The MAF normally fails. You can try replacing it with a Mercedes MAF, which is much cheaper, and usually better than the OE bosch units.
More on that in the TDI FAQ.
More on that in the TDI FAQ.
bodley
Guest
I have the exact same problem on my 01 GOLF TDI 115. I have posted some info including the resulting VAG-COM readings in the following UK-MKIVS thread:-
http://www.uk-mkivs.net/forum/topic.asp?TOPIC_ID=27724
Mine goes in to the dealer on Tuesday and I will be posting the results on the above thread.
http://www.uk-mkivs.net/forum/topic.asp?TOPIC_ID=27724
Mine goes in to the dealer on Tuesday and I will be posting the results on the above thread.
matz
Guest
matz said:
as paulo says get a merc maf, much cheaper and should provide better top end performance, but a little loss below 2k rpm. From what you decribed above it certainly sounds like a typical dodgy maf, if when u unplug and run its fine, this is not un heard of at all they are ver very common parts to go.
The power given by limp mode is pre defined in the ECU set to run the car with minimum wear and tear to get u to a dealer.
The MAF doesnt really break down into components that go, they are small electrical sensors so part replacement isnt really an option, you have to do the whole thing.
Oh and another thing you mention at the end about getting the car hooked up for fault codes, you should alos get a log of the MAF Values and get it graphed to see if the maf is dodgy as detailed in here :-
http://www.ross-tech.com/vag-com/cars/tdi.html
all the best.
Bulldozer
Guest
Hi...i'm new around here... 
I'm (not really me, but my brother...) having exactly the same problem with a Seat Ibiza GT TDi (110): pushing the engine to around 3500/4000rpm, and the turbo fails...i say turbo because the typical "whistle" (from the turbine, i guess...) is no longer possible to hear! Besides, after that, the engine behaves as a 1.9cc with 60hp!
I've already pulled off the MAF conector (haven't driven though...), and that "whistle" can be heared when accelerating! (turbo working, right?)
So, my question is: while MAF sensor is unplugged, ECU switches to "limp mode", right? However, matz said the car ran just fine the MAF sensor unplugged (by fine, i mean with no power losses), right? but, and quoting stew:
This is what i'm twisted about What does "limp mode" consists of?? Is turbo supposed to work while in "limp mode"?? While MAF is unplugged, is the ECU running "limp mode" or it simply assumes default values and stands on default state??
Recalling what i've said before, the problem in my case is a sudden power loss with turbo "whistling" disappearing!
Tks in advance for any help
PS: prc, are you portuguese?
I'm (not really me, but my brother...) having exactly the same problem with a Seat Ibiza GT TDi (110): pushing the engine to around 3500/4000rpm, and the turbo fails...i say turbo because the typical "whistle" (from the turbine, i guess...) is no longer possible to hear! Besides, after that, the engine behaves as a 1.9cc with 60hp!
I've already pulled off the MAF conector (haven't driven though...), and that "whistle" can be heared when accelerating! (turbo working, right?)
So, my question is: while MAF sensor is unplugged, ECU switches to "limp mode", right? However, matz said the car ran just fine the MAF sensor unplugged (by fine, i mean with no power losses), right? but, and quoting stew:
This is what i'm twisted about
What does "limp mode" consists of?? Is turbo supposed to work while in "limp mode"?? While MAF is unplugged, is the ECU running "limp mode" or it simply assumes default values and stands on default state??Recalling what i've said before, the problem in my case is a sudden power loss with turbo "whistling" disappearing!
Tks in advance for any help
PS: prc, are you portuguese?
Last edited by a moderator:
OK, to clear a few things up :-
Limp mode - this is what the engine goes into if something breaks or exceeds pre set limits, this is NOT what happens when you unplug the maf.
Unplugging the maf - this means the ECU doesnt get a reading from the maf sensor and hence resorts back to default injection values pre stored in the ECU, this DOES NOT put the car into limp mode. If you get better performance on a drive with the maf unplugged then your maf if duff and needs replacement. To quote the VW TDI tech manual on this :-
Substitute function
If the air-mass flow meter fails, the control unit defaults a fixed air mass value.
This fixed value is calculated such that a reduction in engine performance can only
occur in the part-throttle range.
Bulldozer.. welcome aboard! good to have another 110 beezer around does sound like a dodgy maf you have, but really you needed to take it for a drive when you had it unplugged to test.
Limp mode - this is what the engine goes into if something breaks or exceeds pre set limits, this is NOT what happens when you unplug the maf.
Unplugging the maf - this means the ECU doesnt get a reading from the maf sensor and hence resorts back to default injection values pre stored in the ECU, this DOES NOT put the car into limp mode. If you get better performance on a drive with the maf unplugged then your maf if duff and needs replacement. To quote the VW TDI tech manual on this :-
Substitute function
If the air-mass flow meter fails, the control unit defaults a fixed air mass value.
This fixed value is calculated such that a reduction in engine performance can only
occur in the part-throttle range.
Bulldozer.. welcome aboard! good to have another 110 beezer around
does sound like a dodgy maf you have, but really you needed to take it for a drive when you had it unplugged to test.
Bulldozer
Guest
stew: that's exactly what i needed to know 
So, and concluding, when the turbo fails (or when i can't hear it "whispling"), it means the ECU had gone into "limp mode", right?
Anyway, i'll have a ride with the maf unplugged asap, to clarify things out! Thanks for your precious help
That's what i suspected! Seems like we are compatriots
A proposito, o teu mail [email protected] tem alguma coisa a haver com a BTTerra ali perto da Batalha??
So, and concluding, when the turbo fails (or when i can't hear it "whispling"), it means the ECU had gone into "limp mode", right?Anyway, i'll have a ride with the maf unplugged asap, to clarify things out! Thanks for your precious help
prc said:Half of me is.I live in Portugal though..
That's what i suspected! Seems like we are compatriots
A proposito, o teu mail [email protected] tem alguma coisa a haver com a BTTerra ali perto da Batalha??
Bulldozer said:That's what i suspected! Seems like we are compatriots
A proposito, o teu mail [email protected] tem alguma coisa a haver com a BTTerra ali perto da Batalha??
I most certainly do.. You can also pick em up @ Power e Speed (also nearby). If that's to close for you, you'll also find me in Lisbon (every day of the week).
matz
Guest
Just having a read of this and thinking of Bulldozer in particular. When I drove with the MAF unplugged, it was without a doubt faster THAN when the power had fallen off previously. BUT, it wan't quite as fast as with the engine running as it is now!!!
As its running at the moment, there seems hardly anything wrong with it. The MAF is the original one and is connected. Good acceleration and punchy performance throughout the range and no power dropping off. I've done nothing to the car apart from unplug and run without the MAF, giving it a good blast though in the process!
So until it goes slow again, alls well!
As its running at the moment, there seems hardly anything wrong with it. The MAF is the original one and is connected. Good acceleration and punchy performance throughout the range and no power dropping off. I've done nothing to the car apart from unplug and run without the MAF, giving it a good blast though in the process!
So until it goes slow again, alls well!
matz
Guest
Bulldozer
Guest
Well...i've been checking the car again with my brother, and we've just found the MAF was manufactured by Pierburg, which, according to TDI FAQ, are extremely reliable and is unlikely to be the source of the problem!
In addition, my brother has remembered an interesting story: some months (maybe 1 or 2 years) ago, the car had ran into the exactly same problems! Fortunately, he had to make some long trips, which were done at 90/100mph average!! Since then, problems were gone!! Why? We are wondering on the possibility of the VNT mechanism to get sticked! The car is used mostly in urban routes, and probably there is a large amount of soot build-up in the exhaust, causing the variable-vanes to malfunction...
So, is there any reliable and cheap way to clean the mechanism at the garage, or is a strong blast and/or squeeze the best way to go??
Thanks for the help given so far Cheers!!
---
prc: Power e Speed is nearby what?? BTTerra?? The bicycle store?? If so, i can tell you i'm really near you ehehe! Hugs!!
In addition, my brother has remembered an interesting story: some months (maybe 1 or 2 years) ago, the car had ran into the exactly same problems! Fortunately, he had to make some long trips, which were done at 90/100mph average!! Since then, problems were gone!! Why? We are wondering on the possibility of the VNT mechanism to get sticked! The car is used mostly in urban routes, and probably there is a large amount of soot build-up in the exhaust, causing the variable-vanes to malfunction...
So, is there any reliable and cheap way to clean the mechanism at the garage, or is a strong blast and/or squeeze the best way to go??
Thanks for the help given so far
Cheers!!---
prc: Power e Speed is nearby what?? BTTerra?? The bicycle store??
If so, i can tell you i'm really near you ehehe! Hugs!!
Bulldozer said:Well...i've been checking the car again with my brother, and we've just found the MAF was manufactured by Pierburg, which, according to TDI FAQ, are extremely reliable and is unlikely to be the source of the problem!
In addition, my brother has remembered an interesting story: some months (maybe 1 or 2 years) ago, the car had ran into the exactly same problems! Fortunately, he had to make some long trips, which were done at 90/100mph average!! Since then, problems were gone!! Why? We are wondering on the possibility of the VNT mechanism to get sticked! The car is used mostly in urban routes, and probably there is a large amount of soot build-up in the exhaust, causing the variable-vanes to malfunction...
So, is there any reliable and cheap way to clean the mechanism at the garage, or is a strong blast and/or squeeze the best way to go??
Thanks for the help given so far
---
prc: Power e Speed is nearby what?? BTTerra?? The bicycle store??
It is very easy for the VNT mechanism to get stuck especially if running urban routes and/or slow driver (to be politically correct and not use w*men)..
If you give it a good run you might be able to clean it out a bit. Other than that you'll have to take out the turbo and have it cleaned, which is expensive (around 300-350Eur).
The Pierburg is good, but that does not mean that it won't fail..
Yes, Power e Speed is close to BTTerra which is also pretty close to where I live..
I live in Sao Pedro de Moel..
yep by the sounds of it then a sticky VNT could also be the cause for a few of these which isnt unheard of either, have read this quite a few times over on tdiclub.com , so i would try a and good hard blast to try and free the system up and also get some lube down the wastegate arm (this is detailed in the tdiclub site, do a search or post up) if this doesnt solve it then it will have to be a turbo off and clean jobbie as paulo says.
Same problem - Sudden loss of power
Hi, Please let us know if changing the maf fixes your prob.
My car has been in for body repair for two months, previously no problems at all. Nothing in the engine bay was damaged, just the doors being replaced (idiot in minibus on country lane!!)
Since I had the car back last weekend, have lost power suddenly on dual carriageway, when giving it some beans, got to about 80 then suddenly felt like no bopost at all. Still drives fine, but massive loss of power, top speed about 80. I was low on fuel, so stopped for a top up, thinking vague chance of fuel starvation, after that the car ran fine. Next day, the same thing happened, when I pulled up at lights I switched off the engine and restarted, then fine for the rest of the 30 mile journey. It has not happened again for a couple of days.
Could the car being standing undriven for two months have caused a temporary sticky turbo? Does anyone have a VAG-COM they could let me use somewhere near Norwich? (I am near North Walsham)
Thanks!!
(Tdi 110 2002 Upsolute, 60,000 miles, no problems previously, re-mapped since 20,000 miles)
Hi, Please let us know if changing the maf fixes your prob.
My car has been in for body repair for two months, previously no problems at all. Nothing in the engine bay was damaged, just the doors being replaced (idiot in minibus on country lane!!)
Since I had the car back last weekend, have lost power suddenly on dual carriageway, when giving it some beans, got to about 80 then suddenly felt like no bopost at all. Still drives fine, but massive loss of power, top speed about 80. I was low on fuel, so stopped for a top up, thinking vague chance of fuel starvation, after that the car ran fine. Next day, the same thing happened, when I pulled up at lights I switched off the engine and restarted, then fine for the rest of the 30 mile journey. It has not happened again for a couple of days.
Could the car being standing undriven for two months have caused a temporary sticky turbo? Does anyone have a VAG-COM they could let me use somewhere near Norwich? (I am near North Walsham)
Thanks!!
(Tdi 110 2002 Upsolute, 60,000 miles, no problems previously, re-mapped since 20,000 miles)
Almost certainly overboosting if switching off and restarting is a temporary fix.
Try hosing down the VNT actuator rod linkage with WD40, it can sometimes work ... try not to get it into the vacuum actuator itself tho'
Try hosing down the VNT actuator rod linkage with WD40, it can sometimes work ... try not to get it into the vacuum actuator itself tho'
WD 40 (Probably!) Fixes Everything!!
Well I just took off my engine cover, and after some groping around and declamping the air inlet hose, I found the turbo actuator arm. (Not before I dropped one of the bolt covers from the engine cover into the engine compartment onto the engine shield Grrr!)
I fiddled a bit and it moved a few mm up and down but felt rather 'graunchy'. I could hear a hiss as I moved it suggesting air moving as I moved the diaphram in the actuator body. I sprayed this part liberally with WD40 - hoping it would not catch fire later! I also sprayed the air shut-off thingy on the top back left of the inlet gubbins (technical eh?!).
Then got my wife to rev the bugger up to 4-5k a few times after tickover for a minute - I could then hear the turbo whistling up much louder than in previous months.
So, took of the engine shield, got the bolt cover out, split open my finger on the sharp edges putting it back!! (It was cold, so painless, but only 'till my hands warmed up!)
I have just taken the car out and WOW!! I really didn't expect this to work - sorry Craig - just anticipated a big bill and maybe should I sell the car! But, the tickover is now rock steady and smooth. the power 'feed-on' is as good as it ever was when the car was a few years younger and throttle response is better. I just did some slightly illegal driving on some wide A roads near me and got to near top speed with no problems and VERY quick.
No limp mode. I did lots of slowing and accelerating, hard booting and gentle booting up to high speed and no sign of any trouble. Of course this doesn't mean it may not happen tomorrow on the way to work but it feels different. Its crazy that this actuator arm is so critical and yet it's exposed and rusty etc. I don't see it mentioned in the maintenance schedule at all. When it goes in for a cam belt next week I am going to ask the deale rto clean and lube the actuator arm properly too, as they will have the bits all off the engine side anyway.
Thanks Craig - I hope the problem is now fixed. No MAF needed after all! (Oh I did try disconnecting it and driving a little without it earlier, drove like a complete dog!
Well I just took off my engine cover, and after some groping around and declamping the air inlet hose, I found the turbo actuator arm. (Not before I dropped one of the bolt covers from the engine cover into the engine compartment onto the engine shield Grrr!)
I fiddled a bit and it moved a few mm up and down but felt rather 'graunchy'. I could hear a hiss as I moved it suggesting air moving as I moved the diaphram in the actuator body. I sprayed this part liberally with WD40 - hoping it would not catch fire later! I also sprayed the air shut-off thingy on the top back left of the inlet gubbins (technical eh?!).
Then got my wife to rev the bugger up to 4-5k a few times after tickover for a minute - I could then hear the turbo whistling up much louder than in previous months.
So, took of the engine shield, got the bolt cover out, split open my finger on the sharp edges putting it back!! (It was cold, so painless, but only 'till my hands warmed up!)
I have just taken the car out and WOW!! I really didn't expect this to work - sorry Craig - just anticipated a big bill and maybe should I sell the car! But, the tickover is now rock steady and smooth. the power 'feed-on' is as good as it ever was when the car was a few years younger and throttle response is better. I just did some slightly illegal driving on some wide A roads near me and got to near top speed with no problems and VERY quick.
No limp mode. I did lots of slowing and accelerating, hard booting and gentle booting up to high speed and no sign of any trouble. Of course this doesn't mean it may not happen tomorrow on the way to work but it feels different. Its crazy that this actuator arm is so critical and yet it's exposed and rusty etc. I don't see it mentioned in the maintenance schedule at all. When it goes in for a cam belt next week I am going to ask the deale rto clean and lube the actuator arm properly too, as they will have the bits all off the engine side anyway.
Thanks Craig - I hope the problem is now fixed. No MAF needed after all! (Oh I did try disconnecting it and driving a little without it earlier, drove like a complete dog!
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