Home » Public Forums » GMCnet » Trip Report II (Mechanicals)
| Trip Report II [message #364974] |
Thu, 24 June 2021 23:20  |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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Senior Member |
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In my previous trip report, I stated that the coach ran great the whole trip EXCEPT for some fuel starvation issues while climbing long steep grades in extremely hot temperatures. Here is the back story and the reason I was a little surprised by this:
I have had "vapor lock" issues ever since the first drive with this coach back in 2008. I have done nearly everything conventional wisdom says should fix this problem, from installing a heat dissipator under the carburetor, Making sure all my fuel filters are fresh, adding an electric pusher pump by the gtas tanks, installing a Gary Rockwell aluminum intake manifold, without a heat crossover, mking sure my fan clutch is working, and even insulating the bottom of my gas tanks.
Finally, after rebuilding the engine and transmission about 3-1/2 years ago, I relocated my fuel hoses to the OUTSIDE of the frame, added a canister type filter, and installed a Carter 4070 electric pump, fed electricity by a relay, also outside the frame, and the problem was finally gone. For a while anyway.
The last few hot weather Summer trips, it has begun to happen again, usually after several hours of driving in the heat.
I guess I will change out all the filters again, check the integrity of the tank bottom insulation, and probably do a tune-up and see what that does.
I suspect the quality of the gas may have something to do with the problem and I admit, I am guilty of buying the cheapest gas I can get. I have had mixed results with gas from Flying-J and even Chevron in the past, so I'm not convinced that's it.
Do electric (or mechanical for that matter) fuel pumps tend to get weaker as they age? The Carter is only a little over three years old and has about 25,000 miles on it. I will replace it if the consensus is that they wear out and it might help. b ut it seems like it should not be the problem either.
It's very frustrating to know you have the power to easily climb a long grade, but you find yourself limping along the shoulder at 20 mph until you top the hill.
Any ideas or advice?
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
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| Re: Trip Report II [message #364976 is a reply to message #364974] |
Fri, 25 June 2021 07:14  |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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My experience was i started noticing my switching to aux to engage my electric fuel pump one summer did not work as effective. It used to clear any chug/hesitation instantly and there was time it kinda hesitant for longer.
One trip it seemed worse. So I did change filters. And it was back to normal.
So I would guess it is your filters.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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| Re: Trip Report II [message #365002 is a reply to message #364974] |
Fri, 25 June 2021 22:21 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Electric pumps have a horrible reliability rating. There have been reports here of bad new out of box. Factory in tank are bad enough, but aftermarket worse. I think if you run them dry ever at all they are then diminished in performance. I would test pressure coming from the pump and use that info compared to rated specs to make my decision on whether to replace .
My last trip I had zero vapor lock in 90s F temps. My crossover is restricted not blocked, I had my air cleaner preheat connected and operational. Never needed the Aux pump. I even had 30 mins of bumper to bumper stop and go. Only thing is I was only at 550’ elevation and I had just installed my new proto exact OEM copy exhaust system. Stumped as usually I would get flat spot VL in the past. Gas was a mix of cheap brand and name brand but assuming both summer blend at this point.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] Re: Trip Report II [message #365005 is a reply to message #365003] |
Fri, 25 June 2021 22:46 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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Senior Member |
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Gary,
I just happen to have that information written down:
K.T Refractories Ceramic Fiber Blanket
Temp: 2300 degrees F
Product Code MYTX1260
Density: 8#/cu-ft
I glued it to sheet metal and screwed that to the bottom of the frame.
Frankly, I'm not sure how much it helped. The gas tanks still boil on hot days.
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
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| Re: [GMCnet] Re: Trip Report II [message #365006 is a reply to message #365005] |
Fri, 25 June 2021 22:48 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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Senior Member |
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Oh, and it's about an inch thick Used for fireplaces.
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
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| [GMCnet] Re: Trip Report II [message #365007 is a reply to message #365006] |
Fri, 25 June 2021 23:17 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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If your pump is a rotary vain like the carter, they will wear fast if your
not using a filter.
There is dirt in your tank as the air displaces the fuel as it goes out and
that air is not filtered.
I think I have over 40,000 miles on my carter pump with a replacable
cartridge filter.
Yes it runs full time.
Also the Tank Selector valve should be replaced if not done in last 7-8
yers as it has a rubber grommet that is know to creat restriction.
Always replace the filter at the carb. as it is a very small capacity and
fills up even if you fave a filter ahead of it. That filter will look clean
till you cut it ope and realize the fuel flow from inside to out.
On Fri, Jun 25, 2021 at 8:48 PM Carl Stouffer wrote:
> Oh, and it's about an inch thick Used for fireplaces.
> --
> 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
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Re: Trip Report II [message #365008 is a reply to message #365007] |
Fri, 25 June 2021 23:39 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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Senior Member |
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I got all that stuff from you three years ago, Jim.
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
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| [GMCnet] Re: Trip Report II [message #365016 is a reply to message #365006] |
Sat, 26 June 2021 11:39 |
Rollerg
Messages: 111
Registered: November 2014
Location: Marysville, MI
Karma: 0
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Senior Member |
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Thanks!
Gary Coaster / Reno, NV
1977 GMC Eleganza ll
GMC RV Day Night Shade Sales
GMCShades@gmail.com
www.GMCMotorhomemarketplace.com/GMC_Shades/
> On Jun 25, 2021, at 8:48 PM, Carl Stouffer wrote:
>
> Oh, and it's about an inch thick Used for fireplaces.
> --
> 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
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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| [GMCnet] Re: Trip Report II [message #365017 is a reply to message #365005] |
Sat, 26 June 2021 11:40 |
Rollerg
Messages: 111
Registered: November 2014
Location: Marysville, MI
Karma: 0
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Senior Member |
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Thanks. Big help.
Gary Coaster / Reno, NV
1977 GMC Eleganza ll
GMC RV Day Night Shade Sales
GMCShades@gmail.com
www.GMCMotorhomemarketplace.com/GMC_Shades/
> On Jun 25, 2021, at 8:47 PM, Carl Stouffer wrote:
>
> Gary,
>
> I just happen to have that information written down:
>
> K.T Refractories Ceramic Fiber Blanket
>
> Temp: 2300 degrees F
>
> Product Code MYTX1260
>
> Density: 8#/cu-ft
>
> I glued it to sheet metal and screwed that to the bottom of the frame.
>
> Frankly, I'm not sure how much it helped. The gas tanks still boil on hot days.
> --
> 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
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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| [GMCnet] Re: Trip Report II [message #365018 is a reply to message #365005] |
Sat, 26 June 2021 11:41 |
Rollerg
Messages: 111
Registered: November 2014
Location: Marysville, MI
Karma: 0
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Senior Member |
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Also remember you are in one of the hottest parts of the country.
Gary Coaster / Reno, NV
1977 GMC Eleganza ll
GMC RV Day Night Shade Sales
GMCShades@gmail.com
www.GMCMotorhomemarketplace.com/GMC_Shades/
> On Jun 25, 2021, at 8:47 PM, Carl Stouffer wrote:
>
> Gary,
>
> I just happen to have that information written down:
>
> K.T Refractories Ceramic Fiber Blanket
>
> Temp: 2300 degrees F
>
> Product Code MYTX1260
>
> Density: 8#/cu-ft
>
> I glued it to sheet metal and screwed that to the bottom of the frame.
>
> Frankly, I'm not sure how much it helped. The gas tanks still boil on hot days.
> --
> 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
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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| [GMCnet] Re: Trip Report II [message #365028 is a reply to message #365016] |
Sat, 26 June 2021 14:49 |
Emery Stora
Messages: 959
Registered: January 2011
Karma: 4
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Senior Member |
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Sometimes insulating a fuel tank does a better job at keeping the heat in instead of keeping it out.
Emery Stora
emerystora@mac.com
> On Jun 26, 2021, at 10:39 AM, Gary wrote:
>
> Thanks!
>
> Gary Coaster / Reno, NV
> 1977 GMC Eleganza ll
> GMC RV Day Night Shade Sales
> GMCShades@gmail.com
> www.GMCMotorhomemarketplace.com/GMC_Shades/
>
>> On Jun 25, 2021, at 8:48 PM, Carl Stouffer wrote:
>>
>> Oh, and it's about an inch thick Used for fireplaces.
>> --
>> 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
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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| Re: [GMCnet] Re: Trip Report II [message #365029 is a reply to message #365028] |
Sat, 26 June 2021 15:48 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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Senior Member |
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Emery Stora wrote on Sat, 26 June 2021 12:49Sometimes insulating a fuel tank does a better job at keeping the heat in instead of keeping it out.
Emery Stora
emerystora@mac.com
Hmmm...Never thought of that.
It worked (or so they said) for a couple of other local guys, so I gave it a try. I don't think it did any harm, but It is something to check.
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
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| [GMCnet] Re: Trip Report II [message #365031 is a reply to message #365029] |
Sat, 26 June 2021 16:44 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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On the tank, use the insulation as a reflector only by putting it on the
bottom snf by the exhaust that run down the side.
We stock that heat shield.
On Sat, Jun 26, 2021 at 1:48 PM Carl Stouffer wrote:
> Emery Stora wrote on Sat, 26 June 2021 12:49
>> Sometimes insulating a fuel tank does a better job at keeping the heat
> in instead of keeping it out.
>>
>> Emery Stora
>> emerystora@mac.com
>
> Hmmm...Never thought of that.
>
> It worked (or so they said) for a couple of other local guys, so I gave it
> a try. I don't think it did any harm, but It is something to check.
> --
> 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
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Re: Trip Report II [message #365038 is a reply to message #365018] |
Sat, 26 June 2021 21:19 |
boybach
Messages: 566
Registered: December 2020
Location: Vancouver Island
Karma: 4
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Senior Member |
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Rollerg wrote on Sat, 26 June 2021 09:41Also remember you are in one of the hottest parts of the country.
Temps in BC supposed to hit 120f this weekend, 100f+ on Vancouver Island ...so pretty hot here too!
Larry
Larry - Victoria BC -
1977 ex-Palm Beach "Ol' Leaky" 40,000 miles, PO said everything working but forgot the word NOT. Atwood helium fridge, water heater & furnace. SS exhaust system, Onan, Iota Converter, R134A, New fuel lines & heat exchange hoses
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| Re: Trip Report II [message #365048 is a reply to message #364974] |
Sun, 27 June 2021 11:37 |
Gregory keller
Messages: 12
Registered: July 2019
Karma: 0
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Junior Member |
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I was having the same problem used all of the counter measures one could think of with some improvements. Only when I started using Non Ethanol gas did my problems finally go away . I know it’s more expensive but it gives me peace of mind while driving . I use the App Pure Gas which shows you every gas station that sells Non Ethanol gas stations in America you’ll find they have thousands out there . Just takes a little planning with your gas stops . You might not need Non Ethanol in the winter cooler months but during the hot summer months I don’t leave home without it . You’ll also find you will get better gas mileage using Non Ethanol gas as a bonus against the higher price.
[Updated on: Sun, 27 June 2021 13:49] Report message to a moderator |
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| Re: Trip Report II [message #365050 is a reply to message #364974] |
Sun, 27 June 2021 13:07 |
Tom Katzenberger
Messages: 399
Registered: June 2019
Location: Kingsville, MD
Karma: 4
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Do fuel injection system suffer the same issue with ethanol and vapor issues?
Tom & Oki Katzenberger,
Kingsville, Maryland,
1977 23' Birchaven, 455 C.I.D., Micro Level, Howell EBL-EFI Spark Control, Macerator, York Air Compressor, 6 Wheel Disc, Quadra Bag, Onan W/Bovee Ignition
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| Re: Trip Report II [message #365051 is a reply to message #365050] |
Sun, 27 June 2021 13:39 |
Gregory keller
Messages: 12
Registered: July 2019
Karma: 0
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Good question I can only speak from my experience with my carburetor fueled motor . I imagine with fuel injection because the fuel is under so much pressure vapor lock shouldn’t be a problem . I’m sure the fuel injection experts here could weigh in this .
[Updated on: Sun, 27 June 2021 13:41] Report message to a moderator |
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