P101 Error Code (Mass Air Flow)

[DanG144]

Randy,
Thanks for catching that.
Dan

[ScotR]

Cam and lifters are worn out.

[JASONP]

Originally Posted by DanG144

We stay low tech, but I am always willing to learn a better method.

This is all going from memory...

I do the basic settings block 3 test with VCDS. Normally when the EGR is open you get half the flow with the EGR closed. Say 450 and 225 mg/stroke. If the flow dies off to 120 or so when the egr is throttled open, that is a sign of either an EGR problem or plugged exhaust, causing high backpressure, causing low fresh air intake flow.

You can also do the OUTPUT TESTS, one of them checks EGR function as well, but at idle instead of at 1400 rpm as the BASIC SETTINGS test does.

I also take a log of full throttle operation from 2k to 4k in 3rd, and see if air flow dies off excessively at higher rpm. This can be a problem to judge unless you have a log of the same car/tune during the same run. So then...

Just remove the three bolts from the turbo to the downpipe, tie it back, and go for a short full power run just like before. Compare this to logs from before, and see if air flow is up for a given intake pressure and RPM.

Dan I do think you are spot on here car idles bad, owner says he gets crap milage,the EGR Duty Cycle looks (to me ) way too high for idle, the number of MAFs he's replaced in the past few months, and he says he gets tons of balck smoke.

Ben the easiest way I can think of is takke the car to a muffler shop and have them remove the CAT for inspection, OR you can go to a Commercial Diesel Inspection shop and have them do an exhaust analasys.

We can also try turning down the IQ with VAG.

[DanG144]

I would inspect the cam, as I said in post #6.

I don't think you can adjust fueling on a BRM with VCDS.

[dropdeadsheds]

Pull egr out and check to see if the valve in the egr is open. Like a car valve it should be seated closed. If you can see light though the seat of the egr vavle thats it. Thats the causes of the black smoke. 3 bolts to pull and wiggle it out on a brm motor. Please check first. I just did one on my 2005.5 jetta brm. David