Help! fuel pump problem

[mutley]

Hi. my name is Bruce, I have a 88 c4 5.7 automatic lovelly car i adore it but it has an issue with the fuel system. in heavy traffic after the fan cuts in a few times it seems to faulter like ts starving for fuel, low to no pressure in fuel rail even with filter off the is no fuel pumping through and the thing is if you leave it and let it cool right down it will start up.
Im not sure what it is i have a suspicion it may be fuel relay or even oil pressure switch just wandering if anyone has come across this before and if so where is the fuel relay or is there any knowen fix ... need help here its embarrasing to brake down in the city in a vette everyone looking at me ...

 

[vetteboy86]

Replacing the pump is pretty straightforward. When you determine if the pump is bad, post back and let us know.

 

[roger longman]

Hi Bruce, Good to hear from you, the guys on here will soon have you going in the right direction. I've also got an '88 and am originally from Purley, now California for the last 13 years. Your team are off to a bit of a rocky start, mine, Crystal Palace, are having a little luck, for a change......Roger.

 

[mutley]

thanks

Thank you guys for all your help i shall look into all the ideas you have come up with hopefully it will cure the problem oh and yes my team aint doin good at all.. lets hope my vette does better with all your help.. great bunch of guys here freindly and helpful.. apreciated.. please excuse the spelling.

 

[Hib Halverson]

Have you documented a loss of fuel pressure or so you just suspect that?

 

[mutley]

there is a loss of pressure but it obviously occures when the car starts to splutter and starve for fuel then stalls and wont start again till it cools otherwise while driving the car at higher rpm it most definately loses no pressure it seems to occur when im idleing and engine is hot fan cuts in a few times then it seems to die. Do you have a suspicion on the issue ?

 

[Hib Halverson]

If you've documented a pressure loss either by running the fuel pressure tests in the Service Manual or by road testing with a fuel pressure gauge attached to the windshield for viewing, then follow the diagnostic information in the Service Manual.

Loss of fuel pressure can be caused by a number of issues and some of them are unrelated to the pump. In no certain order some of them are

pump
ball check in the pump assy.
fuel pump pickup.
restricted fuel filter
restricted fuel pipes or hoses
faulty fuel pressure regulator

 

[mutley]

Thanks for bringing that to light for me. it's appreciated. would any of that in your opinion explain why it runs perfectly well at all times unless im in heavy traffic ? and when i say perfectly well i mean perfectly well at high rev , high speed or not .

 

[John Robinson]

Since we don't know much about your car yet I am going out on a limb. If it is a low mileage 88 that you found then I would lean towards the fuel pump and tank being corroded. some time ago this picture was posted from a early low mileage car.

As you can see time and moisture from storage has this fuel pump and pick up filter ready for replacement. This could be your problem. As said earlier the fuel pump removal is probable the easiest repair you can make on any car. What you need to do is get a fuel line pressure gauge and see what the pressure is when you just turn on the key. Then turn off the key and see if it holds that pressure. Then start the engine and record what that pressure is. At this point I am not familiar with the 88 set up so you will need to get an fsm and follow the test procedure for the fuel system. Post the pressure readings when you get them and let us know more about your pride and joy.

 

[boomdriver]

Thanks for bringing that to light for me. it's appreciated. would any of that in your opinion explain why it runs perfectly well at all times unless im in heavy traffic ? and when i say perfectly well i mean perfectly well at high rev , high speed or not .

I'm going to assume that you changed BOTH the fuel screen (intank) AND the filter inline....

Without a new inline filter can there ain;t gonna be any gas in the rails much less under pressure,.


As pressure builds the crap in the fliter packs against the screens and clogs the passage. As pressure bleeds off after sitting awhile the crap settles and flow can ressume. As soon as the engine starts and fuel moves thru the filter again it collects the crud and packs the screens again after a few minutes..hours sometimes, and the cycle returns until the day arrives where there is so much crap in the can type filter that its plugged forever. $15

FSM will detail the steps to remove/replace. FYI--- you will wear a LOT of fuel unless you bleed the pressure completely off by running eng with pump fuse removed. Even then whatever is still inline will drain in your face.

 

[boomdriver]

Hi. my name is Bruce, I have a 88 c4 5.7 automatic lovelly car i adore it but it has an issue with the fuel system. in heavy traffic after the fan cuts in a few times it seems to faulter like ts starving for fuel, low to no pressure in fuel rail even with filter off the is no fuel pumping through and the thing is if you leave it and let it cool right down it will start up.
Im not sure what it is i have a suspicion it may be fuel relay or even oil pressure switch just wandering if anyone has come across this before and if so where is the fuel relay or is there any knowen fix ... need help here its embarrasing to brake down in the city in a vette everyone looking at me ...

Curious... ?? ??

what are you calling "the filter" that you took off to observe that there was no flow?
'cause whatever it was....it was'nt the filter unless you made a fitting with ferreled ends that fit precisely between the 2 steel lines on the frame.

forget the fuel relay. The car will run with that relay in your pocket. As long as the plugs are on the sender/switch something is completed and supplying power. Besides, if something were d/c it would not run at any time.

 

[mutley]

Boys you are so full of knowledge of this stuff all you say makes good sense and im oing to do all you have said and come back to you. My vette has 112,000 miles but from what i was told by the salesman i bought the car from who just buys and sells vettes apparently it sat for quite some time not used very often by its previous owner so that would sure explain the moisture in the tank and corrosion which im sure will be there, which i will try to collect with a magnet
I did change the filter under the door the first time i unscrewed the outlet to see if there was fuel coming out and there wasnt so i unscrewed the inlet and fuel started to piss out so obviously the filter was blocked so to get home i blew the filter clear from the outlet to the inlet so as to back trac the blockage and put it back together and it worked .. the second time it happened with the same filter off there was no pressure on either side im guessing that the filter in the tank could well be blocked too.
I dont have a pressure tester but i will get one.It seems its a handy thing to have with an older vette with corroded tank. as for the relay after reading your replys the relay is only working till the oil pressure switch is active . when it happens its like as if the car wants to start but is starving for fuel so its definately not electric its for sure fuel
I have ordered online a new fuel pump complete and a filter . i will clean the tank and lines . im pretty sure that should cure the problem but it just feels good to get good advice from knowledgeable people. I own and run a repair garage in Watford london uk but we specialise in clutches and brakes so fuel injection problems are quite new to me but im sure ill fix it. will try to send some pics of my car for you hope it works and hope you all like it .. thanks again..

 

[mutley]

apparently my pics are too big sorry

 

[mutley]

here they are

 

[mutley]

and these

 

[boomdriver]

Boys you are so full of knowledge of this stuff all you say makes good sense and im oing to do all you have said and come back to you. My vette has 112,000 miles but from what i was told by the salesman i bought the car from who just buys and sells vettes apparently it sat for quite some time not used very often by its previous owner so that would sure explain the moisture in the tank and corrosion which im sure will be there, which i will try to collect with a magnet
I did change the filter under the door the first time i unscrewed the outlet to see if there was fuel coming out and there wasnt so i unscrewed the inlet and fuel started to piss out so obviously the filter was blocked so to get home i blew the filter clear from the outlet to the inlet so as to back trac the blockage and put it back together and it worked .. the second time it happened with the same filter off there was no pressure on either side im guessing that the filter in the tank could well be blocked too.
I dont have a pressure tester but i will get one.It seems its a handy thing to have with an older vette with corroded tank. as for the relay after reading your replys the relay is only working till the oil pressure switch is active . when it happens its like as if the car wants to start but is starving for fuel so its definately not electric its for sure fuel
I have ordered online a new fuel pump complete and a filter . i will clean the tank and lines . im pretty sure that should cure the problem but it just feels good to get good advice from knowledgeable people. I own and run a repair garage in Watford london uk but we specialise in clutches and brakes so fuel injection problems are quite new to me but im sure ill fix it. will try to send some pics of my car for you hope it works and hope you all like it .. thanks again..

You cannot clean that filter. It has a check valve of sorts and multiple screens. Its not like a carburated fuel filter. Its throw-away. Thats your problem. I just hope that blowing thru it did not break the screens and allow debris to get to the injectors. Forget the relay....your analysis is not quite correct.If you get 2 seconds of fuel pump operation at key ON....then the relay is fine and the system is working as it should. That 2 seconds can be heard when the key is turned to ON. The oil pressure switch is a back-up device only. The system runs off the relay. When the relay fails the system can still operate when the motor cranks over and builds 4 psi oil pressure. The switch does nothing during normal run. It may function but its function is irrelevant if the relay is working.

 

[air1jpg]

You cannot clean that filter. It has a check valve of sorts and multiple screens. Its not like a carburated fuel filter. Its throw-away. Thats your problem. I just hope that blowing thru it did not break the screens and allow debris to get to the injectors. Forget the relay....your analysis is not quite correct.If you get 2 seconds of fuel pump operation at key ON....then the relay is fine and the system is working as it should. That 2 seconds can be heard when the key is turned to ON. The oil pressure switch is a back-up device only. The system runs off the relay. When the relay fails the system can still operate when the motor cranks over and builds 4 psi oil pressure. The switch does nothing during normal run. It may function but its function is irrelevant if the relay is working.

Bruce,
It always puts a smile on my face when I hear/read about a Corvette fan in the UK, I think it's great!

Have you heard about the CCCUK Corvette club in the UK? CCCUK -
Boomdriver is correct, the fuel filter on your vette is a throw away and should not be cleaned and used again. Have you purchased a FSM? (Factory Service Manual from GM) If not, you can probably find on on Ebay for about $100 US. The service manual has invaluable information on every system on your vette and it is model year specific.

 

[mutley]

thanks boys. no i hav't heard of the cccuk but i will look them up .. I know thw filter is throw away but i was 92 miles from home on the highway no one around or anything around and i just bought the car and was driving it home that was the first time it happened ...

since i was 9 i always said i would one day have a corvette ive been admiring them all my life now that i own my own business and i can afford one i got 1. It was'nt my first choise i wanted a 1972 stingray with a t top but maybe in a few years. God they turn heads. since i got it some of the people i know have said the c4 is not like the corvette's they know and that its not a real corvette so on , i say its looks good, sounds good feels good , it says CORVETTE on the back and i love it and its all mine.

 

[John Robinson]

You might tell your friends that think the C4 is not a real car the following. When they first started to be raced here in the USA they were so superior to the Porsch and BMW's of the time that they were going to withdraw from racing if they had to compete with the Corvette. One of there comments was that the Corvette drivers in the rain could just drive by them into a corner while adjusting the radio and jump into the ABS brakes and out corner them. This prompted the sanctioning body to establish a Corvette only series for several years until the they caught up with the Corvette's performance. Another tid bit of information I find interesting about the C4 is the .98G laterial cornerning force on the tires they had back in 1984 along with 0 to 60 stopping distance of 116 feet.

Back to your original proablem. I appluad you for being able to get too the filter along side of the road and having the tools to work on the car. Having changed that filter myself I know that was not easy. I think it is preatty evident that you will find corrosion in the tank when you pull the fuel pump because of how the filter got clogged with driveing the car.

 

[air1jpg]

thanks boys. no i hav't heard of the cccuk but i will look them up .. I know thw filter is throw away but i was 92 miles from home on the highway no one around or anything around and i just bought the car and was driving it home that was the first time it happened ...

since i was 9 i always said i would one day have a corvette ive been admiring them all my life now that i own my own business and i can afford one i got 1. It was'nt my first choise i wanted a 1972 stingray with a t top but maybe in a few years. God they turn heads. since i got it some of the people i know have said the c4 is not like the corvette's they know and that its not a real corvette so on , i say its looks good, sounds good feels good , it says CORVETTE on the back and i love it and its all mine.

When I was shopping for my vette, I was looking to get a C3 at first because I like they way they look. Out of the C3s I could afford (79-82), I found that I could get a C4 with quite a bit more power and features for the same amount of money as the C3s I was looking at. I still love the C3s and I still like the looks of them better, but the C4 is a overall better vette out of the two.