ShadeTreeJW

1990 Corvette Engine stalls at 3500 rpm


1990 Corvette, factory stock. When engine is cold, in neutral or when driving, 4500 - 5000 rpm can be realized. After the engine warms up, the engine stalls at 3500 rpm, in any gear. On the highway in 6th gear, step on the gas and it seems to slow down.


Fuel: I have replaced the fuel pump, fuel filter and injectors. I installed fuel pressure gauge and the pressure is maintained from 36 - 44 psi, depending on acceleration. I have not replaced or tested the fuel pressure regulator. The fuel pressure regulator is located under the Plenum and very difficult to test.


Spark: I have checked the spark plug wires, the HEI distributor - rotor, cap, ignition module, capacitor, pickup coil and vacuum advance. New E-3 spark plugs. Have changed the rotor, cap, coil and ignition module.


No change.


I have no experience with any TPI, just know that there a lot of sensors, along with the ECU.


I do have a CarTech Chevy TPI Guide book and a GM 1990 Corvette Section A - Electrical Diagnosis Service Manual.


Thank you for your help !!!!!
JW

MrWillys

Pull the vacuum hose and see if it smells of gas on the regulator. What injectors did you use?

ShadeTreeJW

Pull the vacuum hose ? Do you mean the fuel regulator vacuum hose ?


I can't reach it.


Injectors are reconditioned Bosch 22lb injectors for a 5.7l TPI

MrWillys

You can't reach the hose just under the map sensor? What color are the injectors?

ShadeTreeJW

Will look for a hose under the map sensor. I only looked at the back of the TPI, my fuel pressure gauge is in the way.


Color of Bosch injectors yellow.


Will check for the hose this Monday.

MrWillys

0280-155-700 or 0280-155-710 will be a number on those injectors. You may be a bit lean. Which are they?

ShadeTreeJW

Not sure, will have to check. Corvette is at shop, can not check until Monday.


Will get back to you then.

ShadeTreeJW

Bosch Injectors are Yellow - 0280-155-700


Checking catalytic converts


Engine over heating, replaced thermostat , going to replace water temp sending unit


Thinking of replacing the ECU. #01227727

MrWillys

That injector flows 20 lbs.

http://witchhunter.com/flowdatapix/b0280155700.jpg

You can reset your flow rate to 20 lbs? You can confirm this yourself with a scanner. Your BLM counts are running in the 150's and the ECM is adding as much fuel as it can.

ShadeTreeJW

I don't have a scanner, do have the pin configuration for display of codes. OBD-I scanners are not finically reasonable for just one Corvette.


The Corvette was stored for 18 years by the first owner, second owner only used the Corvette, "on sunny days for short trips". Corvette looks like it just came off the showroom floor, with 42,250 miles.


Current focus is on the catalytic converters. Running a heat check, example, 400 degrees front and 100 degrees back, would indicate a catalytic converts are restricted. Am going to try to clean them, with hot water and soap, before replacement. Just to see if this works or not.


Ordered a new ECU, will take 7 - 10 days for delivery.


Radiator boiling over, is a mystery to me, as this is something new. Replaced thermostat, going to replace coolant temp sensor. Radiator electric fans work normally. Will keep monitoring the boiling over problem.


There are several problems with the Corvette, oil pressure gauge doesn’t work, dash did not work, then started working on its own, now flickers on and off, radiator boiling over, alarm didn’t work and now does.


Due to the Corvette being stored and not being used, I think that there is a problem with oxidation in the wire connectors. Example, when I cleaned all of the wire connects on the terminal, located behind the battery, some things that didn’t work, worked and other things started to cause problems.


Don’t have all of the answers, but given time I will.

MrWillys

Good looking car. If you're ever in Reno bring it by and I'll connect it to a laptop for you.

DanielRicany

Check ignition timing