Car just broke down on the way home, check engine light came on and the engine slowly died. It would restart but the revs would drop until the engine cut out.

Unplugged the MAF and the car ran although very badly, but enough to get me home.

Is the MAF buggered? or something more sinister?


any help is much appreciated!

EDIT: car is a 1994 Mreg WRX saloon

 

need to do a fault code check but as you have unplugged the MAF it will fault this aswell when it might not be faulty, search for fault code check and instructions will be revealed

 

Don't just do a fault code check as this will definitely show up a MAF fault if it has been unplugged - reset the ecu to clear the existing codes, and then check the fault codes at reset.

 

correct me if i am wrong but if the car runs without the MAF plugged in it means the ECU has learnt to cope without it meaning it is fooked

 

The car does not tickover with the MAF plugged in, it coughs, splutters and dies.

With the MAF disconnected the car runs, although badly.

This would suggest to me that the MAF is foobared as the car can manage without it, but with it in place it cannot run.

Would i be right in thinking this?

 

had the same problem running an induction kit. unplugging the maf will put the car into a 'get home safe' mode and illuminate the check light, with v low boost, new maf and i was back to normal. 95 wrx import.

 

I would say it's definatly a MAF reading related problem - yes. When you unplug the MAF, the ECU uses the throttle signal to determine engine load (and hence fuel & ignition settings). Hence why the engine will run but badly (using throttle to determine load on a turbo car is less than ideal)

However, with the MAF plugged in - as long as the reading the ECU is getting from the MAF looks sensible, it will use this to determine engine load. Which if something is wrong (faulty MAF, air leak etc) would cause the wrong fuel & ignition settings - hence engine dies.

This happened to me on my WRX a while back - turned out to be the MAF. But now I have an ECU that doesn't need the MAF, as I was told they are a bit of a known problem on Scoobys !!

 

The earlier cars don't suffer with the well known scoob MAF problems, these are normally the MY99 cars, although they can still fail and the problems you are seeing definately sound MAF related, i know this through experience!

Where are you located? We have been successfull in fixing a few of these older MAF's, i could have a look for you.