Car is Runing Rich 1000-1900RPM's?

[Lee'S 1997 Z28]

Hi Guys and Gals!

I have a 1997 Z28 with 79, 078 Miles on the Clock.

Problem: Car runs rich and puffs black smoke 1000-1900 Rpm's and Spudders or pops in the exhaust.

No Backfires in the Intake!

Maintenance Performed:
New Plugs and Wires (GM)....New OptiSpark (GM)......New EGR Valve (GM).....Cleaned the Throttle Body and Put New gaskets in it(GM)......Unhooked fuel pressure regulator to see if fuel was leaking back through Vacuum line it wasn't.......

Fuel Pressure: 46PSI Key on Engine not Running.....40PSI at idle....45PSI WOT.....

What your guys advice????


Thanks Lee!

[Lee'S 1997 Z28]

No one. Not even one reply!

[Joe 1320]

Well, it's going to be tough to diagnose without having hands on. A scanner would be helpful to see exactly what the computer sees. An over rich condition could come from:

Leaking injectors
Ruptured diaphram in the pressure regulator
Exhaust leak prior to the 02 sensor
Ignition failure
02 sensor(s) on the way out or contaminated
faulty coolant temperature sensor
faulty TPS
incorrect or corrupt PCM program
faulty MAF
faulty MAP

Like I mentioned above, a scanner is a good investment. To be able to read what the ECM sees will cut your dignostic and repair time by more than half. Without it, all we can do is hypothesize.

[Lee'S 1997 Z28]

Thanks Joe!

What scanner would you recommend that I buy that would be the best.

Thanks Lee!

[Joe 1320]

Originally posted by Lee'S 1997 Z28
Thanks Joe!

What scanner would you recommend that I buy that would be the best.

Thanks Lee!

Snap on. Be prepered to pay a little more, but it's an exceptionally high quality unit. If that's a little much, autozone carries an Auto Xray for OBDII that runs under $150.