Question on AFM adjustment

[86 shark]

My 86 635NA ,99000 miles, is running rich and failing smog by a factor of 10.
I have done the usual and narrowed it down to the AFM.
I know about disconnecting the O2 sensor and tuning the AFM so it jumps from .2V to .8 V.
What about 2500 RPM where the smog place is measuring?
Can this method be used at 2500 RPM?

Thanks

[tschultz]

My 86 635NA ,99000 miles, is running rich and failing smog by a factor of 10.
I have done the usual and narrowed it down to the AFM.
I know about disconnecting the O2 sensor and tuning the AFM so it jumps from .2V to .8 V.
What about 2500 RPM where the smog place is measuring?
Can this method be used at 2500 RPM?

Thanks

Has your afm been adjusted? You can adjust the wheel inside for tightness to make it run more rich or looser to run more lean... Turbo guys do this to adjust their fueling...

[Jim Con]

Tom,
Howdy neighbor, I'm in Aurora.

I am currently using a friends identical AFM that is from the same car 86 635.

Still am too running too rich to even start.

May have to start another thread on wet black plugs.

[RSheiman]

Well, make sure you have the right/functional fuel pressure regulator, make sure your cold start valve ie the 7th fuel injector, is not stuck open.

I'm not sure where the coolant temp sensor enters the picture here but for 20 bucks, I would swap that out if original.

[Jim Con]

Well, make sure you have the right/functional fuel pressure regulator, make sure your cold start valve ie the 7th fuel injector, is not stuck open.

I'm not sure where the coolant temp sensor enters the picture here but for 20 bucks, I would swap that out if original.

Have tried 2 CTS's , no change, both Ohm out the same.
Have clamped off cold start valve at inlet and fuel rail, no change.
Have correct 3bar FPR, may be the right answer, have not changed that but may.

Now it won't start, pull plugs, dry them out, crank 5 times, no start, pull plugs all 6 wet and black.

Have changed all 6 injectors for newly rebuilt and flowed, no change.

Doesn't this sound like a FPR problem ??

[tschultz]

Have tried 2 CTS's , no change, both Ohm out the same.
Have clamped off cold start valve at inlet and fuel rail, no change.
Have correct 3bar FPR, may be the right answer, have not changed that but may.

Now it won't start, pull plugs, dry them out, crank 5 times, no start, pull plugs all 6 wet and black.

Have changed all 6 injectors for newly rebuilt and flowed, no change.

Doesn't this sound like a FPR problem ??

2.5 change to 3 bar fpr wouldn't cause any drivability changes in my experience. If the vacuum line is wet with/leaking fuel you know the FPR needs to be replaced.

I've talked to a few people with this issue and I had it myself where it was the ECU causing the engine to run too rich.

Can you switch in your friends ECU and see what happens? It sounds like you have explored plenty of options already... and that makes a lot of sense with a similar issue I have had. Especially with the no start condition.