Cleaned my MAF - big difference (996TT)
Discussion
I guess being a MAF its probably relevant to other 996/993 models....
My car has been running a bit rough lately, jerky at low speeds in 1st & 2nd and also when on the move (for example staying in gear & easing off the gas then re-applying gas the car felt very jerky)
Had suspected the MAF & indeed advice on here was check this first, so decided to clean it rather than spend £400+ having a new one fitted by my OPC.
In fact the problem had been pointed out to them at the last service but whan I collected it I was told that there was nothing wrong with it. Well I knew better, I mean you just know when your car isn't running right - I think we all do.
So cleaned the MAF using a electronic circuit cleaner with instructions given to me on this board & the difference is amazing. The car now runs so smooth & all the above mentioned problems have gone.
So very pleased....total cost £12 (cleaner & torx bit)
Just thought I would pass this on in case anyone else was experiencing these problems.
ta
R.
My car has been running a bit rough lately, jerky at low speeds in 1st & 2nd and also when on the move (for example staying in gear & easing off the gas then re-applying gas the car felt very jerky)
Had suspected the MAF & indeed advice on here was check this first, so decided to clean it rather than spend £400+ having a new one fitted by my OPC.
In fact the problem had been pointed out to them at the last service but whan I collected it I was told that there was nothing wrong with it. Well I knew better, I mean you just know when your car isn't running right - I think we all do.
So cleaned the MAF using a electronic circuit cleaner with instructions given to me on this board & the difference is amazing. The car now runs so smooth & all the above mentioned problems have gone.
So very pleased....total cost £12 (cleaner & torx bit)
Just thought I would pass this on in case anyone else was experiencing these problems.
ta
R.
Dunno if Porsche is the same, but if you are Mercedes, you do the following:
1) Buy ship load of hot wire airflw sensoors from Bosch;
2) Stamp MB part number on it;
3) Think of a number and multiply the cost by 3.
The MAF went in my E Class a while back. New part cost was over £300, but I was stuck and didn't know any better.
You can actually buy them direct from Bosch for just over a ton. Torx screwdriver and you're sorted.
Its robbery.
1) Buy ship load of hot wire airflw sensoors from Bosch;
2) Stamp MB part number on it;
3) Think of a number and multiply the cost by 3.
The MAF went in my E Class a while back. New part cost was over £300, but I was stuck and didn't know any better.
You can actually buy them direct from Bosch for just over a ton. Torx screwdriver and you're sorted.
Its robbery.
rumplestiltskin said:Guess so.
I suspect its the same story with Porsche, thieving g1ts.
R.
From what I've read, once they start to break down, its a slippery slope and I've not read of a cleaning method that has worked 100%.
Best bet is to check (if you can), find a Bosch part number on the MAF itself, then look on Ebay. Expect to pay between £60 - £100.
HTH,
Greg
MAFs are horribly unreliable and I understand wouldn't be needed if there was less pressure from the (environ)mentalists on car manufacturers to have closed loop systems.
Bikes know from fuelling maps what mass of air will be going in for certain throttle, engine revs, temperature etc, so they can put in the right amount of fuel.
MAFs are supposed to report to the ECU the actualy mass of intake air (saving it from calculating it) but they don't last long (my M5's had gone within 25k miles) and when they go wrong they tend to underread making the engine go lean high up.
I'm really expecting a big deal to come of this now that pretty much every new car has them fitted, they'll have to get way cheaper and become service items, say 24k miles. IMHO
I'm thinking of putting a new one on my 20k mile 996 just as a matter of course.
>> Edited to add...
I reckon the only reason the MAF debacle hasn't blown up is because the majority of people couldn't care less if their engines are making 60% of rated output since they never rev them up / go outside a town.
SM
>> Edited by supermono on Monday 9th January 13:45
>> Edited by supermono on Monday 9th January 15:01
Bikes know from fuelling maps what mass of air will be going in for certain throttle, engine revs, temperature etc, so they can put in the right amount of fuel.
MAFs are supposed to report to the ECU the actualy mass of intake air (saving it from calculating it) but they don't last long (my M5's had gone within 25k miles) and when they go wrong they tend to underread making the engine go lean high up.
I'm really expecting a big deal to come of this now that pretty much every new car has them fitted, they'll have to get way cheaper and become service items, say 24k miles. IMHO
I'm thinking of putting a new one on my 20k mile 996 just as a matter of course.
>> Edited to add...
I reckon the only reason the MAF debacle hasn't blown up is because the majority of people couldn't care less if their engines are making 60% of rated output since they never rev them up / go outside a town.
SM
>> Edited by supermono on Monday 9th January 13:45
>> Edited by supermono on Monday 9th January 15:01
Well rather than go Christmas shopping I decided to clean my MAF sensor as I had recently re-oiled my BMC filter as rumour has it MAFs don't like filter oil.
So I spent a whole day trying to find the right stuff. And where did I end up?? 'Kin Halfords - £4.99 a can I think. You can also get it in Maplins so I'm told.
You want the non-residue stuff. I actually rang the manufacturer (tel no was on the can) who makes the stuff for Halfords just to double check.
And the difference after spraying gallons of the stuff on my MAF?????
None whatsoever !
So I spent a whole day trying to find the right stuff. And where did I end up?? 'Kin Halfords - £4.99 a can I think. You can also get it in Maplins so I'm told.
You want the non-residue stuff. I actually rang the manufacturer (tel no was on the can) who makes the stuff for Halfords just to double check.
And the difference after spraying gallons of the stuff on my MAF?????
None whatsoever !
Filter oil is definitely said to foul the sensor, whether it does or not I wouldn't like to say. With my new MAFs (M5) the difference wasn't immediate but I guess the engine had to adapt to them, then it was stonking.
It may be that your MAF is beyond repair (if it's even gone).
Why are you suspecting it? Have you been on the dyno?
Andy
It may be that your MAF is beyond repair (if it's even gone).
Why are you suspecting it? Have you been on the dyno?
Andy
pdV6 said:
Alfas also use Bosch MAFs and they fail with alarming regularity, costing £££s to replace at main dealers.
German parts causing Itialian horror stories... who'd have thought it?
>> Edited by pdV6 on Monday 9th January 12:31
My discovery also has a Bosch MAF and is now on its 3rd in 3 years!!!! aparently TD4 freelanders also eat bosch MAf's
German engineering making landrovers unreliable, what ever next Mercs that breakdown
oH they do 
egbert said:
What cleaner did you use?
I used "Electronic Solvent cleaner Plus" part number : ERECSP200D bought from RS.
I rang the manufacturer to check if its ok to use on plastics, which it is, it also leaves no residue.
If its a 996TT you will need (prob same for all 996's) a T-20 torx bit to unscrew the MAF.
R.
>> Edited by rumplestiltskin on Monday 9th January 16:42
2002 996 tt MAFs are 255.37+vat from a UK OPC.
The guy at the place I spoke to said they're changed if they go faulty and the ECU tells of the fault. In my case (M5 again) they found no fault and swore up and down they would be logged if faulty.
Eventually they were changed since I was making a fuss, difference was night and day. QED: they were busted.
So it seems Porsche's line is the same: "ECU will report a fault", except it won't unless it's truly shafted. Dyno run will reveal the fault -- my M5 test was aborted because of lean running.
SM
The guy at the place I spoke to said they're changed if they go faulty and the ECU tells of the fault. In my case (M5 again) they found no fault and swore up and down they would be logged if faulty.
Eventually they were changed since I was making a fuss, difference was night and day. QED: they were busted.
So it seems Porsche's line is the same: "ECU will report a fault", except it won't unless it's truly shafted. Dyno run will reveal the fault -- my M5 test was aborted because of lean running.
SM
I had my 996TT dynoed at 422 bhp (2 runs) at £30K miles and on original MAFs. Engine is stronger and smother now on the same MAFs than then, but does suffer some (intermittent) low rev grumpiness and has now done £55K miles now. Maybe I am not a one off ?
Where is the MAF - I fancy cleaning it if it is this easy and beneficial.
>> Edited by cyrus1971 on Monday 9th January 16:50
Where is the MAF - I fancy cleaning it if it is this easy and beneficial.
>> Edited by cyrus1971 on Monday 9th January 16:50
GregE240 said:
Dunno if Porsche is the same, but if you are Mercedes, you do the following:
1) Buy ship load of hot wire airflw sensoors from Bosch;
2) Stamp MB part number on it;
3) Think of a number and multiply the cost by 3.
The MAF went in my E Class a while back. New part cost was over £300, but I was stuck and didn't know any better.
You can actually buy them direct from Bosch for just over a ton. Torx screwdriver and you're sorted.
Its robbery.
Funny thing is that I bought a Merc MAF to fit my Golf as the MB one was £60 compared to £240 from VW!!!
It's on the intake at the top just after the point where the outlets from the turbos combine.
I would tend to buy a new one if I thought the old one was faulty -- the Bosch engineer who tested the ones on my M5 said cleaning them can be "dangerous". Could be he was just playing his "I know more about this than you do so I'll talk to you like you're an eejit" card, I don't know, but since they have a drastic effect on mixture I'd rather avoid a lean condition on a turbo engine at all costs -- especially if there's a warranty issue to think about.
Frankly, if they ran your car on the dyno (ie it didn't go dangerously lean at the top) and it made that sort of power I'd leave well enough alone, or just buy a new one out of interest.
SM
I would tend to buy a new one if I thought the old one was faulty -- the Bosch engineer who tested the ones on my M5 said cleaning them can be "dangerous". Could be he was just playing his "I know more about this than you do so I'll talk to you like you're an eejit" card, I don't know, but since they have a drastic effect on mixture I'd rather avoid a lean condition on a turbo engine at all costs -- especially if there's a warranty issue to think about.
Frankly, if they ran your car on the dyno (ie it didn't go dangerously lean at the top) and it made that sort of power I'd leave well enough alone, or just buy a new one out of interest.
SM
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