Problems... Problems....
AudiWorld Super User
Joined: Nov 2000
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I've got the PES T28 chip.....
it's running good, no blown engines yet 
I can't honestly say how good, since I have a known MAF problem. Hopefully by next weekend I'll have that taken care of, so I can give a better report on the chip and how it's running.
I can't honestly say how good, since I have a known MAF problem. Hopefully by next weekend I'll have that taken care of, so I can give a better report on the chip and how it's running.
AudiWorld Super User
Joined: Nov 2000
Posts: 6,270
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My intake looks like this....
<img src="http://johnbaas.dyndns.org/latest/turbo_intake2_lo.jpg">
The problem was, the air was coming in perpendicular to the MAF at high speeds (70-80mph) and just throwing the readings off.
From what I've heard, you need at least 6" of straight pipe before and after the MAF. If you don't, then you can get bad readings. I don't have enough room for another 12" of pipe there, so I have to move my MAF
A couple things to check are the Fuel pressure and a compression test (if all the air is leaking past the rings, it could run rich)
Another possibility is a leaking injector, but that would cause it to be rich at idle, which it's not (1st field in block 032)
Try cleaning the MAF, resetting the ECU, adapting the throttle, and check the coolant and air temp sensors to make sure they are reading right (via the VAG-COM)
It could also be a bad O2 sensor. Over time they can degrade, especially if they're running really rich.
Also try blocking the filter. Have you rotated the MAF recently? The elbow behind it could cause bad readings depending on the housing rotation. It's probably not enough to cause a 20+% change though.
The problem was, the air was coming in perpendicular to the MAF at high speeds (70-80mph) and just throwing the readings off.
From what I've heard, you need at least 6" of straight pipe before and after the MAF. If you don't, then you can get bad readings. I don't have enough room for another 12" of pipe there, so I have to move my MAF
A couple things to check are the Fuel pressure and a compression test (if all the air is leaking past the rings, it could run rich)
Another possibility is a leaking injector, but that would cause it to be rich at idle, which it's not (1st field in block 032)
Try cleaning the MAF, resetting the ECU, adapting the throttle, and check the coolant and air temp sensors to make sure they are reading right (via the VAG-COM)
It could also be a bad O2 sensor. Over time they can degrade, especially if they're running really rich.
Also try blocking the filter. Have you rotated the MAF recently? The elbow behind it could cause bad readings depending on the housing rotation. It's probably not enough to cause a 20+% change though.
AudiWorld Super User
Joined: Jul 2002
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here a link to a leak detector for sale.
don't know if he's still making them.<ul><li><a href="https://forums.audiworld.com/a4/msgs/1354898.phtml">https://forums.audiworld.com/a4/msgs/1354898.phtml</a</li></ul>
AudiWorld Super User
Joined: Jun 2002
Posts: 8,421
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build a box baffle/heatshield behind the air filter
If you contain the air. You'll get a good static pressure buildup at the mouth of the inlet at speed instead of cross flow (in one side of the filter, out the other side) which will reduce inlet pressure. The box will reduce air turbulence and buffeting in the airfilter itself. The opening doesn't need to be as large as you might think. An opening about 2 to 3 times the turbo inlet area is sufficient. Make sure your air filter has maximum exposure and surface area. In this way, the box will be like the extra 6" before the MAF
Like a shoebox without the lid with the opening turned towards the front of the car.
Like a shoebox without the lid with the opening turned towards the front of the car.
Elder Member
Joined: Sep 2002
Posts: 14,366
Likes: 1
Lets remember he is driving a dbw car and you drive a non dbw
we hit full boost at part throttle and that is when he gets the puff of black smoke out the back, he also gets it when he rev matchs a down shift which also gets boost.
DBW does not use the 02 at wot, it does use the maf readings to help set the injector pulse. So that means it is running on the set fuel maps but with an adjustment from the maf.
Mau's car was running fine up on the same chip. It then started to run rich and he is just trying to figure out why. Both of his fuel trims have changed alot since it used to run good. His STFT should be around -5% and LTFT whould be around -15%, but as you can seen STFT has gone lean and LFTF has gone rich. It is just hard to acutally stay out of boost on a dbw since boost is set on motor and pedal loads with the dbw setup.
BTW john, when does a turbo car make boost? Would that be only when your on the throttle or would it actually be all the time? I am pretty sure that boost is made even when driving at part throttle. If there is a slight leak after the turbo which will have pressure between the turbo and throttle body, then the leak will let some pressure/air out before it gets to the motor and then the car will run rich since that air that is leaked out was counted by the maf.
DBW does not use the 02 at wot, it does use the maf readings to help set the injector pulse. So that means it is running on the set fuel maps but with an adjustment from the maf.
Mau's car was running fine up on the same chip. It then started to run rich and he is just trying to figure out why. Both of his fuel trims have changed alot since it used to run good. His STFT should be around -5% and LTFT whould be around -15%, but as you can seen STFT has gone lean and LFTF has gone rich. It is just hard to acutally stay out of boost on a dbw since boost is set on motor and pedal loads with the dbw setup.
BTW john, when does a turbo car make boost? Would that be only when your on the throttle or would it actually be all the time? I am pretty sure that boost is made even when driving at part throttle. If there is a slight leak after the turbo which will have pressure between the turbo and throttle body, then the leak will let some pressure/air out before it gets to the motor and then the car will run rich since that air that is leaked out was counted by the maf.
Elder Member
Joined: Sep 2002
Posts: 14,366
Likes: 1
Mau is running a dbw T28 chip for his 2000.
It ran fine before but now it is running very rich during boost and running lean a bit leaner at idle then it should be. His MAF readings might be a little low at idle but seem to be fine during boost. The problem is that at part throttle and boost the car is rich way too rich now.
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Thread Starter
AudiWorld Senior Member
Joined: Feb 2001
Posts: 900
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Re: My intake looks like this....
I already did a compression test and it was 185-190lbs across the board. Haven't checked the fuel pressure. I'm on the second O2 sensor, it has maybe 5k miles on it.