martyp

Would someone please verify that the MAF testing values on WSM page 24-113 (steps 4 and 5) are correct for my car?

Sometimes I get confused looking through the year variations; the manual is poorly written IMO. I can't find anything newer than that page.

Thanks.

smiffypr

Yes, all the MAFs are the same.

martyp

OK thanks smiffy

John Speake

The tests are fine as far as they go, but only really useful for gross MAF failure. Don't take the resistance values quoted as gospel. Any tolerances are taken out during the calibration process.

martyp

Hmmm. I'm reading pins 3 and 6 at 487.5 K ohms (spec 0-1K), and pins 3 and 5 at 282.3 K ohms (spec 3.6-4.1). Within calibration range, or could this be a contributor to my cold start issue?

John Speake

Your meter seems to be having problems with its autoranging..... as I said, you can't really tell much from those readigs except the airtemp sensor and hot wire are intact.

If the car runs well when warm, then the MAF is most likely OK and the cause of the cold start problem lies elsewhere.

When the engine is cranking, the injector pulse length is fixed by the LH ECU, the MAF has nothing to do with the injector pulse length calculation.

martyp

I rechecked at work with another meter, and got similar results - until I looked closely at the connector on the MAF itself - Doh! I mistook the connector diagram at the top of WSM page 24-113 to represent the MAF side. The diagram represents the wire harness side - I was measuring the wrong pins.

Measuring the correct pins shows both the idle mixture and the heating element values to be within the range specified in the WSM.

Based upon your reasoning it sounds like this is a moot point anyway, so I'll continue looking at other possibilities.

Thanks for your help John. I really need it!