Hi all,

My girlfriend's V6 '91 Firebird is only managing about 20 MPG and the engine stops whenever you pull up to a junction or roundabout (It's an auto box by the way). I was thinking it might be helpful to be able to read the fault codes. How do i go about doing this? Any help much appreciated.

 

This will be one of the only times that a haynes manual will come in handy. Go to the parts store and look up the engine error codes or check engine light section. It tells you which wires to connect to get the engine codes and has a list of codes with tips on how to fix them. First things first, get a 15.00 book from the parts store.

 

Turn the ignition to the "ON" or "RUN" position (engine off). Make a note of the "SERVICE ENGINE SOON" light. Light should come on steady. If there is no light or the light flashes, do not proceed with remainder of test. Results of test will be invalid.
Turn the key on to the "RUN" position (engine off). Ground the diagnostic terminal (ALDL terminal A to B). The "SERVICE ENGINE SOON" ("CHECK ENGINE") light should flash a code 12. This is displayed, on the Check Engine light, by 1 flash followed by a short pause then 2 flashes. This should repeat 3 times. A code 12 should always flash when an on-board diagnostic check is performed. Any other codes, stored in the computer (ECM/PCM), will follow a code 12. If any other codes are stored, or code 12 does not flash, or the CHECK ENGINE light is on steady, or not at all, refer to DIAGNOSING AND TESTING PROCEDURES/DIAGNOSTIC CHARTS.
hope this helps...

 

Thanks, i'll not be able to get near the car till about thursday but i'll let you know how i get on.

 

Just out of curiosity would this all be the same on an 1990 V6 tempest??

My sisters having some problems with her car and ill be down there to see her at the end of the month and would like to be able to figure it out.

 

should be same for all pre obdII gm cars....