XXGOMXX

What happens?

will a knocklink show me>?

TonyFlow

A hot-wire MAF works by basically having a hot-wire (duh), which air flow will try to cool down. the amount the wire is cooled is converted into a voltage which will tell the ECU how much air is going into the intake. If this voltage under-reads (i do not think a faulty MAF will ever over-read), the ECU thinks there is less air than there is, and so reduces the amount of fuel going into the combustion chamber - hence the mixture is leaned out, creating higher temperatures and in severe cases a big BANG!

The_Judge

...ditto, plus a knocklink will show you if you're detting, which could be as a result of a failing MAF, but not limited to.

dij

Im interested in this subject also.

May have an obvious answer to this:will the hot wire break if its shocked or dropped?

Does oil contamination cause the main failure to MAFs?

Can it be cleaned?how and with what product?Brake cleaner?

Is the replacement part from Subaru an updated or more reliable part?

I seem to remember 1 pin less on the connection on the new part.Is that correct?why?

Does the older model ( v1,2,and 3) have a hot wire type maf?
Are they more reliable?

Sorry to be a pain
am I being a pain?(ok dont answer that one)

The_Judge

Apparently shock doesn't do them any good.

I think the majority that fail are down to some sort of oil/dirt contamination.

Yes, but because of the fragility of it, you could potentially completely **** it.

Apparently, but the one I got back in July looked identical to the one I took out (MY00).

Pass.

Pass (again ).

I think so. The MAFs that seem to be causing the most trouble are the MY99/00s.

That's quite alright.

Yep.

Too late...

dij

Thanks for that.

Ill think up some more questions later and try and pick your brain again,if you can stand the pain.

TonyFlow

Think the earlier ones were a film syle MAF.

The newer MAF does indeed have 1 less pin (dont ask me why though!)

dij

Is it fair to say that the MAF is a design flaw?

What are the common symptoms of a faulty MUFF?

zhastaph

Stacks of cars use a MAF to meter air going into the engine and generally there are no problems. The MAF in the MY99/00 seem fragile though for obvious reasons Subaru would never admit to this.

The big problem with turbo charged cars is that they are prone to serious detonation, running a lean mixture (cos of an under reading MAF) is just a recipe to disaster.

**** off big 'ole in one of your pistons And unfortunately this is the first many people know about it.


There are 2 types of MAF failure;

Complete failure. This will normally be picked up by the ECU which will throw up a CEL and then run in limp mode.

Gradually underreading. This is normally casued by oil contamination across the element. And unfortunately just seems to happen to the MAF in the MY99/00. If your lucky you'll have a knock link and be warned by the ever increasing activity or even an AFR which will show a gradually leaning out mixture.

Some people report a hunting idle, but I don't think this is common.

The_Judge

Obviously, this depends on the condition, but these are common symptoms to look out for:-

- Itching & burning.

- Soreness, swelling and pain.

- Discharge.

I'm no doctor though, so if you're concerned about something specific, visit your GP...

little_idiot

LOL
Discharge is one of those words that conjours up all sorts of nasty skanky images

Graz

I'm hoping a knocklink as well as a lambda link (AFR meter) will alert me to any problems with mine. The Knocklink to see if there is any det (=bad) so that I can stay off boost until what ever is causing it is fixed. The lambda link should confirm a nice rich mixture at full boost / wide open throttle conditions. If is isn't rich either the MAF is under reading or the lambda sensor is knackered, either is bad!

Hoping to fit this lot and a boost guage in the next few weeks

dij

LOL

That was the 'real' critical question.

Screw everything about the MAF.......then again you could just screw a MUFF..

dij

I had similar symptoms that whent away after the MAF was replaced.

Can the hunting problem be linked to a faulty/misreading lambda sensor?

zhastaph

Yeah, I had this exact problem on my STi5, cured by replacing my Lambda. Only occured after the car had been 'razzed' or motorway'd though.

SCOOBYD00

That made my morning complete.

LOL

The_Judge

SCOOBYD00

Judge still laughin at that one... however...

Is it possible to simply clean the muff... after noticing the increasing risk with the Knocklink? - I assume it is very delicate.. ?

Sorry - difficult to ask a question with muff on my mind..

The_Judge

I believe Zhastaph posted that, not I...!

If the muff had been cleaned and maintained properly in the first place, these symptoms probably wouldn't have developed.

Muffs are delicate, yes, so scrubbing it with a scourer's gonna hurt like hell... better to use a sponge, gently...

Franko

Lol @judge

And when its making your engine run lean it gona build up heat and thats bound to end up with piston failure

SCOOBYD00

Deep heat then?

Sorry close to lunch....

The_Judge

Talking this level of bollokcs before the pub... oh dear.

SCOOBYD00

Wire brush & detol....

It's the weekend whoo-hoo!

The_Judge

Indeed. And the start of the F1 season. Quality...

SCOOBYD00

Last year at Silverstone I thought my ears were going to bleed!!

A note to all those you think a full decat is loud lol