Thread: First run of new evo-logged Air flow circuit HIGH

OK for what it's worth
1-2 16.6 Kohms
1-3 13.1 Mohm
2-3 13.2 Mohm
I wonder if the 0.2 difference on 1-2 has anything to do with it or just gauge error.
BTW it was backwashed with Jaycar electronic contact cleaner about 4 weeks ago,plus new filter element, plus cleaned inlet temp and pressure, and MAF.

Regards Philip A

Originally Posted by PhilipA

OK for what it's worth
1-2 16.6 Kohms
1-3 13.1 Mohm
2-3 13.2 Mohm
I wonder if the 0.2 difference on 1-2 has anything to do with it or just gauge error.
BTW it was backwashed with Jaycar electronic contact cleaner about 4 weeks ago,plus new filter element, plus cleaned inlet temp and pressure, and MAF.

Regards Philip A

The .1Mohm difference is unlikely to be an issue. The readings are possibly a bit low but as nobbycrlk points out there are significant limitations to using resistance as a guide.

According to RAVE when the engine is running the one of the MAF elements is heated to 200°C above ambient while the other is kept at ambient temperature. The current used to maintain the 200°C difference gives a non-linear signal related to the amount air flowing over the elements. This is converted to a voltage between 0-5V which is then converted from analog signal to a digital representation by the ECU.

The resistance measurements we are getting are of the output of the electronics in the MAF, and reflect the MAF in a state that bears no relationship to it's operating condition. Basically we don't know what we are measuring, so it's difficult to attribute any definite meaning to the readings.

cheers
Paul

So it appears with mine that the sine wave gets so close in duration that the count goes out of range of the ECU.
Interesting that inVW diesels that the MAF only affects injector duration and EGR. In the D2 I understand it also affects gear change timing.
Yet fuel economy is fine on mine so I am looking forward to having one that reads normally and not high.

Regards Philip A

Originally Posted by OffTrack

The AAP on the intake side of the air filter so most of the variability is related to the amount of air being drawn into the turbo. As boost increases the depression cause by the airfilter also increases. When the engine limits you tend to see rapid changes of atmospheric pressure due to the turbo spooling down.

I couldn't see anything in PhilipA's recordings that were suggestive of am AAP sensor problem.

The boost figure are all over the place because the MAP is overreading and the ECU is rolling the airflow figure to 0 resulting in fuelling being cut. I think it's fairly safe to say it a symptom rather than the cause.

cheers
Paul

Thanks for that. Makes perfect sense.
I wasn't sure where the AAP was located

The rolling airflow calculation is interesting. I wonder if this is purposeful software engineering.

The new MAF has FINALLY arrived from UK and I installed it last night.

Gave it a bootful this morning a it revved out cleanly to the change point.
SO SUCCESS!

Interesting that the auto change points have moved upwards in revs a bit on light throttle. The auto really depends on the MAF signal for it's change points.
Regards Philip A