big matt Posted April 9, 2008 Report Posted April 9, 2008 Hi all, 2002 tdi 115 alhambra, recently noticed seems very sluggish After 3000 RPM (as if the turbo is no longer there although it does eventually get to around 4000rpm any idea's (still got some ummff low range)?_ No codes present !Swopped maf Made no difference Cheers Matt Quote
Dodger Posted April 10, 2008 Report Posted April 10, 2008 Another duff MAF ??? Did you get it from ebay? Lack of any fault code points towards MAF. Quote
Smilge Posted April 10, 2008 Report Posted April 10, 2008 If it was the MAF then it would appear to be sluggish at all revs and a bit rough on idle .... I reckon Tims right and the turbo vanes are not opening to there limit. Might be worth checking the amount of VNT actuator movement you are getting. I'm surprised it's not going into limp mode though. Have you also had a look at the TMAP sensor to see if that needs a clean? Quote
stevie m Posted April 10, 2008 Report Posted April 10, 2008 (edited) I had the same problem with mine. Mine would accelerate ok up to 300 rpm then slow right off and in the higher gears it would not go over 3000-3500 rpm and top speed could not be attained ( i was told :16: ).I thought it was turbo related and looked into cleaning it. I never got round to it as i got rid of it in the end before i could do it (problem solved :16: ). I don't think it will be maf related as i change mine and there was no change in the performance. I also felt i was losing a bit of fuel economy althought it had done 167000 miles (i was certainly losing coppers from my Pocket bl***y fuel prices). Having said that when my maf went the car would only do 80 but i had a code on my reader ! Edited April 10, 2008 by stevie m Quote
big matt Posted April 10, 2008 Author Report Posted April 10, 2008 If it was the MAF then it would appear to be sluggish at all revs and a bit rough on idle .... I reckon Tims right and the turbo vanes are not opening to there limit. Might be worth checking the amount of VNT actuator movement you are getting. I'm surprised it's not going into limp mode though. Have you also had a look at the TMAP sensor to see if that needs a clean?I'm lost now whats a VNT actuator movement? How do icheck it ?Its all fully serviced! Every filter replaced about a month ago.The maf i've tried was off my mates galaxy that working fine.Is there an easy way to clean the turbo vanes ?I haven't checked the vacpipes yet but will be doing later THANKS FOR ALL YOUR SUGGESTIONS KEEP EM COMING!!!!! Quote
tiny Posted April 10, 2008 Report Posted April 10, 2008 A knackered cat is another possible, once the guts collapse they restrict the exhaust gases, although mines a petrol I imagine the same occurs when a diesel cat "dies". Get underneath and give it a good thump, if theres noise in there (thud etc) then its knackered. Quote
Dodger Posted April 11, 2008 Report Posted April 11, 2008 Big Matt, How long has the car been like this? Did it suddenly go wrong or has it deteriorated over a period of time. Have you owned the car from brand new, do you know the history of the car? How many miles has it done? Regarding the VNT mechanism in the turbo, the vanes move to increase the boost at low revs and move back to decrease the boost at high revs. The idea is that you get plenty of pull from the engine across the whole rev range. Older diesel engines with fixed turbos suffered from "all or nothing" where the was no pull at low revs and then they would suddenly take off as you accelerate above 2000 rpm. If the VNT mechanism sticks it usually results in too much boost and the engine trips into limp mode and you get a fault code. Quote
big matt Posted April 11, 2008 Author Report Posted April 11, 2008 Big Matt, How long has the car been like this? Did it suddenly go wrong or has it deteriorated over a period of time. Have you owned the car from brand new, do you know the history of the car? How many miles has it done? Regarding the VNT mechanism in the turbo, the vanes move to increase the boost at low revs and move back to decrease the boost at high revs. The idea is that you get plenty of pull from the engine across the whole rev range. Older diesel engines with fixed turbos suffered from "all or nothing" where the was no pull at low revs and then they would suddenly take off as you accelerate above 2000 rpm. If the VNT mechanism sticks it usually results in too much boost and the engine trips into limp mode and you get a fault code.Cars been like this for about a week, it didn't just stop performing whilst driving its done it over night, before that it was fine. i've owned it for about a year its dome 130k full dealer history. I have tried to thrash it !!! but makes no difference. thou it does seem to go better one minute then when i use it again its guttless Quote
Dodger Posted April 12, 2008 Report Posted April 12, 2008 So one day it was fine, then suddenly the next day it's not going right. Don't really know what to suggest. It sounds a bit like a failure of the elctronics, it's odd that you don't get any fault code. Perhaps you could try driving it with the MAF disconnected to see if that makes any difference. Are you using VAG COM and laptop PC to read the fault codes? Can you see that it is communicating with all the car's electronic modules? Quote
gio Posted April 12, 2008 Report Posted April 12, 2008 (edited) Hi all, 2002 tdi 115 alhambra, recently noticed seems very sluggish After 3000 RPM (as if the turbo is no longer there although it does eventually get to around 4000rpm any idea's (still got some ummff low range)?_ No codes present !Swopped maf Made no difference Cheers Matt Next time it does it, pullover and switch off.Then re start if it feels better and revs beyound 3000rpm in 2nd gear then the car went into a limited function mode so to speak,possible due to overboosting. this can be caursed by a few things as mentioned already sticking vanes to the actuator not working properly. this could be due to the n75 control valve packing in this is an easy check so to speak just do a search of n75 control valve. dam just done a check.. nothing on the n75.......visit here.. usefull site http://forums.tdiclub.com/ Edited April 12, 2008 by gio Quote
big matt Posted April 14, 2008 Author Report Posted April 14, 2008 after another 300 miles run at the weekend, I was playing with the turbo by keeping the revs low then drop it down the box and get the revs high, for most of the way, (Reason being i thought if the revs are high it sould make the turbo vanes open more etc, probly wrong but i trid it )seems to be better but still not right. managed to get, lets say a 3 figure number from the speedo ;-) Quote
dpm Posted April 14, 2008 Report Posted April 14, 2008 I must seem very Staid. But I would rarely rev over 3k anyway. I certainly don't drive at those revs. (75mph is approx 2200rpm in sixth. I don't actually know what happens if I revved that hard!! D Quote
NikpV Posted April 14, 2008 Report Posted April 14, 2008 I must seem very Staid. But I would rarely rev over 3k anyway. I certainly don't drive at those revs. (75mph is approx 2200rpm in sixth. I don't actually know what happens if I revved that hard!! D you will be a prime candiadate for needing your turbo cleaned then according to the latest thoughts on the matter ;) Quote
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