crowz

If its in that circuit then shorting the 2 wires together that are on that plug should turn on the fuel pump all the time and keep the car running.

WW7

Here is a thread that may help you understand what is going on with your fueling problem.."Hooked on Vettes"also explains how to check the fuel electrical system..Hope this helps.....WW

https://www.corvetteforum.com/forums...e-problem.html

J H

Not likely electrical. Definitely sounds fuel related. Look at fuel filter, fuel pressure regulator. Remove the fuel line going to the fuel rail and turn on the ignition switch. Fuel should squirt out fast and with a strong steady stream. Or, disconnect the fuel line at the fuel filter on the engine side (after the filter). Turn on the switch and you will get a lot of gas squirting out. If there is no gas coming out here or the stream is weak, look at the filter, pump, in-tank sock/filter, etc. If gas does come out strong, look at the pressure regulator.

C4SS

Thanks everyone again, as much as I love to, I wasn't able work on the problem today.
I did get a look at the two oil pressure units, but not much of one. Why would a GM
engineer place those that hard to get at? To keep us from working on our own autos?
I did start to disconnect the fuel line at the fuel rail, and got a high pressure spray
even without the key on. Same result when pushing the Schrader valve. I'm sure I had a proper connection of the test gauge, but maybe I didn't bleed off the release/
overflow tube long enough. I never got fuel to come out of it. I'm cleaning each connection and testing after each to see if problem is solved. Did anyone see that I do have my two dist. wires correct, and not mixed up?

C4SS

The fuel pump has new sock. Is there an odometer rollover reset
switch on Vettes, like on Ford PU's?

crowz

Nope.

Shorting that pressure switch's wires I showed you will force the pump to run.

Just unplug it and use a wire to jumped the two connectors in the plug. You don't have to remove the switch or anything.

Its the next best test to do.

C4SS

Well, I don't hear anything while jumping the pins. Key off
or key on.
What is the function of the little grey vacuum bell in the
pic? Where does the line go that is missing in pic? It fell into
the abyss when it was unplugged. Can't see it now. I love the
room to work on these cars.
Can anyone tell me the socket size to remove the oil pressure
switch? It is barely visible in photo.

Cliff Harris

You should be able to make the fuel pump run by jumpering the orange and red wires together in the oil pressure switch connector. The ignition does not have to be on to do this.

That's the vacuum check valve. It maintains vacuum on the cruise control and the HVAC system. The missing connection goes to the HVAC system inside the cabin. You will not be able to control where the air comes out with that hose disconnected.

Your oil pressure switch is not the problem.

J H

I had a problem similar to yours a few years ago. My 85 just shut down and would not restart. The problem was with the wiring inside the fuel tank. The wiring connections had gone bad and were touching. I re-did the connections and the car started right up. I had a little pressure at the fuel rail as well. Obviously not much, but enough to make me think the pump was working. It was not. I replaced the pump and several other items to no avail. Thoroughly examined the wiring and found the problem. I never would have thought this was the issue, but it was. I worked with the car for about 1 1/2 week before I found the problem.

crowz

Use a volt meter and see if there is 12 volts on the orange wire. Key on or off doesn't matter. The orange wire should have power all the time.

This is on the oil pressure switch connector.

tlxxtl

My 89 does the same thing, but only when the fuel level is hovering around 1/4 tank or less. The last time I added $10 of gas and it started right up.

C4SS

OK, I got a successful ground test on the oil pressure switch "wires",
guess where this shade-tree mechanic first tested.
I could hear the pump run and the furl surging into the rails. I plugged
the wire back in and covered the vacuum exposed port with tape. The
engine starts right up as before, and quits just as before. Still stumped.
It's like there is a command to computer to shut down engine.

C4SS

So, now after rereading all posts, I'm thinking fuel regulator or could it
be the adjustment of TPS?
This problem started while driving on Interstate. Engine quit, wouldn't
restart. AAA took it home. Code 32 flashed. I replaced EGR valve. that
brings me to where I am now. No code flashes after 12

crowz

Umm while you had the fuel pump manually running like that you were supposed to crank the motor and see if it ran ok

By having it manually running the pump with that plug jumpered and then cranking it up your eliminating the possibility that the pumps cutting off and causing your problems.

C4SS

OK, thanks for holding my hand through this.
I jumped it over, heard pump, and rails filling,
wife started it up and it ran great for the usual
short time and quit. Tried it several times, Same.

J H

Well, time now to think electrical. What about the ignition module? It could be running just long enough for that to heat up a bit and fail.

C4SS

I replaced that too.

C4SS

Could this have something to do with the injectors?
Do they ever need priming?
Is there a maintenance cleaning necessary periodically?

Or is the fuel regulator still questionable?

Could the TPS need adjustment?

crowz

Unplugging the tps and cranking it is the test to eliminate the tps as an issue. If it starts then dies with the tps unplugged its not the tps.

Also the injectors do not need priming.

I hate throwing parts at it but the fuel pressure regulator could be the problem.

C4SS

Thanks crowz, it does start with TPS disconnected, same.

I have resolved to replace the fuel regulator next, even though
it's $100+ and I have to remove the plenum again.