Simultaneous 181,189 errors

[Larry Bialecki]

Following VSS replacement (Y Pipe removable and reinstallation) I get occasional 181
and 189 error codes. Both errors show up at the same time. I have replaced both O2
sensors, checked for vacuum leaks into the throttle body and in the vacuum system,
replaced the fuel pump, and check my Y Pipe exhaust connections. I have not changed
my MAF sensor. The car runs OK otherwise with no other errors. It appears the errors
occur when I accelerate or decelerate manually. Never during cruise control operation
regardless of the hills I encounter. Any ideas on my problem?

 

[luigisho]

Try cleaning your MAF sensor. It is uncommon for both O2's to fail at the exact same time.

 

[sdpatt]

You likely have a truly lean condition that could be caused by a vacuum leak or bad sensor input. Did you remove any vacuum hoses from the intake? The cruise control is vacuum operated, so check it also for vacuum integrity. Check for hoses that may have been affected during the VSS replacement. The Y-pipe and its connection to teh exhaust manifolds should have no effect on the mixture since the only leakage would be out of the system. You didn't say the year or engine type of your car. If you have a EGR line, you need to check that path too for the inlet of unmetered air. You are looking for air that is getting into the intake manifold downstream of the MAF sensor. The MAF sensor could be cleaned (remove electronics from sensor body and gently spray solvent on the filaments.

 

[Larry Bialecki]

Scott:

Year of the car is 93 with about 160K on it. I did check the MAF sensor and it looks clean but I did not spray any solvent on it. Would carb cleaner be OK? With a 93 do I have an EGR line? I will look for air entering there. The lean condition seams to happen, when it happens, when I depress the throttle for just average acceleration (not mash on it).

By the way, I still have the ATX 2-3 down shift problem. I avoid the problem by manual down shift to 2 when below 20 mph and I expect to accelerate out of a turn or up a hill. I will probably have the trans rebuilt when I have caught up with money. Monitoring the shifting solenoids is really interesting and does help me avoid the problem.

 

[shojuan]

All ATX SHOs have EGR and (with a few mysterious exceptions) all CA SHOs (MTX) have EGR.

Rick

 

[shojuan]

A good injector cleaning might be beneficial. When the injectors aren't flowing 100% a lean condition can pop up because O2 sensor feedback can only do so much to correct A/F ratio.

Rick