fuel pump problem again and again
Thread Starter
3rd Gear
Joined: Aug 2017
Posts: 3
Likes: 0
fuel pump problem again and again
replaced fuel pump four times. the last time I replaced fuel regulator and pig tail also pump and wiring. fourth start up fuel pump out again. cleaned tank out replaced in line fuel filter and sock on pump as well. Can not case down repeated fail of fuel pump. Any help out there,
Team Owner
Joined: Dec 1999
Posts: 34,873
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Are you sure that it is the pump itself that is failing? Could be a bad F/P relay that is not always powering up the pump. If you have one of the failed pumps, try to run it on a bench; apply 12v and see if it runs.
What brand of fuel pump are you buying? I would go with a GM OEM version or AC Delco Professional Grade. No way would I even consider stuff like Dorman or Standard Products or any of the so-called "white box" parts like those sold thru the chain parts stores.
What brand of fuel pump are you buying? I would go with a GM OEM version or AC Delco Professional Grade. No way would I even consider stuff like Dorman or Standard Products or any of the so-called "white box" parts like those sold thru the chain parts stores.
Safety Car
Joined: Aug 2013
Posts: 4,427
Likes: 604
From: Minneapolis Mn
4 pumps going bad in the same vehicle doesn't seem right. There has to be something else going on here. Whether it's the installation procedure, some other part affecting it or what - no idea.
About the only comment I can made is the same thing referenced whether in a Vette or some other brand/model of vehicle. Are you consistently running the tank dry or low on fuel? the gas acts as a coolant for the pump and it can overheat if consistently/exposed to air. Just a thought.
Team Owner
Joined: Jul 2004
Posts: 28,430
Likes: 3,284
From: Hartford WI
That part is total BS. If it was making that much heat, you'd vaporize your fuel all day long. Also Tom400CFI has proven an old used pump can run for 45 minutes without coolant. If it were to generate heat, and it does, it is going to be slight, You wouldn't want a hot rock in the tank, would you? That is the grandma of old wives tail
Safety Car
Joined: Aug 2013
Posts: 4,427
Likes: 604
From: Minneapolis Mn
That part is total BS. If it was making that much heat, you'd vaporize your fuel all day long. Also Tom400CFI has proven an old used pump can run for 45 minutes without coolant. If it were to generate heat, and it does, it is going to be slight, You wouldn't want a hot rock in the tank, would you? That is the grandma of old wives tail
To me it's no different than if you run an engine with low coolant or airlocked. It's designed to have heat removed through the mechanisms designed to do it, take away that coolant methodology and eventually something is going to give up the ghost.
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Team Owner
Joined: Jul 2004
Posts: 28,430
Likes: 3,284
From: Hartford WI
Believe it or not, your choice. If it was poppycock, why would the manufacturers say to not do it? I know at least 3 people including my kid that consistently ran the tank very low and had premature fuel pump failures. It didn't happen immediately but it did happen prior to expected life expendency.
To me it's no different than if you run an engine with low coolant or airlocked. It's designed to have heat removed through the mechanisms designed to do it, take away that coolant methodology and eventually something is going to give up the ghost.
To me it's no different than if you run an engine with low coolant or airlocked. It's designed to have heat removed through the mechanisms designed to do it, take away that coolant methodology and eventually something is going to give up the ghost.
Your theory will have the pump become a mini immersion heater in the tank. How much fuel would you lose? If you are talking cooling, it is done by the fuel in the tank or you will evaporate the fuel. Going through the pump, sure. As long as fuel flows there will be cooling. When it stops your pump stops
Drifting
Joined: Jan 2005
Posts: 1,354
Likes: 324
From: San Antonio Tx
I had an intermittent FP failure even after replacing all of the wiring. The problem turned out to be the bulkhead connector where the wiring goes into the tank. Original fuel pump wiring does not like ethanol. I replaced my filler neck/fuel sender with a stainless steel unit.
Le Mans Master
Joined: Feb 2005
Posts: 6,479
Likes: 565
From: Clearwater Florida
replaced fuel pump four times. the last time I replaced fuel regulator and pig tail also pump and wiring. fourth start up fuel pump out again. cleaned tank out replaced in line fuel filter and sock on pump as well. Can not case down repeated fail of fuel pump. Any help out there,
Intermediate
Joined: Sep 2016
Posts: 46
Likes: 3
From: Carlisle PA
Fuel pump out
IN my 1998 Chevy Tahoe a few years ago, The fuel gauge sending unit went bad. I ran it out of gas twice in about a months time.
2 weeks later... fuel pump went out.
Might be folklore... But if anyone at my house gets caught with less then 1/4 tank of gas...
2 weeks later... fuel pump went out.
Might be folklore... But if anyone at my house gets caught with less then 1/4 tank of gas...
Team Owner
Joined: Jul 2004
Posts: 28,430
Likes: 3,284
From: Hartford WI
I have run out of gas way more than that. I have only replaced the pump because I wanted a better one. So I'm betting it is folklore or you should buy stocks in fuel pumps since I am always running past empty mark and sometimes get caught.
Melting Slicks
Joined: Jan 2008
Posts: 2,054
Likes: 120
From: AZ
In many aircraft, the fluids that run through variuous pumps do the above and there are certification standards that require minimum fluid levels in such tanks, to keep all within temperture limits. Some newer Boeings, particularly long range types, employ fuel tank heat exhangers to cool the hydraulic fluid used to operate flight controls while keeping the fuel above minimum temperatures during extended high altitude, very zub-freezing, conditions.
With the well-known low fuel indication problems with C4s, drivers are wise to start looking at refills around 1/2 tank, unless a fix was accomplished and the low fuel levels are accurate; then perhaps 1/4 tank.
Last edited by whalepirot; Aug 16, 2017 at 11:41 AM.
Team Owner
Joined: Jul 2004
Posts: 28,430
Likes: 3,284
From: Hartford WI
Gasoline is a lubricant for the pump and may serve as a heat transfer agent as well; i.e. coolant.
In many aircraft, the fluids that run through variuous pumps do the above and there are certification standards that require minimum fluid levels in such tanks, to keep all within temperture limits. Some newer Boeings, particularly long range types, employ fuel tank heat exhangers to cool the hydraulic fluid used to operate flight controls while keeping the fuel above minimum temperatures during extended high altitude, very zub-freezing, conditions.
With the well-known low fuel indication problems with C4s, drivers are wise to start looking at refills around 1/2 tank, unless a fix was accomplished and the low fuel levels are accurate; then perhaps 1/4 tank.
In many aircraft, the fluids that run through variuous pumps do the above and there are certification standards that require minimum fluid levels in such tanks, to keep all within temperture limits. Some newer Boeings, particularly long range types, employ fuel tank heat exhangers to cool the hydraulic fluid used to operate flight controls while keeping the fuel above minimum temperatures during extended high altitude, very zub-freezing, conditions.
With the well-known low fuel indication problems with C4s, drivers are wise to start looking at refills around 1/2 tank, unless a fix was accomplished and the low fuel levels are accurate; then perhaps 1/4 tank.
https://www.corvetteforum.com/forums...post1590728908
According to his comments, it never got to over 100
Melting Slicks
Joined: Jul 2005
Posts: 2,649
Likes: 863
Yikes - 4 Fuel Pump failures.... something is clearly not right !!!
First off I would check fuel lines for restriction. I'd probably start by blowing them out with compressed air and having someone check to verify that lots of air is flowing through the lines (remember to check the return line as well).
Wherever you are getting your fuel pumps from - I'd go with a different brand for Number 5. Both Racetronix and Walbro make High Performance fuel pumps that fit the C4 - maybe give one of them a try.... I would also check current draw of pump number 5 after you install it (you should be able to get current draw from oil pressure switch connector).
First off I would check fuel lines for restriction. I'd probably start by blowing them out with compressed air and having someone check to verify that lots of air is flowing through the lines (remember to check the return line as well).
Wherever you are getting your fuel pumps from - I'd go with a different brand for Number 5. Both Racetronix and Walbro make High Performance fuel pumps that fit the C4 - maybe give one of them a try.... I would also check current draw of pump number 5 after you install it (you should be able to get current draw from oil pressure switch connector).
Intermediate
Joined: Sep 2016
Posts: 46
Likes: 3
From: Carlisle PA
From oil pressure switch?
I would think you would need to get draw readings from the relay base terminals?
Bridge the terminals with relay removed, thus bypassing the relay and putting an amp meter in the jumper?
I have lots to learn.
Melting Slicks
Joined: Jul 2005
Posts: 2,649
Likes: 863
Not sure of OP's vehicle year - but I know on the LT1/LT4 cars the power to run the Electric Fuel Pump is routed through the oil pressure switch. Yes there is a fuel pump relay - and it's sole job is to run the pump when the key is first turned on, or when the engine is cranking - the rest of the time the power to run the pump comes from the oil pressure switch... If the engine dies - the oil pressure drops to zero and the fuel pump is shut off.
Now - as far as getting to the relay - again on the LT1/LT4 cars it's tucked up under the pass side dashboard face. For the most part - you're working by feel... Not a whole bunch of fun!!! While the oil pressure switch is also annoying to get to - IMO - it's not as bad to get to as the fuel pump relay.
Now - as far as getting to the relay - again on the LT1/LT4 cars it's tucked up under the pass side dashboard face. For the most part - you're working by feel... Not a whole bunch of fun!!! While the oil pressure switch is also annoying to get to - IMO - it's not as bad to get to as the fuel pump relay.
Team Owner
Joined: Jul 2004
Posts: 28,430
Likes: 3,284
From: Hartford WI
Not sure of OP's vehicle year - but I know on the LT1/LT4 cars the power to run the Electric Fuel Pump is routed through the oil pressure switch. Yes there is a fuel pump relay - and it's sole job is to run the pump when the key is first turned on, or when the engine is cranking - the rest of the time the power to run the pump comes from the oil pressure switch... If the engine dies - the oil pressure drops to zero and the fuel pump is shut off.
Now - as far as getting to the relay - again on the LT1/LT4 cars it's tucked up under the pass side dashboard face. For the most part - you're working by feel... Not a whole bunch of fun!!! While the oil pressure switch is also annoying to get to - IMO - it's not as bad to get to as the fuel pump relay.
Now - as far as getting to the relay - again on the LT1/LT4 cars it's tucked up under the pass side dashboard face. For the most part - you're working by feel... Not a whole bunch of fun!!! While the oil pressure switch is also annoying to get to - IMO - it's not as bad to get to as the fuel pump relay.
Race Director
Joined: Oct 2005
Posts: 11,770
Likes: 175
From: Rolla Missouri
2021 C4 of the Year - Unmodified Finalist
St. Jude Donor '10 thru '25
https://www.corvetteforum.com/forums...t-failing.html
https://www.corvetteforum.com/forums...fuel-pump.html
https://www.corvetteforum.com/forums...right-lt1.html
I am not a mechanic, and have no first hand experience.
But over the years this has been brought up many times.
Last edited by RollaMo-LT4; Aug 19, 2017 at 12:13 PM.