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Agree, Offtrack. I have done pressure drop tests on other cars and on high demand you will always have some resistance that causes pressure drop in the inlet circuit, but usually not the aircleaner element, usually the trunking .
Some cars have up to 30 inches of water drop or about .07 bar. seeing the bars are 975 that is a drop of .025 which suggests about 11inches of water which is quite good.
Regards Philip A
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.Quote:
Originally Posted by PhilipA
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
Quote:
Originally Posted by OffTrack
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
The Td5 MAF is part of the 'engine load' array of sensors, a 'driver demand' type of input for the trans ECU to aid in correct change points. The V8 D2 is even more effected by a faulty MAF in this department. The Thor engine management (Motronic as you know) coupled to the autobox allows for TC lock at speeds as low as 45km/h on a trailing throttle or light load cruise. When a MAF is faulty in these they usually become incredibly gutless and impossible to drive without misfiring from cold, or to a lesser extent the trans misbehaves quite obviously with erratic and early or late shifts etc.Quote:
Originally Posted by PhilipA
JC