Pete; surely a man of your means isnt going to struggle to replace an £80 part? The MAF on this year car is a known weak point; its not uncommon for it to fail on standard cars; oiled aif filters and induction kit nonsense just accelerate its decline rather than being solely responsible for it. As John says; would you risk losing your engine for the sake of saving under £100?

Regards

Simon

Of course I wouldn't struggle to fund a new MAF ............ is it a simple job to swap?

Is there any warranty benefit in allowing a Subaru Main Dealer to fit it?

I am sure that for every MAF sensor to have failed on a MY99/MY00, 30 have been fine - and, of those that failed maybe 75% failed due to aftermarket mods - would that be about right?

Pete

Well I'm going to change my MAF, MY00 coming up for 60k. Something doesn't feel quite right at the moment. I tried the unplug the MAF trick (it's supposed to stall if you do this) it nearly cut out and then sprung back to life so I suspect it's on its last legs.

Standard airfilter / induction BTW.

I cant answer that Pete; Im sure that John can; I assume that its a hot film rather than a wire-type meter but I havent had to do it on my own car, which is an earlier model. Id imagine that if you need to ask youd be better getting your dealer or an approved specialist to fit it.

Even if we had the figures; would you still gamble? After all, you have no way of knowing which group youre in even if you know the numbers; get your cheque book off Matron and sort it out...

easy to change with the right tools. (think it's just a torx bolt in the housing. You need to snap the small nib off or adapt the tool to undo the bolts)

MAF failure has been known to be the main point of engine failure on standard UK turbo engines as well as modified ones of the year. I don't know the proportion but the chance of deterioration is still there so as said for the cost and peace of mind it's well worth doing.

If you no wish to troll the modded line i'll leave you to it ;)

Surely your Main Dealer will tell you for less than £20 whether its going or not??

And could you explain the MAF trick?

Pete

there is no test the dealer can do thats worth relying on, MAF failures dont trigger an error code.

The MAF is easy to swap over, they are held in with torx bolts but you can just use a pair of mole grips to start them off then they spin out by finger, if you dont have the correct torx bit. It's a 10 minute job.

The reason you shouldnt use a reground crank on an STi is due to the high rpm they will see, regrinding doesnt give good results.

This is an interesting read from Australia:-

"Subaru vs. Aftermarket Filters
Guys, you may already be aware of this - but I will tell you anyway. A friend of mine who works as Supervisor in a Subaru dealership has received an emergency bulletin from Subaru Australia in relation to non-OEM air filters. It seems that the oil from the air filters is destroying the airflow wire in the meter. Subaru Australia is NOT covering warranty claims for these meters. I am now personally not happy because I have a K&N filter pad in the original airbox on my Subaru and now have to replace it with an OEM filter at something like $38 a pop"

Pete

That's extremely well-known, Pete. :)

My 02 WRX is on 85k, is it a good idea to change the MAF as a precaution or are the bug eyed WRX's less prone to the problem? I have had one engine go so don't want another. Slightly worried as the ECU gets reset a few times due to the de-cat.

Mike

its the MY99/00 that has the easily contaminated MAF mike.

Thats ancient news Pete.

As John said most of the main dealers don't know how to check for a failing MAF unless it's actually giving a fault code. By that stage you may have already caused some damage.

The theory behind the diagnosis I defined is that the engine managment learns around an under reading MAF to such a point that the signal from it at idle is so under it's ignored. So unplugging it would result in no change to the running of the engine. If it was reading correctly then the engine should stall. However this is not a hard and fast way to check it out, if it doesn't stall then replace the MAF, if it does stall then the MAF MAY be okay. Another way the check is an ECU reset, disconnect the battery for a few hours, reconnect and start up. If the idle is all over the show then replace the MAF.

Of course preventative measures can be taken, a KnockLink is a good idea to give an early warning of any detonation, a LambdaLink is also useful as you can check the fuelling is nice and rich when on boost.