Just picked up a '91 Z that was in need.
Has some running issues.
Just spent my first day looking over the car.
Idle is constantly searching up ad down.
While driving it will die when you push in the clutch.
Loses power bad when reving up.
Check engine light stays on and occasionally flickers.
Computer controlled cooling fan runs constantly.
Will not flash trouble codes.
Light stays on when checking for codes.
Computer has been replaced at one time.

 

ECM and possibly one or more sensors are probably bad. Car is most likely in limp home mode (hence the running bad and SES light).

 

make sure they didnt replace the ECM with a automatic one. If you get the #'s off of it they should be able to track it down to see where and what it came off of.

 

The computer number is 16198262.
According to Standard Ignition Products catalog it fits:
90-92 Camaro 5.0-F engine
90-91 Camaro 5.7-8 engine

Prom should be different for auto and manual.
Also discovered that it has an ADS Superchip in it.
The AIR system has been removed.
Don't know what affect that had on drivability.

The speedo doesn't work either.
Can't figure out why it won't flash diagnostic codes when I try to pull them.

 

if the ADS is a piggy back, drop it off and see how she runs. also, check for a vaccum leak.

 

That was next on my list along with cleaning the IAC valve.

 

Pulled the super chip today.
Car now has a working speedo, idles, fan quit constantly running, and will go into diagnostic mode.

Still goes real flat revving up.
Took a trip around the block and it has not thrown a code yet.
Feels like the timing is being pulled out or it is starving for fuel revving up.

 

Faulty/bad fuel pump and or fuel filter

OR

Detonating really bad and ECM is retarding the crap out of the timing.

OR

bad gas, try running 93 octane from a good gas station

OR

pick-up module in distrib. is going bad



............ just some ideas to look into.

 

- check base timing. - as in unplug the est, and check w/ timing light. start around 6(stock). Many people crank the timing on these cars because..."it'll make it faster"...to much timing can easily make it "faster" to the trailer...

 

Guy who had it before me replaced the distributor and fuel filter.
I have been easy on putting too much gas in it for the fear of it being the fuel pump.
I have put 93 in it and it was almost empty when I got it.