242turbo

I have an 89' GTA with a L98 TPI motor. It is running super rich, sometime very hard to start. The EGR has been deleted, does the computer need to be retuned, chip replaced, or is there some kind of adjustment I need to make?

TransamGTA350

iTrader: (2)

Removal of the EGR (provided everything has been properly blocked off and sealed) will result in a check engine light, but it will not cause it to run rich. Yes, you would need to burn a new PROM chip to delete the EGR from the computer, but that is not causing the pig rich condition.

You really just need to go back to basics and make sure everything is set up per specs and start ruling things out. Is there a check engine light on and have you checked for stored codes? Is this a new issue that just came up? What injectors are in it? Stock, larger? How about fuel pressure?

Tuned Performance

iTrader: (92)

Besides the above mentioned, check fuel pressure drop after prime.

sofakingdom

iTrader: (1)

Check the coolant temp sensor and its wiring. If the ECM is being told it's -200° out, it's gonna dump a ridiculous amount of fuel if it's really +70°.

ULTM8Z

Could be something on the driver side of the engine (on just one cylinder) causing one cylinder to run lean. That's the only side the ECM can "see" since it's the side with the O2 sensor. ECM will react to it by richening the mixture until the lean condition goes away. It could be the condition is so bad that it maxed out the fuel trim range, which will cause the rest of the engine to run "pig rich" since the other cylinders get the unneeded extra fuel whether they want it or not.

Look for a faulty injector, bad spark plug or plug wire, etc on one of the driver side cylinders.

Could also be a faulty O2 sensor or O2 sensor wiring. If the O2 signal wire somehow shorted to ground, it would pull the O2 voltage to 0V, which to the ECM says extremely lean, which would then trigger the same richening reaction from the ECM as in my first example. Maybe the wire touched the exhaust manifold or something and burned through the insulation... that'd result in the short I'm describing.

You may want to think about investing in a good scanner that can read running data.

burnout88

Most common problems in this situation are.

1. 02 sensor wiring
2. Faulty ECM
3. 02 sensor
4. coolant sensor
5. MAF sensor
6. Fuel injectors

Its usually easy to diagnose with a multimeter and a scan tool what the problem is.