My deadstock factory standard 86 951 is running rich when idling. In the mornings when it is cold, it's fine for some time, until it warms up.

It's not a problem under accellaration or on the open highway, since it's able to burn the excess fuel. It's not running rich under boost. Only when idling, so much so that there is some black smoke coming out of the exhaust while idling. It's like I had left the choke on! Otherwise the car is performing well.

As I'm a newbie to this, please explain with detail your responses if at all possible. Many are using abbreviations on this forum, that don't make much sense to me!

 

No takers?

Any advise REALLY appreciated!

 

The first thing would be to do some mantenace, like filters, check your plugs, and more impportanly your O2 sensor. If it check fine the I would look very closely at the AFM or coolant temp sensor.

Do you have a way to get the correct values to check this items?......Let me know if you need them and good lock!. let me know how it went.

Regards,
AL

 

Hi AL951

Thanks for the response.

I've changed all filters, the plugs are new, I had the AFM recoed and the engine temp sensor seems to be working (the engine stumbles when I disconnect it).

How do I check the O2 sensor? (pardon my ignorance)

Cheers

 

no problem!

It look like you cover the basics.Now keep in mind that recoditioning your sensor doesn't mean it is working ok.Let me ask you a question, Since when have your experience this problem?

Regards,
AL

 

To check the sensor you are going to need a DVM, that has a scale of less the 2 volts. The range you ar going to see is between .2-.8 volts and it should switch back and fore.

Their are three wires coming from the sensor, their usally two with the same color, this is for the O2 heater, the third one is the signal. with the sensor connected , strip this thrid wire and put your + lead their with the engine running at idle ( warm). the - lead you can put on any ground.

If it is peg to high or to low, ( usually a contineuos low reading like .1 or .2 will cause a rich conditionand a high reading like .8 or .9 will cause a lean condition) try to disconnected and see what happens. if it smooths out then the sensor needs replacement.

Some other things to check would be your fuel pressure and last your injectors. again if you have further question shoot me a PM.

regards,
AL

 

Thanks for that. I've had the problem since I bought the car (I've only had it a few weeks). I recoed the AFM straight away, which has made it better, but not 100 %.

I'll have the O2 sensor checked out and will go from there.

Once again, thanks for the info!

Cheers

 

fuel pressure?