Electrical Fuel System Prolems. Stumped Please Help!!

Unit 5302 · 06-09-2001, 11:37 AM

The ECU or MAF is most likely bad.

The fuel pump relay is getting power KOEO, which it should only get the signal for a brief couple second time frame. You must not have let the injectors inject long, if you had, there should have been enough gas in the cylinder to hydro lock it.

Running poorly when your first start it means you can throw your emissions crap out the window. That gets ignored until the engine reaches operating temp.

There are a few different things that can cause your extreme rich running condition. Even fewer with the car to the floor.

-Mass Airflow Sensor
-Temp Sensor
-Computer also known as ECU, PCM
-Incorrect injector size. Do you have the stock orange 19lb injectors?

If you haven't replaced the injectors, I'd be suspect of the

-MAF
-ECU
I would say the temp sensor would be hard pressed to cause a condition that bad, especially when the engine is cold.

I don't know if the MAF is in the fuel pump relay circuits. I'd certainly be suspect of it more than the computer if it is. Usually the computer will at least work in open loop (wide open throttle).

[This message has been edited by Unit 5302 (edited 06-09-2001).]

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06-09-2001, 11:37 AM	#4
Unit 5302 Registered Member Join Date: May 1999 Posts: 5,246	The ECU or MAF is most likely bad. The fuel pump relay is getting power KOEO, which it should only get the signal for a brief couple second time frame. You must not have let the injectors inject long, if you had, there should have been enough gas in the cylinder to hydro lock it. Running poorly when your first start it means you can throw your emissions crap out the window. That gets ignored until the engine reaches operating temp. There are a few different things that can cause your extreme rich running condition. Even fewer with the car to the floor. -Mass Airflow Sensor -Temp Sensor -Computer also known as ECU, PCM -Incorrect injector size. Do you have the stock orange 19lb injectors? If you haven't replaced the injectors, I'd be suspect of the -MAF -ECU I would say the temp sensor would be hard pressed to cause a condition that bad, especially when the engine is cold. I don't know if the MAF is in the fuel pump relay circuits. I'd certainly be suspect of it more than the computer if it is. Usually the computer will at least work in open loop (wide open throttle). [This message has been edited by Unit 5302 (edited 06-09-2001).]