dn12345

Further to my problems (misfiring sensation/popping under boost), just tried disconnecting the MAF sensor and the car stalled. Apparently this indicates that the MAF sensor is ok. Is this correct?

Have also ordered 4 new coil packs. Can anyone out there re-assure me that this was the correct diagnosis?

Thanks

Dave

James Neill

iTrader: (1)

Apparently so. If the car stays running then that indicates the MAF is faulty.

TonyFlow

Hmmm, not quite, If it carried on running, then the MAF is definitely fubar. Unfortunately, the fact it continued to run does not prove a thing, you would need to get the voltage output of the MAF to prove it's state.

dn12345

The car stopped running when it was disconnected. How would one go about getting the voltage output?

Thanks in advance!

James Neill

iTrader: (1)

But he said it did stall though (ie, didn't continue to run)

TonyFlow

A Maf isnt a unit that fails by suddenly stopping working, it degrades over time, and the ECU manages to cope with it (meaning a lot of people have no idea it isnt working properly), this then means that the ECU is adding fuel for a fixed amount of (metered) air, but this metered amount is not correct leading to lean running, and possible engine failure. The reason the test above kinda works is that the ECU has compensated to a point that the voltage from the MAF is not needed to keep the car running (as the voltage has decreased on a sliding scale, the compensation has increased), obviously, the ECU may not be quite at a point that it can compensate entirely for no voltage.

You would need to put a multimeter into the signal wire from the MAF and then reference the output of that with what a correctly functioning one would see (not sure what this should be, but a search on here or 22b.com should bring back the required results).

dn12345

Thanks alot guys, will have a look around and see what comes up. In the meantimne guess i'll go easy on the driving - wouldn't want to break the engine!

V4JDMSTi

iTrader: (2)

would the diy fault code check not work? that way it'll tell you what's wrong with it by a series of flashes from the cel light?

TonyFlow

If it is MAF related, it doesnt always chuck a CEL for the above reasons.