RB5_IOM

How much does it cost for the part and where is it best to get it from?

Thanks

richiewong

What MY, most common MAF failures occur on MY99/00
Part No22794AA010 Meter CP-Airflow about £75 from any dealer

RB5_IOM

MY99 RB5

Thanks

pslewis

How do you know its gone?

Pete

Dark Blue Mark

Id just replace it annually regradless...

MB

RB5_IOM

I live in the IOM and don't have a dealer. Where is the best place to order from???

pslewis

Pete

RB5_IOM

ECU in safe mode, won't rev over 3000. poor idle. Spoke to BRD who installed my TEK3 who advised the MAF sensor

ozzy

A Dealer on the mainland probably. BRD would probably sort you out too.

pslewis

Thats good to know ....................... reading some of the threads on here would make you think that the MAF goes and then the Big-Ends go and pistons melt .... in quick order

I'm glad that notice is given .............

Good luck!

Pete

RB5_IOM

Thanks!

I presume the ECU goes into safe mode to save the engine.

TonyFlow

It can do - or the readings can gradually deteriorate, meaning no fault is found, so safe mode is not enabled, meaning engine can run leaner and leaner and leaner!

Usually shows up with idling problems though!

Dark Blue Mark

Agreed with Tony, it very rarely goes into safe mode in my experience,and rarely gives a CEL, hence my reasons for changing them regularly (Pete)

If must be completely dead to go into safe mode?

MB

ozzy

Agree 100%. The ECU has to see a complete failure before it does anything to prevent damage. If the MAF is just giving false readings, then it can just run very lean and it's then when you start melting pistons.

It's not just a Subaru trait. My Dad's Vectra needed a new MAF and it was twice the price of the Impreza one.

Stefan

RB5_IOM

Thanks for the advice. Contacting BRD now

Sub69

I had no indication that mine had gone other than a slight knocking at idle now and again.

ozzy

idle was fine on my car. indication was a lumpyness and hesitation when accelerating.

RB5_IOM

Certainly a common thing then. Will hopefully have a MAF on order today

Dark Blue Mark

Sub69 - damaged MAF wont cause knocking on idle.

MB

pslewis

Theres a whiff of an Urban Myth here isn't there?

Pete

Dark Blue Mark

Nope. Why? MY99/00 MAF's are known to fail with little notification. As they inform the ECU of the assumed engine load, a failing one can be extremely dangerous on boost. Lack of required fuel causes heat build up in the combustion chambers, and therefore pre detonation of the fuel, thus damaging pistons. I could go into more detail but its been covered over and over.

Its well proven that they've caused engine failures. A suspicion I agree with is that its the reason for the tweak in the ECU map between 99 and 00 cars. Looks like Subaru had a number of failures and tried to cure it by making the later map more "safe" Not sure whether they were oblivious to the MAF or tried to mask it with a conservative map.

Hence why AE801 ECU's are more sought after (more power!)

MB

ozzy

Are you talking about yourself here Pete

A failed MAF will result in Limp Home Mode.

A failing MAF may cause engine damage. Since there's no real method of measuring the fault on the MAF, the amount of damage is unknown and may simply look like good or bad luck.

It's no myth, but since the measurement and diagnostics can be vague it just appears like pot-luck. There are well-known symptoms that may suggest the MAF. There's nothing written in stone until the sensor fails completely and results in a CEL. The chances of that are pretty slim, so you need to watch out for the symptoms and use your common sense.

My car's had 1 replacement MAF in almost 6 years. It's also had 1 Lamda sensor (2.5yrs ago). Since my car lasted 5 years on it's first MAF, I'd need to be convinced that it needs a new one every year on a regular basis.

Guess it would all depend on how many miles you drive. Since the majority of mine are motorway, perhaps I would get 3 years out these sensors and not have too worry as much.

Stefan

Dark Blue Mark

Worry is the symptoms are masked by the learning of the ECU.

Unless you have an AFR fitted, and can monitor the MAF behaviour, I would change it out regularly, but thats just me - im an overcautious engineer

MB

Mr Pants!

My, MY03 STi, is having its MAF replaced on Friday.

The Symptoms were a bit of hesitation around 4000rpm under hard acceleration and that was it.

So hopefully when the new one is installed my car will feel nicer!

RB5_IOM

ozzy

I have had MY00 RB5 for two years and never changed the MAF. I had a new Lamda last June when the TEK3 was installed. I have now ordered a replacement MAF sensor from Power Engineering. Fingers crossed, this will solve the problem.

Peanuts

iTrader: (15)

friend of mine had stalling issues, car would cut out when coming to a stop at junctions etc.
when fully warmed it would just catch it, but then hunt for a stable idle.

had suspicions it was MAF, someone suggested ICSV.

ran a diagnostic and it flashed up the good old 23.
although the ecu does compensate within itself for failing maf, (and wont therefore flash a CEL), a diagnostic check will show the fault code.
I believe that later "green spot" MAFs are considerably more reliable.

those of us with power FC's (and the commander unit) are able to read the voltage across the MAF and see any deterioration, otherwise I guess you rely on knocklink/lambdalink?

Sub69

All I know is that having read previous threads I was keen the change the MAF sensor regardless. I did the test where by I disconnected the MAF, and the engine continued to run as normal. I thought this meant it was knackered?



After changing it my car seemed to run better but it had not been hesitating nor did it have a noticeable flat spot before the new MAF sensor. However, I was aware of an intermittent knocking at idle on cold start before. Post new MAF sensor, I have not had the knocking. Is that just a coincidence then?

Bob Rawle

Mr Pants thats nothing to do with your maf sensor, the new age sensors are not known to fail.

GC8 cars have a habit of flashing up maf connection historic codes for no reason btw.


bob

Mr Pants!

Oh, I thought it was.

It has improved it no end, I no longer get the lift off at 4k rpm, she is smooth as you like now.

Bob Rawle

the maf is probably not the culprit, a reset would probably have done the same job

bob