Hey! Nice to have a big forum for third generation f-bodies!

I haven't seen this discussed before so I'll start a new thread.
I have an '88 Firebird with the 2.8L V6 motor and have a problem which keeps me from being able to drive it for very long. The motor starts fine and will run with no problems, but when it gets up to normal operating temperatures it tries to (and sometimes does) stall. The oil pressure drops very low, somewhere between 15/25psi and the RPM drops as the motor hesitates to stay running. Sometimes the battery voltage drops down to nearly 8V and I have to rev up the motor to charge it back up. I've never seen or heard of this happening before, although I haven't worked with the 2.8L before either. Does anyone know what might cause this to happen? Is this a common problem with this motor?

Thanks in advance!

 

welcome to thirgen.org. sounds like you have a eletrical supply problem, have you had or have you checked the alternator and battery? that'd be where i started from your description. another thing to look at, if i didn't quite understand what you're saying is the ignition module, replace it or have it tested. they tend to fail hot.

 

Metal,

I'm guessing that you have an MPFI fuel system since you have an '88. Correct me if I'm wrong on that count.

When the engine begins to stall, can you always save it by adding throttle? If so, chances are your ignition system and HEI switching module are still working (maybe not correctly, but still working). The oil pressure and system voltage problems are likely the result of lost engine RPM, however, the system voltage still shouldn't drop below battery voltage unless you have a connection issue.

You may also have an idle speed control problem or closed-loop mixture control issue, or a base timing problem, all contributing to the problem.

A little more diagnostic data would be helpful:

* Are there any error codes?

* What is the engine idle RPM when the engine is warmed and out of gear?

* What (if any) modifications have been done to the engine?

* Does your engine start normally when cold, or is there hard starting?

Just a few more pieces of information and we should be able to point you in the right direction.

Incidentally, Welcome Aboard!

 

ede:
The battery is brand new, but I'll check the alternator and ignition module.

Vader:
Yes, I have the MPFI system.
The engine will run fine if I increase throttle.


Are there any error codes?
I should have checked that before I put it in the detail shop. I should have the car back either tomorrow or Monday, I can update you on the codes.

What is the engine idle RPM when the engine is warmed and out of gear?
When the engine is warm and presumably goes into "closed loop" operation, it is anywhere from 200-600 RPM (600 occurs when it tries to keep itself running).

What (if any) modifications have been done to the engine?
Well I just bought this car, but I have checked it over and see no major modifications.

Does your engine start normally when cold, or is there hard starting?
Yes. Like I stated before, it starts and runs fine when cold.

Again, thanks for your help!

 

I had a had with this and found the vacumn control valve for the fuel tank was bad (near the charcohl canister). I replaced it but still occasionally have the same problem.