MAF Diagnostics

[Gonzo]

http://www.gonzostoolbox.com/KnowledgeFolder/MAF-Diagnostics.html

 

Just finished this article

It's an easy simple test for a faulty MAF

 

So simple I usually start with this test even before I pull out the scopes or scanners.

 

 

[Tires Too]

Gonzo,

We usually grab the scanner and look at the PID for the MAF. I'll have to try this next time we have a fuel trim problem.

Russ

[Gonzo]

The only "trick" to this testing method is the hard slam of the pedal. You really have to bury the pedal to the floor ... not sorta kinda.. but one time from idle to full throttle. Down and let off. that's all it takes. Be sure loads are off and engine is warmed uo all the way.

[Joe Marconi]

Thanks for the tip Gonzo, I will be sure to share this with my techs.

[Steve Smith]

MAF - VE(volumetric efficiency)calculator. Look it up online or IATN website. Make sure and do it right with correct info entered(humidity, elevation, metric measurement of MAF grams per second from your road test recorded scan data, ect).

 

Faulty MAF clue; p0171 bank 1 too lean AND p0174 bank 2 too lean codes together on a v6 or v8 engine, especially off idle(no manifold vacuum leaks). P0171 only on a 4 cylinder. Verify no vacuum leaks, fuel pressure/volume, O2 response. Verify faulty MAF with VE test.

Edited September 17, 2015 by Steve Smith