hopeitwillrun

i just bought a 1987 corvette that has sat for 2 years. I put a new battery in it and cranked it but it wont start. There was spark at the spark plugs but no smell of gas. It will run shortly on a shot of starting fluid and die out right after. I am suspecting the fuel pump is failing because i hear no humming of the pump when the key is turned to the on position. All i hear is a click from the back of the car. What tests should i run to determine if it is the pump or if sitting for so long has caused another problem? Any troubleshooting hints would be helpful, thanks.

SJW

A fuel pressure gauge connected to the fuel rail will verify the presence (or absence) of fuel pressure. Presumably, based upon the symptoms, it's absent. If you have no gauge, you can try momentarily depressing the schraeder valve to see if any fuel squirts out, but do so with caution, for obvious reasons.

If there's no fuel pressure, it's probably either the pump or the relay. I'd begin by checking for drive voltage at the connector above the fuel tank.

The best thing you can do for yourself is to buy the factory service manual for this car. You can order it direct from Helm, Inc which is the company that prints them for GM, or you can surf EBay for a decent used copy. Just make sure it has the red cover -- if not, it'll be a preliminary release, which will not be as complete and accurate as the red-cover version.

The fuel pump is very easy to replace on a C4. It all comes out the top, and can be done easily in less than 30 minutes. There's no need to drain the fuel tank for this operation.

Be well,

SJW

ms85corvette

Unless in those two years you got water in the tank.

If you go and change the fuel pump, I'ld suggest going ahead and draining the tank. That way you know when you start it up again, that all the fuel you are pumping is good, and don't forget to change the fuel filter.

STREETKNIGHT

Theres also a mix u can add to the fuel tank to remove the water from the fuel sorry, can't recall the name but check with the supporting vendors or do a google search. Anyway, you can do that as well, but Do something.

I too bought an 87 that had sat for 2+ years. Had to replace the fuel pump shortly after purxhase. Piece of cake

Good luck

AGENT 86

http://members.shaw.ca/corvette86/En...ButWontRun.pdf
http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf
http://members.shaw.ca/corvette86/Ig...System-EST.pdf

rick lambert

If you're not hearing the pump prime I would suspect the fuel pump
relay MAY be shot-cheap part about $12. Hopefully you checked the FP fuse? You can also check the fuel pump by applying battery voltage to terminal G on the ALCL.After two years you can almost bet the fuel has soured or has water in it-Heat is a product I have used to help remove moisture from the fuel-but there are alot of products. I do suspect the fuel pump though-because even if the relay is shot the fuel pump activates (runs) after cranking produces 4# of oil pressure.
And replacing the fuel pump is possibly the easiest thing on C4s to replace-including tail lights. Good Luck.

hopeitwillrun

i still havent had any luck with all the good advice. I checked the fuse panel and there was no fuse for the fuel pump. Any idea where it might be the manual was no help. Then i tried applying voltage to the G terminal of the ALCL, it still didn't turn on. Next i jumped the voltage from terminal D to E on the fuel pump relay and it didn't turn on. Replaced the relay didn't turn on. Replaced the pump, still didn't turn on. This is where im stuck. There is power to terminal D and B on the relay but nothing to the pump. I hope this car isn't a lost cause but im losing hope.

AGENT 86

There IS a fuel pump fuse. I think mine uses the letters FR or similar. If in doubt use a ohm meter and check every fuse.

Find the fuse

AGENT 86

Try the bottom right fuse when looking at the fuse panel

hopeitwillrun

Thanks for replying again, i found the fuse and put a test light on it and there is no power to that particular fuse. Im confused why the relay is recieving power if the fuse is not. I assumed the relay was after the fuse in the circuit. Once again im stumped.

CentralCoaster

No. The 10amp fuse is downstream of the relay. If you have the 4+3 by chance, swap it with the overdrive relay and see if that works. Otherwise, try tapping on the relay. It's on the firewall left of the brake booster... if you have a 4+3, the fuel pump relay is on the firewall, the overdrive relay is in front of it. Same part number. Also check the wires to the plug on the relay, the insulation shrinks back and can short out and become a fire hazard.


The car should start eventually even with a bad relay. When you crank it over a few times, it should start the fuel pump as soon as you get 4psi or so of oil pressure.

hopeitwillrun

it runs finally but won't idle. I have to keep the engine around 2000 rpms so it won't die. The other concern now is the coolant temp got to 200 degrees fairly quick, i was wondering how hot it shoudl run and why it wont idle.

CentralCoaster

You'll have to go through and check your base spark timing, reset your IAC and base idle screw, and check for vacuum leaks. This is all assuming your fuel system isn't the culprit.