senior Member |
|
|
| emerystora wrote on Fri, 31 May 2013 08:56 |
On May 31, 2013, at 9:13 AM, James Hupy wrote:
> But nothing we try will TOTALLY SOLVE vapor lock. Just
> my experienced opinion.
> Jim Hupy
Jim
Have you tried to put in-tank fuel pumps into your tanks?
I did this about 5 years ago as I can say that it has indeed TOTALLY SOLVED any vapor lock problems for me.
I know that several others have now installed the in-tank fuel pumps. Perhaps they would like to share their experience. Have you had the same success that I have?
Emery Stora
77 Kingsley
Frederick, CO
|
While I don't have in tank pumps, Emrery is right. Here is my shade tree view.
1. Ethanol is here to stay. California has had it for years and years. After lead was eliminated it is an easy way to raise octane*
2. Cars started having Throttle Body fuel injection with pumps in the tank. This was 13-22 lbs of fuel pressure and ethanol does not boil at 13#s.
3. Cars started using port and combustion chamber injection with 42+ #s of pressure. E85 does not boil at 42#s of pressure.
4. Ken's vapor lock had to happen on the suction side. Lower pressure means lower temp to boil. Death valley should keep ethanol from boiling as soon in the tank. 8000 feet, not so much.
What I cannot understand is why I have not had vaporlock. We have had the coach in hot hot areas, high altitudes and so far, no problems. Of course I will probably be beside the road next week. Grin.
Another thing I cannot understand. If our tanks are boiling with ethanol, how can an E85 user ever open their gas cap? I know our tanks are flat and low, but these new rigs can get hot, too.
Question: can 13-22 lbs pumps be put in the tank and regulated down so a carburetor user can make this conversion?
* that doesn't mean more power from the fuel. Actually they can put ethanol in crummy gas and get the octane. Ethanol does not give more energy in fuel; it simply resists pre-ignition detonation. High octane does not necessairly mean more powerful fuel... It just has something tossed in to stop ping. Hotrodders used to inject water with alcohol added before the carb. This was the wave of the future in muscle car days.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
|
|
|
|
| Re: Help me understand vapor lock [message #209503 is a reply to message #209388] |
Sat, 01 June 2013 06:27 |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
|
Senior Member |
|
|
Well, try this on for size. We all know that vapor lock is a result of heating gas to the vapor point. Yet we continually run fuel from the tanks, up to the engine (where the fuel pressure regulator is, and where it is HOT) heat the gas up, and send it back to the tank. On top of that, many of us have insulated the tank so that while driving down the road, we can't even cool that heated gas. IIRC, most modern fuel systems have a dead headed system....fuel is pumped to a regulated pressure and heads up the lines for the injectors. The return occurs in the tank, or close to it, before heading to the motor. The pressure in the system, from tank to injectors, keeps the fuel from boiling, and the tank fuel is not heated because of hot fuel return.
These fuel pressurizing and return systems were designed in the 70's or 80's and used before 10% ethanol was mandated in many states.
So....what are the manufactures doing now that allows a E85 car to go into Death Valley at 110* and climb back out with out problems?
Part of the problem is US, pushing the limits of an old technology and then bitching when it does not work to our satisfaction. IMO the best solution is to avoid those marginal situations until we can design a modern fuel system that can handle this. I think we need to pressurize fuel at the tank, fuel only travels one way (to the motor only...no return) and insulate the tanks so that they cannot pickup heat from the roadway.
No offence intended...just what I think.
Larry 
78 Royale w/500 Caddy
Menomonie, WI.
|
|
|
|
| Re: [GMCnet] Help me understand vapor lock [message #209514 is a reply to message #209487] |
Sat, 01 June 2013 09:22 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
JR,
The surge tank has a 3/8" .return to the drain plug on the Aux tank. The
TB returns to the surge tank. I originally worried that perhaps, with the
#5 psi from the "pusher" I'd need a bigger return -- but previous
experience has not shown that to be true.
KenH
On May 31, 2013 8:56 PM, "John Wright" <powerjon@chartermi.net> wrote:
> Ken,
> Question about your surge tank. Is the surge tank under pressure from the
> rear fuel pumps or does it vent back to the tanks at atmospheric pressure?
> If it does that then you are also having a boiling issue in the surge tank
> also as the fuel goes from about 7psi back to atmospheric pressure causing
> a continuing fuel vapor pressure issue inside the surge tank. Could this
> be an issue?
>
> JR
> On May 31, 2013, at 11:23 PM, Ken Henderson <hend4800@bellsouth.net>
> wrote:
>
> > I should supplement Dennis' explanation of our vapor lock problem:
> Shortly
> > before descending into Death Valley, in Amargosa Valley (formerly Lathrop
> > Wells), NV, we filled up with gas. Within a few miles, the engine
> stumbled
> > a little, but at the 5000' or so altitude we'd reached, I didn't think
> much
> > about it -- I don't think it persisted long enough for me to even switch
> > tanks (and "pusher" pumps).
> >
> > In the valley, the engine ran fine during our 60 mile detour to the
> "lowest
> > spot in the US" and until we started climbing out of the valley toward
> the
> > west. Even with the temperature at 99*F, I was surprised at the engine
> > stumbling even before we climbed back to sea level. When switching tanks
> > didn't help, I was really surprised. By the time we reached 2000' MSL,
> the
> > engine would hardly run and the fuel pressure was dropping from 18 psi to
> > below 10 psi -- and even to 4 psi! That's when we found a wide shoulder
> > and stopped. With the sun shining on the coach, it was REALLY getting
> warm
> > for us, so we put the awning out and set up lawn chairs. After 45
> minutes
> > or so, the wind picked up enough that we re-stowed the awning and moved
> > into the shade on the other side of the coach. We probably sat for 1-1/2
> > hours, until about 4 PM before trying again to climb out of that
> hell-hole.
> >
> > We made it only 5 miles or so before the fuel pressure dropped again.
> This
> > time, Dennis loosened the gas cap and relieved quite a bit of pressure
> > before leaving the cap loosely installed. That helped for about 5
> minutes
> > of travel, then we were beside the road again. For some reason, Dennis
> > checked the fuel cap again and found that all of the paint inside the
> > filler compartment was bubbled up and wrinkled. That was, to me, a sure
> > sign that the gasoline we'd bought was LOADED with ethanol. The paint
> > there had been similarly damaged several years ago, but during a much
> > longer period of time, and while the paint was very new -- and nowhere
> > nearly as badly as this time.
> >
> > After several more unsuccessful attempts to move, we finally resorted to
> > disconnecting the toad. After another 1/2-3/4 hour cooling period, we
> > tried again. That time, with little load on the Cad500, and temperatures
> > beginning to decline toward desert nighttime levels, the fuel pressure
> > stayed up and I had no more trouble.
> >
> > While we never actually heard boiling in the tanks, I'm confident that
> was
> > what was happening. Otherwise, I think one or the other of the Carter
> 4070
> > pumps on the outside of the left frame rail would have been able to push
> > enough gas into the surge tank beneath the driver's seat to have supplied
> > the high pressure pump. Either that, or the temperature of the surge
> tank
> > was so high that the fuel was boiling in it. I don't think that was
> > happening because the engine temperature only got above 220*F for a short
> > time, well into the problem. When I first installed the Cad, before the
> > aluminum radiator, I ran for quite a while above 250*F without any
> similar
> > symptoms.
> >
> > We've had no more engine problems after that despite having been above
> > 8000' MSL at least four times. We did disconnect the toad again for a
> > while climbing into Yosemite from the east, but that was mostly because
> > Dennis wanted the fun of mountain driving again -- he liked that better
> > than being bored (or terrified) in the passenger seat with me driving the
> > mountain roads (I didn't have the nerve to let him drive the GMC, with me
> > watching, there).
> >
> > I can only attribute the problem to the gasoline. I wish I knew how to
> > prevent problems even in that situation, but I don't -- switching tanks
> had
> > absolutely no effect on the problem, so I'm convinced that in-tank pumps
> > would not have done much, if any, better.
> >
> > I guess nighttime travel is the only solution. :-(
> >
> > Ken H.
> >
> > From JimK's parking lot in Newark, CA
> >
> > On May 31, 2013 5:56 AM, "Kerry Pinkerton" wrote:
> >
> >>
> >>
> >> I've been following Ken Henderson and Dennis' blog of their trip out
> west
> >> and was sad to read that Ken had some vapor lock problems a couple times
> >> and some serious problems coming up out of Death Valley.
> >>
> > ...
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
|
|
|
|
| Re: Help me understand vapor lock [message #209515 is a reply to message #209388] |
Sat, 01 June 2013 09:36 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
|
Senior Member |
|
|
Didn't someone post a simple way to test the amount of crapanol in gas a few months back?
The thought of filling up with fuel that won't work in the coach when I'm 200 miles past the end of the world scares the crap out of me.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
|
|
|
|
Goto Forum:
Current Time: Sun Oct 06 04:23:15 CDT 2024
Total time taken to generate the page: 0.01485 seconds
|
GMCforum
Search
Help
Register
Login
Home
