Testing a MAF?
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Senior Member

Joined: Aug 2001
Posts: 814
Likes: 2
From: San Jose, CA, USA
Car: 88 IROC-Z - original owner!
Engine: LB9 with K&Ns, MSD, Foil, Taylor
Transmission: WC T-5
Axle/Gears: BW 9-bolt, 3.45 posi
Testing a MAF?
Is there any way to test a MAF without actually putting it on a car and seeing if the ecu throws codes?
Joined: Mar 2017
Posts: 4,255
Likes: 427
From: Portland, OR
Car: 86 Imponte Ruiner 450GT, 91 Formula
Engine: 350 Vortec, FIRST TPI, 325 RWHP
Transmission: 700R4 3000 stall.
Axle/Gears: 9 Bolt Torsen 3.70
Re: Testing a MAF?
Sure - stick it in a flow bench, give it power, and check the voltage output against the MAF scaling table in the ECM.
GD
GD
Joined: Mar 2017
Posts: 4,255
Likes: 427
From: Portland, OR
Car: 86 Imponte Ruiner 450GT, 91 Formula
Engine: 350 Vortec, FIRST TPI, 325 RWHP
Transmission: 700R4 3000 stall.
Axle/Gears: 9 Bolt Torsen 3.70
Re: Testing a MAF?
Agreed. In lieu of a flow-controlled air pump, however, a general indication of whether the MAF is outputting anything relatively normal would be to power the "E" terminal with a +12V supply, ground the "A" and "B" terminals (0V), and monitor the 0-5VDC output at the "C" terminal while pumping air through it using a shop vacuum. Varying the distance from the downstream air connection of the MAF to the vacuum cleaner hose should vary the MAF analog signal level. It won't be calibrated, but it will indicate if the MAF is functioning at all. and with some relative variation.
Joined: Mar 2017
Posts: 4,255
Likes: 427
From: Portland, OR
Car: 86 Imponte Ruiner 450GT, 91 Formula
Engine: 350 Vortec, FIRST TPI, 325 RWHP
Transmission: 700R4 3000 stall.
Axle/Gears: 9 Bolt Torsen 3.70
Re: Testing a MAF?
Incidentally, if you DO check it on the car, the general rule of thumb is 1 gram per second per liter of engine displacement. So you want to see *around* 5 grams per second at a standard 750 RPM idle. To check the MAF at WOT you can then do a volumetric efficiency calculation.
GD
GD
Thread Starter
Senior Member

Joined: Aug 2001
Posts: 814
Likes: 2
From: San Jose, CA, USA
Car: 88 IROC-Z - original owner!
Engine: LB9 with K&Ns, MSD, Foil, Taylor
Transmission: WC T-5
Axle/Gears: BW 9-bolt, 3.45 posi
Re: Testing a MAF?
Tanks, guys!
I have two MAFs plus the one on the car. I'd like to see if the ones in boxes still work or if I should just toss them. One is a Bosch.
I have two MAFs plus the one on the car. I'd like to see if the ones in boxes still work or if I should just toss them. One is a Bosch.
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Thread Starter
Senior Member

Joined: Aug 2001
Posts: 814
Likes: 2
From: San Jose, CA, USA
Car: 88 IROC-Z - original owner!
Engine: LB9 with K&Ns, MSD, Foil, Taylor
Transmission: WC T-5
Axle/Gears: BW 9-bolt, 3.45 posi
Re: Testing a MAF?
I guess I'm trying to see if the wire is broken. Maybe if I could apply power to the burnoff and look inside to see if the wire is glowing. If the fine wire is broken, obviously there would be no glow. If there is glow, the wire is intact. You think this is possible? if so then I could proceed to try to power it and read the signal voltage using a shop vac to get some airflow.I
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