MAF Question/Voltage
Thread Starter
Racer
Joined: Nov 2002
Posts: 366
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From: Sproat Lake
MAF Question/Voltage
I hooked up the "bad" MAF that we took out of a 90S4 only 70K km's on the test bench.
I ran a couple of burn off cycles with it and it now is responsive to flow and seems to work fine but.... the zero flow voltage is a little low - 1.55 volts v.s. 1.67ish for a known good unit. Manual states it should be ~ 1.6 volts
The adjustment screw is available (Japan unit) and when turned doesn't seem to change a thing.
The adjuster screw on the other MAF (North America) we have is plugged/not available.
Paul Jager
www.jageng.com
I ran a couple of burn off cycles with it and it now is responsive to flow and seems to work fine but.... the zero flow voltage is a little low - 1.55 volts v.s. 1.67ish for a known good unit. Manual states it should be ~ 1.6 volts
The adjustment screw is available (Japan unit) and when turned doesn't seem to change a thing.
The adjuster screw on the other MAF (North America) we have is plugged/not available.
Paul Jager
www.jageng.com
Rennlist Member
Joined: Oct 2004
Posts: 10,717
Likes: 58
From: Southern Alberta, Canada
Paul.................check out John Speakes web site for all pertinent info re. MAFs.
I do believe the adjuster screw is plugged at the factory after a specific model year they're non adjustable
I do believe the adjuster screw is plugged at the factory after a specific model year they're non adjustable
Thread Starter
Racer
Joined: Nov 2002
Posts: 366
Likes: 0
From: Sproat Lake
The allen head driven arm is tied to an adjustable pot on the circuit board. It did nothing for the base voltage, but a bit hard to check for the voltage at flow. I suppose I could hook up the central vac to it.
Three Wheelin'
Joined: Jan 2004
Posts: 1,611
Likes: 13
From: Mosier, Oregon
Originally Posted by Shark_gts
The allen head driven arm is tied to an adjustable pot on the circuit board. It did nothing for the base voltage, but a bit hard to check for the voltage at flow. I suppose I could hook up the central vac to it.
Rennlist Member
Joined: Feb 2002
Posts: 7,059
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From: Cambridge England
Hi Paul,
The zero flow figure is only a very crude check that the MAF is working at all. It is not an accurate measure of whether the MAF is any way near calibration.
You are looking for errors of less trhan 1% at known airflow rates across the MAF operating range to be able to determine whether it is "good" or not The no airflow figure is useless for that purpose.
Louis has given you the answer on the pot. You can't adjust the pot to bring a bad MAF into calibration. The pot can help the LH to compensate for an aged MAF, but the adjustment is only useful at idle. This applies only to pre 87 non-cat cars, running open loop.
Regards
The zero flow figure is only a very crude check that the MAF is working at all. It is not an accurate measure of whether the MAF is any way near calibration.
You are looking for errors of less trhan 1% at known airflow rates across the MAF operating range to be able to determine whether it is "good" or not The no airflow figure is useless for that purpose.
Louis has given you the answer on the pot. You can't adjust the pot to bring a bad MAF into calibration. The pot can help the LH to compensate for an aged MAF, but the adjustment is only useful at idle. This applies only to pre 87 non-cat cars, running open loop.
Regards