rroberrto

hi,

Car's a MY00 with hot-film type of MAF sensor, which had been acting weird in the last couple of days, mainly presenting as hunting idle at both cold and hot, but will be gone once the accelerator is depressed no matter at light cruise or WOT.

I've checked all the connecting hoses which seemed to be fine. Although the check engine light remained off at all time, i thought MAF might be the culprit since once i had it disconnected, the car goes into limp mode but idle stayed almost rock solid.

So, here's the question. Can I clean a hot-film type MAF? and How?
I mean i took it apart once to have a peek inside. But i'm not sure where in the apparatus is the sensor itself located? And what should i use to clean it? compressed air? aerosol solvent spray for electronic contacts? Can anyone help?

thanks and merry X'mas everybody,
robert

HHxx

RRoberrto,
I don't think you can clean the hot film type, if this is faulty then the film has burnt away. I have heard that you can clean the hot wire one as it just gets dirty.

The MAF sits in a tube right next to the airbox. Thats if you still have the airbox, else it would be bolted directly to the cone filter.

Try and find someone willing to lend you a MAF unit to test.

All the best for Christmas and I hope you sort your problem out.

H

dmel

Rroberto,
I had exaxtly the same symptoms as you, and at Subaru they informed me that my MAF needed changing (hot-film, MY99); no check engine light yet, no diagnostic codes present.

Since I was going to change the thing anyway I thought why not give it a try and clean it with pure alcohol. I was extremely careful, not touching it, letting it dry on its own as they suggest on the TDi and I-club forums.

That was it. I completely FU**ED my MAF. Next thing in the morning check engine came on, the engine would not rev above 4000rpm, it had an extremely abrupt response.

Merry Christmas to all.

Dukas

It can be cleaned but it's not an easy task.
First take the sensor out of it's plastic cylinder. You'll need a special screwdriver for that (called T-Cup in Hebrew not sure about the English term).
Gently clean the sensor using compressed air and aerosol spray for electronic contacts. Oil remover spray can also help.

Help I manage to help and save money.
Merry Xmas from Tel Aviv.

rroberrto

hi,

thank you guys for all your comments There is a Santa and let me tell you why! First his evil twin was here, since my car's idle was a wreck and getting worse all the time. And when i tried to get some help from this BBS my only computer at home, a laptop with an ancient pentium 166 MMX (i'll bet not much people here remember what it stands for )went kaput, and left me stranded with no internet conection for more than 2 days.

so, in a moment of desperation a man can get irrational, and i jsut went out and took the MAF out of the car, 'cos i thought even if i f**ked it there's really nothing much to lose? And guess what? under the penetrating beams of maglite i finally saw the sensor itself embedded in a plastic post, that is looking thru the mesh. It was almost completely covered by a thick layer of oil and dust, now that almost confirms my previous suspicion of MAF being the culprit for the idle issue. The only question remains, how do i clean it? It would be ideal if i can take it out of the casing but i dont have the tool nor the patience. So i just sprayed some kind of electronic contacts cleaner across the mesh on it (alcohol based) then blowed it with another can of compressed air. After several passes it looked now clean and shiny. I put it back on on Christmas night, really hoping for the miracle to happen.

And voila! I started the engine, no check-engine light, and the idle is now stable like it should and used to be. I just saved myself a trip to the delaer and 200 squids! And things get better since i got myself a new laptop with pentium III 1Ghz with 256MB of memory and a scintillating 14.1 TFT screen.

That there's no Santa beyond a kid's wildest dream? gimme a break!

merry Robert

mutant_matt

rroberrto,

Glad you hear you fixed it - well done, not many others have managed this on a MY99>=....

BTW, MultiMedia eXtensions

Matt