75bhp 146ftlb after remap!!!!!!!!

[audia21991]

Right here we go, please bare with me!

Firstly, as some of you may of read from previous posts, I've had a problem with the turbo cutting out for quite a while now. It was solved briefly when she went in for her last service, the turbo was cleaned and the problem didn't reoccured for 3ish months. However it started happening again and it also brought about a loss of power, as if the remap had switched itself off.

I booked up an appointment with pragmatik ict (revo) and went today. After a couple of hours tinkering with diagnostics and the like, it seems that the car in stock mode is seriously down on power/torque. When the remap was turned on you noticed a definate increase in performance but the car was only producing 146lb-ft!!!!!!!!!!!! 2 more than what it should be in stock, nowhere near the quoted 182lb-ft for a revo map. The stock figures must really be awful :( Mike from pragmatik ict called a few contacts at revo and audi and it seem the power problem could be down to 1 of 3 things:

N75 valve
EGR
turbo

Seeing as I already have a problem with the turbo cutting out i think it's likely to be the source of a lack in grunt. Does anyone have any ideas about these things and I would really appreciate it if someone could give me a rough idea of the cost of replacing each of these things. I think i've read about replacing the turbo with polo 1.4tdis turbos to keep the price down?

Any help will be greatly appreciated.

Edd.

[Lee S]

It's not the inter-cooler leaking is it? I would imagine that a competent tuner would be able to spot that, but that's what was causing drastic power loss with mine before it was replaced. Worth a quick visual check to see if there are any dirty streaks or bulging seams/o-rings on it.

HTH

[dan_b]

Exactly what I was going to say - boost leak probably from the intercooler, which may be physically cracked, or else a split hose feeding.
If it's not that, other prime suspects for me would be:

Dodgy MAF (mine was dodgy but Revo spotted it when it was being remapped)
Failing injector loom.

[audia21991]

Hey,
checked the MAF and it was all ok, I will check the intercooler for marks today.
Could you let me know how much the N75 valve, EGR and turbo should be to replace? I don't want to be taken for a ride when I take her to the garage!

Thanks,
Edd.

[Bluefox]

It's not the inter-cooler leaking is it? I would imagine that a competent tuner would be able to spot that, but that's what was causing drastic power loss with mine before it was replaced. Worth a quick visual check to see if there are any dirty streaks or bulging seams/o-rings on it.

HTH

I was wondering that, it seems as though the A2 can pop its 'cooler when remapped... according to a remap tech I was speaking to the other day.

Experienced the same power loss on standard though - until I diagnosed a popped intercooler.

[tbm1397]

I would also say check your intercooler.. had the same prob with another car and it turned out that the end cap on the cooler had a crack in it..

[audia21991]

Turns out the problem was the turbo $$$ :( Garage are going to keep her in for a week.
£645 total, i've seen worse new turbo prices i guess :o Can't wait to feel the quoted 182lbft now (hopefully :o)!!!

[dan_b]

What did they say was actually wrong with the turbo and how did they diagnose it - physical faults with turbos are rare indeed. Have you booked it in already - I'd get a second opinion if I were you before you commit to that level of spend.

[audia21991]

Well the garage asked me to go in tomorrow so they could show me the problem, by show I guess it is a physical fault. The garage ( P. Breading Motor Services) was recommended by Southend Audis parts department, so hopefully theyre not the type to try it on!
Will post again once I know the exact problem :)

[dan_b]

Well, take what they say with a bit of a health warning before committing the spend - get pictures if you can to post back to the forum and certainly any fault codes they've pulled off the ECU.

[audia21991]

Went to the garage today, they had another A2 in for service!! Nobodys on here I think.
I don't really understand how the turbo works but apparently the vacuum pressure is good but the actuator and linkage has partially ceased and sometimes does cease (hence the turbo cutting out in 5th about 50mph sometimes). I have very limited knowledge of this so i'm not even sure if that made sense! The garage seems very friendly and have had experience with A2's so I've booked it in for the new turbo :)

[dan_b]

I dont understand their diagnosis. A Turbo is just a pump that uses the energy in the exhaust gas to spin a turbine wheel which compresses the incoming air to increases the amount of air and fuel in the engine to give you more power . No vacuum involved! Hope it fixes the issue for you.

[Lee S]

Would that be the pressure at the wastegate actuator? Surely if the wastegate actuator is all that has seized, then a new actuator would be cheaper than a whole turbo? I don't know what kind of turbo the Audi uses though. Maybe it isn't any of the usual brands and has no user replaceable parts on it. I bought an actuator for a Garrett T3 on my Lancia Delta Integrale and it was about 20 quid at the time. Strange.

EDIT::: Just found a turbo for an A2 1.2 TDI on eBay DE and it states that it is a Garrett. I am sure you could just get a wastegate actuator for it.

EDIT #2::: Dan - the pressure from the intake side of the turbo feeds a wastegate actuator which basically controls the flow of gases through the turbine. This prevents the turbo from over-boosting. If the boost gets too high, the waste gate opens and the turbo slows and pressure drops. This is a constant process. If the wastegate is faulty then it will either be stuck open and you wont get any boost or stuck shut and you will get permanent over-boost. HTH.

Diagram here (http://www.lotusespritturbo.com/Garrett_AiResearch_T3_Turbocharger.jpg)

Maybe the actual wastegate is faulty and not the actuator. Good luck with the repair though.

[dan_b]

Lee you beat me to it I was going to post about the wastegate as a follow up I too wonder if that might be the problem

[spike]

On the 75hp TDi engine, wastegate operation is a bit more complex than shown in the diagram provided by Lee.
Turbo boost pressure is measured by sensors which communicate with the engine ECU. The ECU then activates the N75 charge pressure control solenoid valve which meters boost pressure to the wastegate. The wastegate then functions exactly as described in LEE's 'Edit#2' description above.
A faulty N75 valve or a crushed or split signal line to the N75 valve would give the same symptoms as a stuck wastegate.
Hopefully the garage will have done a diagnostic scan and visually inspected the pipework to the N75 valve to eliminate these possible faults before changing the turbo

Cheers Spike

[Lee S]

Interesting. Thanks Spike. So it is almost like a "fly-by-wire" system. Even the wastegate actuator is electronically controlled. I guess all these things go toward better performance and economy.

Thanks,

[dan_b]

Yes its to give the ecu a proper feedback control loop on the wastegate a good idea. Ive seen N75 failures on turbo Audis before including my old S2 so its worth considering.

[audia21991]

Got an unexpected call from the garage today to say the whole turbo didn't need to be replaced and it was just the linkage! So the damage was a much easier £195!!!
The car now feels amazing, especially 2nd gear, much much quicker! Really impressed :D:D:D:D:D
I'm glad the problem has finally been solved!

Thanks for all your help :)

[Lee S]

Excellent news!! :D:D

[audia21991]

Out of interest, does any1 know how likely it is for the linkage to sieze up again (its the same part just cleaned)? Or does it depend on the quality of repair?

Edd.

[dan_b]

I dont know what part they are actually describing when they say turbo linkage do you have any more info? Pictures or part numbers of what as replaced?

[audia21991]

Im afraid i dont have any part numbers, but the linkage wasn't replaced it was just cleaned/refurbed, hence the (unnecessary?) worry of it ceasing again. I know that the turbo linkage on the 3-cyl turbo is external whilst the 4-cyl is internal. Hopefully it wont but if it does at least I know the exact problem :o