Atl_monte

I have a 1992 Corvette that isnt gettign fuel to the fuel injectors, pushed the check valve on the rail and nothing, took the line to the filter loose, no fuel.

I would liketo check the fuel pump relay before I just automatically assume its the fuel pump, but cant seem to locate the fuel pump relay. Anybody care to chime in with a few ideas/suggestions?

don hall

May help (?):

http://www.digitalcorvettes.com/foru...d.php?t=131407

Atl_monte

helped a little as to how to systematically trouble shoot an issue but I'd still need to know where the fuel pump relay is as I dont believe it is on the firewall on the 92, mine runs along as you continue to spray starter fluid in the intake.

But did test pressure on the shrader valve by the injectors and found none.

vetteoz

Fig 23

Purple92

Getting to the Fuel Pump Relay is a PITA (ask me how I know this). Putting the whole mess back in place is also a bit on the dificult side.

In the LT1 equipped C4's the fuel pump is powered in one of two ways - 1) during start the PCM turns on the fuel pump via the fuel pump relay - and runs it for about 2 sec (or when cranking). 2) when you have oil pressure, the oil pressure switch sends power to the fuel pump. Personally - I think it's a lot easier getting to the oil pressure swtch at the upper back of the motor. I believe the orange wire (Pin C) is the power feed, and the red wire (Pin D) is connected to the fuel pump. (I beleive you can also jump power to the fuel pump though the 10 Amp Fuel Pump Fuse - which the FSM shows as After the oil pressure switch and Fuel Pump Relay - but I'm not 100% sure of that).

Do you hear the fuel pump run when you turn the Ignition to "ON". Normally you can hear it - if you can't you may well be looking at a fuel pump replacement.

GOOD LUCK !!!

pcolt94

I think this is a better approach. The relays really don't go bad very much. It is easy to pull the pump or just check for power if necessary by getting to the connector of the pumps power in the rear of the car. Four screws for gas cover and remove rubber and there's the connector.

Atl_monte

did a little work in the garage today, tested the fuel pump and relized it was bad, repalced it but the new one still isnt getting power(only works hot wired) the sending unit(purple wire) is getting power but not he fuel pump wire(gray wire)

pcolt94

Re-check fuse #14. Then makes the checks purple92 suggested. It's possible you blew a fuse under the hood in fuse block 1 but it's doubtful.

Are you sure no power is going to the pump. Just a double check to make sure the pump has a good electrical connection and is grounded. Just a suggestion.

Atl_monte

yes the gray wire at the pump harness is showing no currrent, but I will check the fuses, the pump works if you apply direct current to the gray wire

pcolt94

If you check for voltage at the gray wire you will not have it if the engine is not running. It is only there for the first 2 seconds when the key is turned to the ON position. So you have to monitor as you turn the key to ON.

Once the engine starts, the relay is held closed by the ECM and voltage is also sent to the pump from the switch which is activated by oil pressure (redundant power).

Another simple test to try is to connect your voltmeter to the gray wire and crank the car. You should be able to build up enough oil pressure to close the switch. Might give you additional information and a clue.

Another interesting test is to run the pump with external power. Then try to start the car and see if it runs. At the same time monitor the gray wire with a voltmeter and see if voltage appears on it. If it does, that might mean the oil switch is working and the problem is in the relay circuit.

If no voltage appears on the gray wire when the engine is running, then I would check the fuses under the hood in fuse box 1.

You get the idea.

Atl_monte

thanks for all the input everybody got the fuel pressure issue addressed, had to replace the fuel pump, and after a few on & offs of the switch finally got itfired up, now I have to address the idle but I'll do another post for that