1998 740il ODB codes

[boomer1]

Need help, Check engine light.

1) Electric thermostat final stage

2) pre cat o2 sensor aging

3) fuel trim QL additive

Looks like 1 and 2 are warnings, but #3 not sure about.

[Jack Dabsy]

Is it running "rich" or even misfiring?
Have a smell at both tail-pipes a get back to us with your results mate!

[boomer1]

No Misfire, no smell it's running rich, No smoke coming out when accelarating.
Car is running smooth even during idle.

[Jack Dabsy]

TBH I would firstly disconnect the battery for an hour to reset any OLD codes...
Reconnect and notice that the car might run a little worse for a while as the ECU Re-Learns your driving techniques/habits lol... And maybe while it's disconnected, why not clean the MAF? This might be causing the richness.
Just an idea my friend !!

[boomer1]

Originally Posted by Dabsy

TBH I would firstly disconnect the battery for an hour to reset any OLD codes...
Reconnect and notice that the car might run a little worse for a while as the ECU Re-Learns your driving techniques/habits lol... And maybe while it's disconnected, why not clean the MAF? This might be causing the richness.
Just an idea my friend !!

I just recently noticed a random puff of smoke sometimes when accellarating from a full stop. Thanks

were is the ECU and MAF location.

[Jack Dabsy]

The ECU is under a plastic cover under the hood behind the suspension strutt.
The MAF's are between the airboxes and throttle-body...

[boomer1]

Thanks. I'll check it out.