Run Rich

[Derek]

Hello from down under,

My 89 C4 L98 has developed a problem,
After running normaly for 10 mins hot or cold,the engine suddenly runs very rich with soot coming from the exhaust .
I disconnect the battery for a few moments and start again ...all normal ,then after a short time RICH,with the `service engine soon` light coming on.

dont have a code reader at this time to read any codes

look forward to any ideas

:eyerole ..Derek

 

[gmjunkie]

Hard to say without a Code,But there is a good chance it's the Temp sending unit not telling the ECM that the engine is warmed up!!(I've had to change several) I believe there are 2 on the 89,the one you will be looking for will be around the thermostat housing!! Could also be a Oxy sensor,you really need to check codes!!

Hello from down under,

My 89 C4 L98 has developed a problem,
After running normaly for 10 mins hot or cold,the engine suddenly runs very rich with soot coming from the exhaust .
I disconnect the battery for a few moments and start again ...all normal ,then after a short time RICH,with the `service engine soon` light coming on.

dont have a code reader at this time to read any codes

look forward to any ideas

:eyerole ..Derek

 

[gmboileau]

Hi
Since the check engine light is coming on it's giving you a hint as to the problem. You can get the codes without a code reader by (with the key off )installing a jumper wire on the ALDL connector between pins A and B. When you turn the key to the run position the Service engine light will flash the stored codes. A code 15 would verify the temp sensor as mentioned in a previous post. Without the codes however you can replace a lot parts without fixing the problem.

Cheers
Gary

 

[Derek]

Hello again.
Thanks guys for the info,I ran the car for hour ..can you figure ,it wouldnt fault??ad
runs ok for now.
But when it does I`ll be ready to read any codes it may throw.In the mean time I will check for loose connectors on the thermal and O2 sensors.
thanks again,this forum is a great resource.

 

[MIKEM3401]

Derek,

Just resolved the same issue last month on my 95 C4.
It is definetly the O2 sensor.

MikeM