Hello from a new member. I currently have a 1995 Coupe as well as my original 1968 427 Coupe. Before that, I had a 63 Coupe, and then a 65, so I am not new to Corvettes.

I have a starting problem I wonder if any of you can shed light on. I did not drive my 95 this past summer, so it has been sitting for at least 6 months without being started. When I went out to start it a few days ago (after charging the battery, which was dead) it would not start.

After adding 5 gal of new gas, it still would not start - turns over normal, but will not start. After checking several things, I sprayed some ether in the tube between the filter and throttle body and it started right up, but died after the ether was gone. I tried this a couple more times with the same result.

So I have spark, and the security system is happy - just not fuel from the injectors. When I first was trying to start it, I could hear the fuel pump come on and then stop. However, that is not the case now. So I think I need to check the fuse for the pump, and then the fuel pressure if I can get the pump to run again.

However, since I had normal fuel pump operation initially but could not start it, I am wondering if there are any sensors that might have gone bad and caused the computer to shut off the injectors. Anyone know the C4 well enough to shed any light on what might be wrong?

 

Check the fuses for the injectors (there are two fuses in the panel at the pass side end of the dash). If they are good then get a noid light and see if the injectors are getting the pulses from the PCM. I am sure you know where the schrader valve for checking fuel pressure is, so that is also easy to check.

 

Let's assume you have spark and the ignition system is OK.

Before you go off with the complex stuff, start at the beginning. You heard the pump run. It should run for 2 seconds every time you cycle the key from off to ON. If it is not happening now, first check the pump fuse #14, 10 Amp (no fuse in #15).

Check the fuel pressure. But if the pump is not cycling on the key every time, I rather doubt if there is any pressure. At that point I would consider the pump being bad.

Probably easiest way to check that is to check for 12 volts (pump power) on the gray wire at the rear of the car on the pump connector. If you have 12 volts when the key is turned to ON, then pull the pump and check it out.

If you have spark, the opti is working and probably clocking pulses for the injectors but you can check it with a noid light. But no need to go there before you check fuel pressure or resolve the pump issue first.

 

Thanks for the replies! That gives me something more to go on. It has been raining here (Dallas, Tx area) for the past several days and it was only 36 this morning, so I plan to wait until it warms a bit before trying again.

I definately have a fuel problem, but I did have one more idea in the middle of the night when I woke up - since the car has been sitting for an extended time with not much gas in it, do you think it is possible the tank has accumulated enough water from condensation to cause it to be pumping water instead of gasoline?

When the tank is mostly empty, moisture laden air is drawn in and as it cools the water condenses out. then when it warms, some of the air is forced out - only to be replaced with more moisture the next night - just a thought....

I think my plan will be to check/change the fuse on the pump and when I get it running again, I will check the pressure and draw a sample of fuel to see if it really is gasoline, or mostly water - of course, if it will not develop pressure, then I will have to replace the pump which will mean draining the tank (I think the pump is in the tank, is it not?). The pump was acting normal to start with, so at least there is a chance it is the fuse...

Can you think of anything else I should check?

 

Yes, the pump is in the tank and access is through the top (easy). If it was sitting outside and the drain in the fuel fill 'bib' was blocked then it is sure to have water in the tank.

 

It's outside, but under a car port - it's protected from vertical rain, but wind driven can get to the car. OTOH, this has been one of the dryest summers on record here.

Access from the top? I can't believe it! On my 68 I had to pull all of the spare tire stuff just to get to the bottom of the tank...

 

Wow, that was easy! Pulled the pump and checked it: ohms seemed OK (1.2), but when I applied 12 volts to it, it just sat and looked dumb... The motor may be good, but the pump is seized. Cleaned the tank out and put in a new pump, and the car runs fine. Thanks, guys, for your help!