Home » Public Forums » GMCnet » Carter 4070 electric fuel pump plumbing
| Re: [GMCnet] Carter 4070 electric fuel pump plumbing [message #261476 is a reply to message #261475] |
Wed, 10 September 2014 07:37   |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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On Wednesday, September 10, 2014, Kerry Pinkerton
wrote:
> 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.
>
>
One problem with the mechanical pumps is
THEY SUCK
which aggravates the problem with the new fuels
Better to push.
Wonder why all modern systems are ALL electric pumps ???
Erf
>
> 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, near Huntsville,
>
> 77 Eleganza II, "The Lady", 403CI, Manny Brakes, 1 ton, tranny also a 76
> Eleganza to be re-bodied as an Art Deco car hauler
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--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
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Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] Carter 4070 electric fuel pump plumbing [message #261521 is a reply to message #261476] |
Wed, 10 September 2014 17:20 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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""One problem with the mechanical pumps is
THEY SUCK
which aggravates the problem with the new fuels
Better to push.
Wonder why all modern systems are ALL electric pumps ???
Erf
I wonder how people feel when they have to spend $500 + to have the tank dropped and get a new pump every 5 to 8 years.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: Carter 4070 electric fuel pump plumbing [message #261533 is a reply to message #261306] |
Wed, 10 September 2014 19:40 |
bobby5832708
Messages: 237
Registered: November 2006
Location: Winter Springs FL
Karma: 3
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Senior Member |
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In my experience, the easier it is to replace the electric fuel pump the more unlikely it is to ever need replacement. Cars we have or have had in our family:
1. 2005 Crown Vic. 120K miles. Still has original pump. Tank does not have to be dropped, just jack the back of the car up so the rear axle is fully extended and there is enough room to do the replacement. Same way on every Ford Panther-platform vehicle (Grand Marquis, Town Car, Crown Vic).
2. 2004 Toyota Avalon. 180K miles. Still has the original fuel pump and fuel filter. Tank does not have to be dropped, access panel is under the back seat. Very easy to get to, that's why it will probably never fail. It's also a Toyota, the most troublefree car we've ever owned. Freakin car never breaks.
3. 1992 Lincoln Town Car. 240K miles when we sold it. Replaced the pump at about 150K miles because I had heard horror stories from friends and their fuel pump troubles. I didn't think that said friends had Suburbans, Tahoes, and Camaros and I had a Ford. The 90's GM's were melting the wire that powered the fuel pump, the replacement GM pumps had new-style connectors so the wire-burning would not happen again (in theory). I still wonder how long that original Ford pump would have lasted. Access was pretty easy, with the rear axle at full droop there was enough room to do the replacement without dropping the tank.
4. 199? Honda Accord. Daughter's first car. At about 150K the car wouldn't start sometimes, then after a few attempts it would start and run perfectly. I guessed that the fuel pump was going bad and replaced it. I was wrong. It was the ecu power relay that was going bad (found this out when the car wouldn't start a week later). The fuel pump access panel was under the back seat, took maybe a half hour to unnecessarily replace the pump.
5. 2001 Chevy Silverado. Now has about 150K on it and my son is on his third fuel pump. The tank cannot be dropped unless the truck's on a lift because it's a tall (rather than wide) tank. Shop wanted something like $800. The first replacement a few years ago, he and a few buddies found that the easiest way to get access to the pump was to remove the bed. Makes for a long Saturday project. Now he has a topper and a ladder rack on the truck so for the last pump replacement a few months ago he sawzalled his own access panel in the bed (since he knew exactly where the pump was located), did the replacement, and made a patch panel that he screwed in place. The next time he needs to replace the fuel pump in the Chevy he now has easy access. That's why it will probably never fail.
6. My 1974 GMC motorhome. When I bought it in 2006 the previous owner used the Carter electric pump as a selling feature because he said the GMC always started immediately and drove fine. Looking at the stack of receipts I found that this pump was installed in 1986, the mechanical pump was disconnected and looped with a piece of rubber fuel hose, electric only fuel supply. Even though it worked fine I replaced the 20 year old Carter with a new Carter just because it was 20 years old and we all know how unreliable old electric fuel pumps are! A couple of years later I added a second Carter and a couple of check valves so I now have one pump per tank. Never had a failure yet.
Also, I've never seen a mechanical fuel pump put out the 50-or-so PSI that injection requires. I wonder how long a mechanical fuel pump would last if it had to pump at that pressure. I just can't see a rubber diaphragm lasting very long at 50 PSI. I'm sure it could be done somehow, but at what cost? What did the GM fuelies of the late 50's-early 60's use for a fuel pump? I know they weren't really reliable and many Rochester injections were swapped out for a carb, was it the injection that was unreliable or did they possibly have fuel supply issues?
Executive Summary: Not all electric fuel pumps are unreliable and not all vehicles require major disassembly to get to the fuel pump.
Bob Heller
2017 Winnebago 29VE
Winter Springs FL
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| Re: [GMCnet] Carter 4070 electric fuel pump plumbing [message #261542 is a reply to message #261476] |
Wed, 10 September 2014 21:53 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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Senior Member |
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Mr ERFisher wrote on Wed, 10 September 2014 05:37
Wonder why all modern systems are ALL electric pumps ???
Erf
I suspect it is because of the higher pressures involved with electronic fuel injection. It's probably much easier to achieve those pressures with an electric pump than to design and build a high pressure mechanical pump. Think about how expensive it is to replace a fuel injection pump on a diesel for instance.
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: Carter 4070 electric fuel pump plumbing [message #261543 is a reply to message #261533] |
Wed, 10 September 2014 22:12 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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""In my experience, the easier it is to replace the electric fuel pump the more unlikely it is to ever need replacement. Cars we have or have had in our family:""
Looks like you have had lots of pump replacements in your family:)Certainly fuel injection has its own requirements. What I am trying to say is that if you have a carburetor, the most reliable pump is the original mechanical pump by far. The electric pump system usually includes the pump itself, the relay, the oil pressure switch, the dash switch or control, and a fuse somewere. When you calculate the reliability of each component and connection, the electric system has no reasonable chance of competing with a mechanical system. Its one reason the presidential limo has a carburetor and a mechanical pump
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: Carter 4070 electric fuel pump plumbing [message #261548 is a reply to message #261543] |
Thu, 11 September 2014 00:33 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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I got think about what you said on mechanical pump reliability. In my life I have only replaced or help replace 2 defective mechanical pumps. Both were on vehicles that were not mine. (A 1954 Ford and helping a GMCer at BS.) I also did replace the mechanical pump on my motorhome because it was free at the time to me. I was replacing just about every thing else on the engine after an engine fire.
Looking at electric pumps, I have had a reliability poor record. I have replaced 8 on vehicles that I own, 4 on other peoples vehicles. My daughter has an additional 3 she replaced and has it down to a 2.5 hour job including dropping and reinstalling the tank on her Blazer. I just remembered two more electric boost pumps that went out on the GMC. I carry a spare electric pump in my Blazer, Laurie's Jimmy, and my Colorado. Those are the only spares I carry other int hose vehicles than a serpentine belt and a few fuses. These numbers also do not include the fuel regulators (usually located inside the intake plenum) that at I have replaced that are part of the electric fuel pump system.
Let's see, that is 3 mechanical pumps in 30 years vs. 16 electric pumps in 24 years that I have been associated with replacing. Also throw in a 3 more regulators on the electric pump side.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Carter 4070 electric fuel pump plumbing [message #261552 is a reply to message #261548] |
Thu, 11 September 2014 00:45 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Senior Member |
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Were any of them carter 4070's ? My wife's 32 ford had a 4070 in it for more then 30 years and it was an every day driver. The electric pumps that I had problems with were diafram pumps rather then gear drive except for a holly pump.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: Carter 4070 electric fuel pump plumbing [message #261558 is a reply to message #261552] |
Thu, 11 September 2014 03:00 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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roy1 wrote on Thu, 11 September 2014 00:45Were any of them carter 4070's ? My wife's 32 ford had a 4070 in it for more then 30 years and it was an every day driver. The electric pumps that I had problems with were diafram pumps rather then gear drive except for a holly pump.
The mechanical pumps were all diaphragm. One Carter 4070 on the motor home the other was One of those things Jim B. is selling. I do not think it was a diaphragm type pump. These were no big deal since I had a mechanical pump to back them up. That was the first one, and it was installed on my motorhome by a PO. Every other electric pump was an in tank OEM pump mostly Ford and GM. Those are the ones that I carry a spare for in each car. I understand these fail most often when you let the tank get too low on fuel. They use the tank fuel for cooling. They are rotary and lock up. I have been successful temporarily by wacking the bottom of the tank to get them started again. Once you get them started do not turnoff the car until you get to the place where you are going to change them. Sometime you can successfully wack them again and sometimes not.
I just remembered a few more. They were all electrical interrupter types used on aircraft just like the Onan ones. I have never replaced a mechanical one on an airplane. Usually the airplane electric interrupter type we take them apart, and just clean them thoroughly. Then they are usually good to go again. Again they are backed up by a mechanical pump so when they fail it is no big deal. The mechanical type is actually the main pump and the electric is the back one.
The pre-startup check list has you turn on the electric pump and read the fuel pressure. Then turn it off, start the engine, and read the fuel pressure from the mechanical one. On on initial taxi and run-up prior to take off, you do it on mechanical only. Just prior to take off you turn on the electric one again and take off on both. Once you are at a safe altitude (usually cruise altitude), you turn off the electric and leave the electric off until starting to land. You do not want an engine failure on either take off or landing.
I have had three minor ones. One carb icing at about 3000, One dry tank on landing, and one vapor lock at 4000 feet. You get very busy, very quickly trying to figure out and recover from the failure.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
[Updated on: Thu, 11 September 2014 04:17] Report message to a moderator |
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| Re: Carter 4070 electric fuel pump plumbing [message #261609 is a reply to message #261606] |
Thu, 11 September 2014 12:07 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Actually the one that got my attention the most was when I ran a tank dry on final at about 300 feet after dark. There were trees all around the strip so going straight ahead and landing short was not an option. I headed for a corn field and went through (in my head) very quickly my engine failure check list. Mixture full rich, electric fuel pump on, switch tanks, verify magneto on both, and line up with the corn rows for landing. At about 50 feet the engine restarted and I went back to the unlighted airstrip for a normal landing.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Carter 4070 electric fuel pump plumbing [message #261612 is a reply to message #261609] |
Thu, 11 September 2014 12:31 |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
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Ken Burton wrote on Thu, 11 September 2014 12:07Actually the one that got my attention the most was when I ran a tank dry on final at about 300 feet after dark. There were trees all around the strip so going straight ahead and landing short was not an option. I headed for a corn field and went through (in my head) very quickly my engine failure check list. Mixture full rich, electric fuel pump on, switch tanks, verify magneto on both, and line up with the corn rows for landing. At about 50 feet the engine restarted and I went back to the unlighted airstrip for a normal landing. There was a part of a Bill Cosby routine where he talks about mom telling you to put on clean underwear in case you get in an accident. He said it doesn't matter. When you see the disaster developing, first you say it, then you do it. And that's it for the clean underwear.
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