I try to drive my 82 vette on the weekends but with all this rain lately here in Florida, I have not driven it in 3 weeks. I went to start her up today but she did not. I checked all the fuses but they were all OK. I decided to pour a little gas in the throttle body and she turned on for a few seconds so I am asuming the Fuel Pump or the ECU. Can anyone guide me in the right direction to determine the exact problem?

 

Do the injectors squirt fuel when cranking? Do you hear the fuel pump running for a few seconds with the ignition on and does it also un when cranking (hard to hear)

I would check the fuel pump relay first (since you already checked the fuses), it's on the passenger side backwall under the storage box liner.

While you're in there, also check the big metal box in the plastic holder with the fiberglass reinforced tape holding it together, that's your wiper control module, usually the tape dries out, the module falls out it's plastic holder and shorts on the jack, this has nothing to do with your problem but it's a nice while I'm at it job, those control modules are hard to find

 

Do the injectors squirt fuel when cranking? No

Do you hear the fuel pump running for a few seconds with the ignition on all i here is a 2-3 second clicking sound. I think it is the relay.

does it also on when cranking (hard to hear) havent really paid attention. i would think i need a second person to stand in the rear

I would check the fuel pump relay first (since you already checked the fuses), it's on the passenger side backwall under the storage box liner. since the relay is clicking, can i assume its working or should i use a multimeter to test it?

While you're in there, also check the big metal box in the plastic holder with the fiberglass reinforced tape holding it together, that's your wiper control module, I recently replaced the wiper module. I found it at a local Corvette repair shop.

 

Okay, that pretty much leaves the pump feed or the pump as the culprit, if it is running (it can be hard to hear) it may be a clogged strainer (pre filter on the pump) or a completely clogged filter. if you follow the wiring harness that comes from the top of the fuel metering unit/filler opening on the tank there's a connector, disconnect and check for 12V at the fp feed, I don't remember the wire color coding, i think it's tan/white at the metering unit and blue on the rear car harness...but there are only 3, one fp feed, a ground and the 3rd one is fuel level.

If there's no 12 v when the relay switches (and it only activates a couple of secs after turning the ign. on ...when testing turn ign off for 30 secs before trying again or the ECM won't activate the relay again) check at the relay. Is there 12V (after turning ign. on) on the tan/white wire? If yes, the problem is up ahead possibly in the fuse box (fuse is in this tan/white wire circuit on the fuse box) if not, the relay may not get a 12V ignition switched feed, this is a red wire and there's 12V on it whenever the ignition is in the on position.

If you need a wiring diagram go here
http://www.crossfire.homeip.net/faq/diagnostics.html

My money is on the pump being shot since this came on after a longer stand still. Now if it turns out to be a defective pump, you need to remove the fuel door assembly and then remove the 8(?) bolts that hold the fuel filler/metering unit to the top of the tank, removing the metring unit from the tank and then getting it through the hole in the rear deck takes some twisting and trning, it's a bit of a puzzle but it should come out without paint damage.

If you replace the pump, get a DELCO unit, preferrably the 85+ pump since the stocker barely puts out the needed flow and psi in new condition.

Here's an article on replacing the pump
http://www.crossfire.homeip.net/cfte...ID=18&CAT_ID=1

One thing you also need to do when replacing the pump is clean out the gas tank, often a bunch of water collects in the gas tank and sits at the bottom, this kills fuelpumps when they are submerged since water doesn't lubricate and it can lock the pump up due to corrosion

 

thanks for the great info. I will dedicate time to do this next saturday.

I really appreciate the help.

 

Ok, im stumpted. I disconnected the the FP connector under the fuel door assy. I tested the output of the connector, tan/wht and black and there is 12v while priming and when cranking. I assumed since there is power, the FP is shot so i replaced it. The car still does not start. I connected the FP direclty to the battery and the car turned on. I reconnect the connector and the car does not start. Any ideas? Could the connector be bad?

 

here is what i did next. I stripped both the positive and negative cable before the connector and disconnected the FP from the connector. when i try to start the car, i get 12v both prime and crank. when i reconnect the the FP and try to start the car again, i do not get 12v at all so i am assuming there is a short somewhere. anyone have any ideas?

 

Did you check for 12 volts at the battery when cranking? Your battery may not be holding a charge. You will probably need someone to help you check things out, but if you are loosing power at the pump connection while cranking but not blowing a fuse, I would bet you have a bad electrical connection somewhere between the battery and the fuel pump. Do you get 12 volts while cranking on both sides of the fuel pump relay contacts? How do the wires look going into the fuel pump relay socket? How do the contacts on fuel pump relay and plug look?

 

Where do i find the fuel pump relay? I believe it is in the passenger compartment but dont know exactly which one it is.

 

According to the second post on this thread, the fuel pump relay is on the passenger side under the storage box liner. I'm much more familier with f-body cars than Vettes, but G.M. had a bunch of relay problems on '82-85 Camaros and Firebirds. After 85 or 86 they changed the relay and socket design. The Vettes from those years may have had similar problems.

 

you know a bad relay can create an open circuit stopping you from getting any juice....

 

I looked for the relay as described by Twin_Turbo, but don't know which one it is. I see three units in the compartment. If i am not mistaken, the unit on the left looking in from the top is for my wipers. The unit in the middle has two connectors and is metal and the unit on the right is plastic. Which one is it? Both these units have a yellow wire coming out of it but looking at my schematic, there is no yellow wire on the relay.

 

It's the black plastic one, the óne with the metal housing and white/yellowish base is your power antenna relay

I don't know what schematics you have but here is the entire enchelada and no yellow wire in this one

 

nice

 

This is what the relay looks like:

 

OK, I found the FP relay. It was behind the ECU. I followed all the steps in the Fuel System Diagnosis in the service manual. I got to the point where it states "connect test light between harness connector CKT 120 (blue wire) and CKT 340 (orn wire).

What harness connector are they talking about. Neither the FP relay nor the oil pressure switch have a blue cable.

PS. I connected a test light directly to the FP fuse and am not getting any power to the fuse at all.

 

behind the ecm? do you mean on the back of it (bolted to the same bracket)? If so, that's the ESC, not the fp. relay, the relay is next to the ECM bolted to the wall.

There's a blue wire just before the level sender harness, so at the tank..not at the relay (running from the fuse to the pump, before that it's tan/white and after the connector it's blue, then at the tank connector it's tan/white again.
The FP fuse is located AFTER the relay and pressure switch so if there's not 12v there it can be either, is ther e12V when you turn the ign on or is there never 12V? There's only 12V w/ ignition on if the relay is working, there's only 12V from the pressure switch if the engine is running w/ proper oil pressure. Look at the diagrams it's all in there.

 

There is never 12v at the fuse. Where can I find the harness where all the tan/white cables from the relay, ECM and oil pressure switch all meet? I ran a cable from the FP fuse to the battery and the car started, so everything after the fuse is good. I then connected the tan/white cable from the FP relay harness and the tan/white cable from the oil pressure switch harness direclty to battery but the car did not start. Shouldn't the car start? Is it possibe that my ECM is bad? I noticed from the diagram that there is a green/white cable going from the relay to the ECM.

 

Your fuse is between the relay and the pump if I'm reading the schematic correctly. The fuse is powered by the orange wire from the battery through terminal "E". If you have power at the green/white trace wire on terminal "C" and a good ground on the black/white trace wire at terminal "B", the coil for the relay should energise. #1 Do you have power all the time at terminal "E"? #2 Is the relay energising? If the relay is energising, and you have power at terminal "E", but nothing at the fuse, you either have a bad relay or a bad connection between the relay terminal "A" and the fuse.

 

#1 Do you have power all the time at terminal "E"? YES
#2 Is the relay energising? YES

If the relay is energising, and you have power at terminal "E", but nothing at the fuse, you either have a bad relay or a bad connection between the relay terminal "A" and the fuse. I agree, but shouldn't the fp run if I jump the orange wire terminal E with the tan/white wire terminal A? When I try this, the pump does not run. By process of elimination, I guess there is a bad connection between the relay terminal A and the fuse. Can I assume this?