A month or two ago I replaced the failing MAF sensor on my 2001 Classic. Since then the car has never really regained its sparkle and has run badly getting steadily worse until this week is was diagnosed with a knackered bottom end, probably a melted piston.

It is booked in for a rebuild in a couple of weeks but I'm finding it difficult to come to terms with the cause. Basically as I see it Subaru have fitted a substandard part that is prone to failure. It turns out that when the MAF fails it often damages the engine to the point, as in my case, that it needs nearly £3K spending on it. This can't be right, can it?

The car was bought as a Subaru approved car 18 months ago and has been serviced on time at approved dealers. Do you think I have any come back on Subaru for the failure. I think probably not but what have I got to loose by trying?

Stephen

 

MAF failure is a very common problem with MY99/00 cars unfortunately.

When on their way out can cause under fueling and potential det/pinking/knock, leading to melted pistons, usually No 3

 

early signs for failing m.a.f.'s? assume mines fine, as it runs smoothly, but be helpful to know what tell tale signs to spot early...

 

I'm afraid it's a known weakness mate. Sounds like the damage was done to your car by the time you got the replacement on as replacing the MAF should mean the car reverts back to rude health. If you drive on boost with a dodgy maf though.....well, you now know what can happen. Did you get any signs that all was well, hesitation on boost, uneven idling, threatening to stall at junctions etc..

Might be worth getting a knocklink on your next engine, if you miss the above signs, it'll tell you if a dodgy maf is making the car run lean.

Who is doing your rebuild?

BTW, IIRC a dodgy maf can also take out the Lambda sensor: double trouble! Might pay to have this checked!

Ns04

 

As soon as the warning signs reared the head, i.e. hesitating etc, I spoke to Steve at Cotcomp, he advised a new MAF, I did this immediately but it seems I was too late. I don't know what more i could have done to prevent this problem. Surely fitting this Knocklink thingy is all well and good but the car is standard and I'm not into filling my car with flashing lights, I'll be buying under car neons and illuminated washer nozzles next!!

Years ago I had a cam belt snap in my 306 GTi 6. The car was on 54K miles and the belt was not due to be changed until 72K. I wrote to Peugeot and successfully proved the cam belt was not fit for purpose and the dealer duly fitted an brand spanking new motor. In my current circumstances surely the MAF is not fit for purpose, QED. You would think Subaru should at least contribute to costs or something.

Stephen

 

My maf was replaced last year - my00 classic.

Symptoms were the feeling that it was misfiring in 4th and 5th on the motorway.

Engine check light came on - got it sorted and now all is ok. Cant help wondering what damage was done - it does make the piston slap noise upon startup from cold - but loads of people say thats normal for a 99/00 car.

Runs fine now MAF has been replaced.

 

what do you mean by misfiring in 4th and 5th? i sometimes get a slight knocking noise when cold, reminds me of what a diesel van sounds like. very faint and as soon as shes warm buggers off...

wonder if thats what happened to the original engine in the car that went at 70k before i owned it. second current engine is on about 57k miles now.

 

Earlier versions were common for piston slap from cold.... my99/00 were not known for having that problem.

 

It's hardly bling mate (in spite of the jokes on here)!! I'm a 30 year old Dr, so neons etc are not to my taste

The point is, if the car is starting to run lean, cause of a dodgy MAF it'll know about it before you will!

They are important for modified cars. However, why might it be a good idea for a std car to have one? Well, your case answers that question.

Good luck getting it sorted.

Ns04

 

i think but not 100% without hearing it, the slight knocking noise when cold is piston slap but i thought it was only the 1997 and 98 uk turbo's that suffered from that, hopefully someone will correct me if i'am wrong.