Home » Public Forums » GMCnet » Carter 4070 electric fuel pump plumbing
| Carter 4070 electric fuel pump plumbing [message #261306] |
Mon, 08 September 2014 15:58  |
Wayne
Messages: 106
Registered: August 2004
Karma: 0
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Senior Member |
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Hi everyone,
I am installing a 4070 Carter on the outside of the LH frame. The easy plumbing ( for me)would be to cut into the line in between the selector valve and mechanical fuel pump.The mechanical pump should pull gas tru the 4070 when the selector valve is off (rear tank). I intend to control it to work with the front gas tank only using current from the selector valve. I thought ( because the instructions say it is a pull tru pump the mechanical pump can pull the gas tru the electric pump even when the electric pump is off ( which will be most of the time in my case).
Then I was reading on Genes site , I think, that another GMCer did it this way and his fuel pressure went down to 3 lbs unless the 4070 was
on ( my 4070 WON'T BE ON most of the time). I can't see why there should be a pressure drop.
WHAT SAY YOU GUYS?
HERE IS WHAT I READ.
"I run the Carter 4070 on our GMC. I also have a fuel pressure gauge mounted on the outside of the windshield. When I first installed the electric pump I put it after the selector valve so I could opperate it with either tank. What I found was I had between 5 to 6 pounds of fuel pressure using the electic and mechanical pumps. When I shut off the electric pump the fuel pressure would drop down to 3 pounds. With the electric pump bypassed I was back up to 5 pounds.
I remounted the electric pump before the selector valve and connected it to the reserve tank only. That way if I need the electric pump I just switch to the reserve tank. This way there is no drop in fuel pressure while running on the main tank which is what I do."
Wayne Lawrence
76 Birchaven
Bellflower CA
w.lawrence@verizon.net
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| Re: Carter 4070 electric fuel pump plumbing [message #261307 is a reply to message #261306] |
Mon, 08 September 2014 16:06  |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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I am not sure if my answer is helpful or not.
just how I have mine setup. not sure why you want to run the electric pump off the main tank, but you might have your reasons.
I have my electric fuel pump, between my aux, tank, and the selector valve inlet. and I have Positive wire from selector valve to fuel pump.
so my engine runs off mechanical pump, pulling from Main tank 99% of the time.
when i switch the dash switch to "aux" it switches selector to pull from "aux" tank, and also powers on the electric pump, and pushes the fuel up.
I switch my tank to "aux" just before starting the engine, I can hear it run a little bit. My engine always fires up almost instantly doing it this way. and then I switch back to "main" after I start motor. (not everytime, just when it has been parked for more then a few hours).
I also have felt what i would determine to be vapor lock on only 2 occations. and a switch of the fuel switch to Aux, fixed the hesitation-power loss/vapor lock.
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: Carter 4070 electric fuel pump plumbing [message #261309 is a reply to message #261306] |
Mon, 08 September 2014 16:16 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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I had mine in line like you are proposing and had all kinds of problems. The mechanical pump will NOT pump through the Carter 4070 reliably. It took me forever to figure out what the problem was. You have 3 choices
1. Run it all the time
2. Put it in line BEFORE the selector valve
3. Jim K sells a bypass kit to allow fuel to go around the Carter P4070 when it is not running.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Carter 4070 electric fuel pump plumbing [message #261311 is a reply to message #261306] |
Mon, 08 September 2014 16:28 |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
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Senior Member |
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Wayne,
Just put an electric fuel pump (P4070) system on a friends coach. You CANNOT pull fuel thru the 4070 as it is a gear pump. You will need to use a check valve and have a bypass around the pump. As an example see next link.
http://www.appliedgmc.com/prod.itml/icOid/562
The picture shows how to plumb it up. Jim K will sell you just the fittings or you can get them from McMasterCarr.
You also need to a low pressure shutdown switch in the electrical side to shut down the pump if the oil pressure goes away.
Go to:
and download the PDF instruction files.
You will also need:
To use in the pump control.
If your interested I have several control package schematics for the electric fuel pump. I will only send these offline for liabilities issues. If your interested contact offline.
JR Wright
78 Buskirk Stretch
75 Avion
Michigan
On Sep 8, 2014, at 4:59 PM, Wayne Lawrence wrote:
> Hi everyone,
> I am installing a 4070 Carter on the outside of the LH frame. The easy plumbing ( for me)would be to cut into the line in between the selector valve
> and mechanical fuel pump.The mechanical pump should pull gas tru the 4070 when the selector valve is off (rear tank). I intend to control it to work
> with the front gas tank only using current from the selector valve. I thought ( because the instructions say it is a pull tru pump the mechanical
> pump can pull the gas tru the electric pump even when the electric pump is off ( which will be most of the time in my case).
> Then I was reading on Genes site , I think, that another GMCer did it this way and his fuel pressure went down to 3 lbs unless the 4070 was
> on ( my 4070 WON'T BE ON most of the time). I can't see why there should be a pressure drop.
>
> WHAT SAY YOU GUYS?
>
> HERE IS WHAT I READ.
>
> "I run the Carter 4070 on our GMC. I also have a fuel pressure gauge mounted on the outside of the windshield. When I first installed the electric
> pump I put it after the selector valve so I could opperate it with either tank. What I found was I had between 5 to 6 pounds of fuel pressure using
> the electic and mechanical pumps. When I shut off the electric pump the fuel pressure would drop down to 3 pounds. With the electric pump bypassed I
> was back up to 5 pounds.
> I remounted the electric pump before the selector valve and connected it to the reserve tank only. That way if I need the electric pump I just
> switch to the reserve tank. This way there is no drop in fuel pressure while running on the main tank which is what I do."
> --
> Wayne Lawrence
> 76 Birchaven
> Bellflower CA
> w.lawrence@verizon.net
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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| Re: Carter 4070 electric fuel pump plumbing [message #261362 is a reply to message #261306] |
Tue, 09 September 2014 06:29 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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The pump I bought (Mr Gasket) is designed for a carburetor, says ~~4psi on it. Seems to work fine, it was less than $50 at O'Rielly's. I put it in the aux tank line before the selector valve.
--johnny
'76 23' transmode norris
Braselton Ga.
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
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| Re: [GMCnet] Carter 4070 electric fuel pump plumbing [message #261386 is a reply to message #261381] |
Tue, 09 September 2014 09:06 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Armand,
All I did was quote what Doc Frohmader noted which aligns with what Dick says. I have NO experience with the Carter 4070.
I currently have a small Facet pump (4 psi) that comes on and feeds the mechanical fuel pump when I have a vapor lock problem. I was
installed by JimB YEARS ago and works just fine. Yes, I realize that if the diaphragm fails it will pump the crankcase full of gas.
Yes, I am aware of some guy that failed several engines because he moved a fuel pump with a defective diaphragm from engine to
engine.
I purchased and will be installing in tank pumps from a Buick Riviera which put out 5-7 psi. However, I am going to feed a surge
tank which will have a return plumbed to the fuel filler vent so the net delivery pressure to the mechanical fuel pump will be damn
near zero. That system was not my idea it was Steve Southwood's. It allows you to convert to EFI simply by plumbing the outlet of
the surge tank to the EFI pump. Yes I am aware that it adds an extra pump, However, I'd rather have fuel lines under the coach
pressurized to 7 psi rather than the higher pressure an EFI system requires because if a leak were to occur the higher pressure
would result in more fuel being pumped overboard.
Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Armand Minnie
Sent: Tuesday, September 09, 2014 8:49 AM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] Carter 4070 electric fuel pump plumbing
Rob, I don't understand your answer. The P4070 is supposed to put out 5-7 pounds which Dick Paterson said was correct. Are you
saying you don't trust it to be used full time?
--
Armand Minnie
Marana, AZ
'76 Eleganza II TZE166V103202
http://www.minniebiz.com
http://www.gmcws.org
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: Carter 4070 electric fuel pump plumbing [message #261390 is a reply to message #261306] |
Tue, 09 September 2014 10:31 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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Everybody has their own opinion...
but here is mine based on my experience:
good OEM mechanical pumps are extremely reliable. for our GMC, and other vehicles i have dealt with, are also fairly inexpensive.
Yes they have a potential, to rupture, and fill your crankcase with fuel. but my opinion, even though it happens, I think the statistics would show it to be a very rare occurrence.
my personal experience, is dealing with lots of electric fuel pump failures. However with the poor gas these days, installation of some sort of electric pumps is almost getting to be mandatory to fix vapor lock.
I also have had good luck with a carter 4070 I installed in my jeep wagoneer. and it feels to be quite a bit better built pump then a faucet, airtex, or mr. gasket. Even though i have both a faucet(aux line), and mr. gasket(onan) that has not failed yet on my wagoneer, i have 1 each of those brands that went bad on my vw buggy, and am now back to a mechanical pump on my Volkswagens.
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: [GMCnet] Carter 4070 electric fuel pump plumbing [message #261395 is a reply to message #261390] |
Tue, 09 September 2014 11:23 |
dan molnes
Messages: 166
Registered: October 2011
Karma: 1
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Senior Member |
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jon, I think I'll install the 4070 like you have it in yours it seems to be
the best option,
you wired pos. from the selector valve to the pump and pump grounds its
self to frame ?
also I would like to see some pics of the wagoneer after you had it all
fixed up
did the painter finally show up ? have a good time at the ralley dan
On Tue, Sep 9, 2014 at 8:31 AM, Jon Roche wrote:
> Everybody has their own opinion...
>
> but here is mine based on my experience:
>
> good OEM mechanical pumps are extremely reliable. for our GMC, and other
> vehicles i have dealt with, are also fairly inexpensive.
>
> Yes they have a potential, to rupture, and fill your crankcase with fuel.
> but my opinion, even though it happens, I think the statistics would show
> it to be a very rare occurrence.
>
> my personal experience, is dealing with lots of electric fuel pump
> failures. However with the poor gas these days, installation of some sort
> of
> electric pumps is almost getting to be mandatory to fix vapor lock.
>
> I also have had good luck with a carter 4070 I installed in my jeep
> wagoneer. and it feels to be quite a bit better built pump then a faucet,
> airtex,
> or mr. gasket. Even though i have both a faucet(aux line), and mr.
> gasket(onan) that has not failed yet on my wagoneer, i have 1 each of those
> brands that went bad on my vw buggy, and am now back to a mechanical pump
> on my Volkswagens.
>
> --
> 75 palm beach
> St. Cloud, MN
> http://lqqkatjon.blogspot.com/
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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| Re: Carter 4070 electric fuel pump plumbing [message #261397 is a reply to message #261306] |
Tue, 09 September 2014 11:59 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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Dan-
Wagoneer paint job is still a mess.... I will send you a picture where it is at. It was to get color today, but I have heard that for months. Been doing what i can without getting myself arrested to help the process along.
you are correct, positive jumpered over from the selector wire, to the pump. and ground to frame. I have an inline filter prior to the pump.
I am using just a little cube pump on the GMC, My personal opinion, even though I think the 4070 is a better pump, the 4070 is bigger and odder to mount. so pay attention to mounting, I know on my wagoneer the 4070 hangs down below the frame rail a little bit, and that is where the wires are at. I think a cube pump in this application(used occasionally, and as a backup) would be a easier install.
I will try to take a picture of how i have that cube pump mounted up. and if I ever get my wagoneer back, I can send you a picture of that mounting bracket.
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: [GMCnet] Carter 4070 electric fuel pump plumbing [message #261419 is a reply to message #261397] |
Tue, 09 September 2014 17:30 |
dan molnes
Messages: 166
Registered: October 2011
Karma: 1
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Senior Member |
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Sorry to hear about the wagoner .some people ought to be taken out to get reprioritized new word but you know what I mean ,thanks for the info
Sent from my iPhone
> On Sep 9, 2014, at 9:59 AM, Jon Roche wrote:
>
> Dan-
> Wagoneer paint job is still a mess.... I will send you a picture where it is at. It was to get color today, but I have heard that for months. Been
> doing what i can without getting myself arrested to help the process along.
>
>
> you are correct, positive jumpered over from the selector wire, to the pump. and ground to frame. I have an inline filter prior to the pump.
>
> I am using just a little cube pump on the GMC, My personal opinion, even though I think the 4070 is a better pump, the 4070 is bigger and odder to
> mount. so pay attention to mounting, I know on my wagoneer the 4070 hangs down below the frame rail a little bit, and that is where the wires are
> at. I think a cube pump in this application(used occasionally, and as a backup) would be a easier install.
>
> I will try to take a picture of how i have that cube pump mounted up. and if I ever get my wagoneer back, I can send you a picture of that mounting
> bracket.
>
>
>
> --
> 75 palm beach
> St. Cloud, MN
> http://lqqkatjon.blogspot.com/
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: Carter 4070 electric fuel pump plumbing [message #261434 is a reply to message #261306] |
Tue, 09 September 2014 19:36 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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The Mr Gasket pumps come with a filter which screws on the inlet. They have an integral check valve if you want to just run two of them with combined output. I was gonna do two (had a spare off the old Jetta toad) but the tech at Mr Gasket nixed the idea. He says alcohol wil destroy the seals in the 12D (Diesel) one; and the diesel will destroy the seals in the 12 (gasoline ) one. Anyone who has a VW 1600 or 1900 non-TDI diesel with th front seal of the pump leaking the prime down can have the 12D for shipping. I resurrected a leak - down pump for three years before the seal got to where it leaked fuel. At that point, it wants to go to Diesel Care and Performance in TN for rebuild.
--johnny
76 23' transmode norris
Braselton GA
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
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| Re: Carter 4070 electric fuel pump plumbing [message #261460 is a reply to message #261340] |
Tue, 09 September 2014 22:57 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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armandminnie wrote on Mon, 08 September 2014 20:24I always wonder why people don't just use the electric pump and remove the mechanical pump. Why not just use it all the time? If an electric pump fails it won't hurt the engine. If a mechanical pump fails (the right way) it can destroy the engine. Just wondering.
My experience has been that the mechanical pump is dramatically more reliable than an electrical pump system (including pump, wiring, relay, oil pressure switch)
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: Carter 4070 electric fuel pump plumbing [message #261471 is a reply to message #261463] |
Wed, 10 September 2014 05:11 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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As I was leaving Bean Station on a Sunday afternoon a few years ago, I came up one of our GMCers whose coach died climbing the hill up over the mountain on 25E. His mechanical fuel pump quit. I hooked onto him with my Blazer and towed him the rest of the way up the hill (4 lane divided highway) and then turned round and towed him back to BS. We were able to find a the correct replacement pump in stock at a NAPA auto parts store and in a couple of hours total time he was on his way again. I guess they fail once every 30 years or so.
Try that with a Mr. Gasket or even a Carter P4070 on a Sunday afternoon.
If total electric is your thing, then I like Ken H's installation. He has 2 P4070's (one for each tank). If his electric pump fails then he can switch tanks and pumps to keep going.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Carter 4070 electric fuel pump plumbing [message #261475 is a reply to message #261471] |
Wed, 10 September 2014 06:53 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Senior Member |
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Ken Burton wrote on Wed, 10 September 2014 05:11...If total electric is your thing, then I like Ken H's installation. He has 2 P4070's (one for each tank). If his electric pump fails then he can switch tanks and pumps to keep going.
Because of vapor lock, this is what I did. The wife freaks if the coach stumbles like it did in Branson.
I used the Airtex pump (in stock at the local Advance) and installed them outside the frame with check valves. I did NOT drop the tanks because the PO had had them dropped and new rubber ethanol rated gas line installed. I did keep the rubber lines as short as possible. In addition to the low oil cutoff and the relays to power the pumps, I wanted an EMERGENCY fuel pump overide/prime switch. I can envision situations where I'm willing to risk my engine a few more seconds with no oil pressure to get out of the middle of an intersection, off a railroad track, or similar. Starting is instantaneous.
The old tank selector is not used but the switch now controls the relays to determine which pump runs. Check valves after the pumps to prevent back pressure and gas filters in front of them, and another up by the engine, and the one in the Paterson carb. Probably over filtered.
Somehow I never took any photos of the installation ... I do have this shot of the cover I made to protect the pumps and lines from road trash. 1/8" aluminum bolted through the frame and through the aluminum rocker extrusion. The two holes allow access to the pump wiring and was cut with a 2 1/2" hole saw. The ends are open for ventilation
http://www.gmcmhphotos.com/photos/misc/p55854-fuel-pump-cover.html
Because I'm chicken and new to this setup. I did not remove the newer mechanical pump and put on a block off plate. Instead, I just made a loop from rubber gas line and hooked the input to the output. If something goes nuts with my electric pumps on the way to Wisconsin, I can switch back to the mechanical pretty easy.
Not saying it's right or the best it's just what I did.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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