mau

I think there is a leak somewhere on the hoses between the turbo and TB. How can I diagnose this? Do I have to rip every hose off and check for cracks or is there an easier way? Any sugestions would be great. The reason why I think there is a leak because I've tried different chips, different plugs, cleaned MAF, air filter, did a compression test, new O2 sensor and the car is running damn rich still. On block 032 it shows -1.2% , -21.5%, besides that I blind everyone with black smoke at WOT. Like I said before, any suggestions to help me to solve this would be nice.

Mau

Yippers®

Propane, ether etc. .. spray it lightly along hoses and connectors at idle. If you spray on a leak the revs will rise. Just be real careful

Audi2ptzero

like john and the others have used.

xr4tic

A leak would cause it to go lean.

You have the same problem my car had (still sortof has)

At part throttle cruising, the ECU was at -25%, but if I went WOT, the O2 voltages went way lean (because it was pulling 25% fuel out) and still was blowing black smoke at WOT (just on initial throttle, I think that's just something you need to live with)

So I bought a Split Second PSC1 to adjust the MAF signal (MAF vs. RPM). I had to richen it up a little at idle, and lean it out at cruising speeds. It worked great.....sort of.

So at highway speeds it was running great, but at low speeds, it would start bucking like crazy. Checked and it was running LEAN at low speeds. If I removed my fuel adjustments from the SS unit, it would run fine at low speeds, and rich at high speeds.

Turns out, turbulent air at highway speeds was messing the MAF signal up, tricking it into thinking more air was coming in than what actually was (remember my MAF and filter were in the bumper, directly in the air stream)

I took some duct tape (Is there anything it can't do?) and covered the front of the air filter up, so air couldn't ram into it and cause problems.

Problem solved. It still hiccups every now and then, and I don't like the fact I have half my air filter covered in duct tape. I'm switching to a blow-thru MAF setup, with an aftermarket MAF programmed with the appropriate transfer function.

I should hopefully have it in my hands sometime next week.

Does your air filter have an opening on the very front of it? If it does, you could try masking off the sides, reset the ECU, and see how it runs. If it doesn't, you could try masking off half the filter, reset the ECU, run it, and try rotating the filter around so the masked part faces different directions (I'd start with the masked part facing down, possibly towards the front a little.

xr4tic

but if I was (and I'll probably do) I'd get some PVC end caps the same diameter as the turbo outlet and TB inlet, thread a gauge and schrader valve (tire valve) into one end, fill it up with compressed air, and see if it leaks.

mau

<center><img src="http://pictureposter.audiworld.com/15899/mau00006_copy.jpg"></center><p>
It got me thinking...I made a big cut out on the wheel liner (nicely done with a mesh and everything) right where the air filter sits. Maybe at higher speeds it causes some turbulent air to come in to filter and give false reading on the MAF. Yes my filter has a hole in the center or on top. I'm gonna cover the wheel liner and see if anything changes. Did u have the same concept as the picture? Turbulance is not my friend? I guess the wheel spinning creates rushing wind through the hole. I think my problem is beyond that. I have been noticing a gradual loss of power. The car ran pretty strong with the same chip I have now. I have a few different chips and tried all of them with the same results, so software MIGHT not the issue here. The wheel liner thing was done over a year ago, basically when the car ran good. I'm going for more of a mechanical/leak problem. The only thing I have not checked are the hoses, even though all connectors, hoses are pretty new. I'm stuck. Need someone to shed some light in my garage.

Mau

Audi2ptzero

His short term is close to zero and it should be richer and his long term is super rich(-20%). If he had a leak before the turbo the car would run lean all the time, but that is not the case. If the leak is after the turbo the short term would be lean, because the motor is sucking air thru the leak at idle. During boost the leak would let out pressure and the car would run rich like it is. So this is why we think he has a leak somewhere between the turbo and throttle body. This leak has to be to the atmos.


You have to understand that a dbw and non dbw work completely different. With the dbw the 02 and maf work at part throttle like the non dbw, but when you go wot your non dbw stops using the maf and 02 sensors while the dbw maf is still helping to adjust the injector pulse. His car is still running very rich at part throttle and WOT.

Audi2ptzero

I know I have seen those posted here and I think charlie also tried that on his car.

Lambo-Bully

You'll need to trick the programming how ever you can to tune it specifically for however you have it set up. I've found that every bit of air has to be accounted for, so no open wastegate or blow-off valve unless you have stand alone management. Also, I'd recommend an adjustable bpv, and the australian wideband o2 monitoring setup.

What software is everyone running (chip-wise) with thier T3/T4E setups? I gotta say, the ATP chip seems to be basically to move the car. Other than that, it smokes the back bumper &amp; blows engines. I'm moving towards a partial management with an air/fuel computer, but is there a good chip out there that'll work?

xr4tic

BOTH blocks are LTFT. the first is LTFT at idle, the second is LTFT at part throttle.

STFT can be seen by watching block 033 (IIRC anyways) the percentage will always be adjusting.

Think of LTFT as a permanent base, and STFT as a temp addition. LTFT doesn't go up and down until the STFT has exceeded a certain point for a short period of time. If the STFT is running 25%, the LTFT will quickly rise to about 18-20%, and STFT will then be about 5%, and the LTFT will slowly creep up the last 5% (maybe)

I used to clear the ECU, then watch the STFT hit 29%, then watch the LTFT rise to about 20%, and then STFT drop and fluctuate between 5-10%

If the leak was before the turbo, then yes, it would run lean.

If the leak was after the turbo, it would run lean at cruising speeds (under vacuum) and run rich under boost.

I don't know how you drive, but the rest of us usually are only under boost for a very small percentage of the time we drive.
That means if it was leaking under boost (running rich) and if you were under boost for a long enough period of time to to actually cause the STFT to modify the LTFT, then as soon as you let off, and started cruising again (running lean) the LTFT would go back to adding fuel.

So no, that is not untrue.

Best thing to do is clear the ECU codes (which will reset the fuel trims) hit the highway, and cruise (stay out of boost) Datalog the STFT and LTFT (it will take a minute or two before the LTFT starts working after a reset)

My guess is it will still run rich, and LTFT will start pulling fuel out.

And I really don't see how the ECU would still modify the fuel trim under boost, the O2 sensor is only good for reading stoic (14.7:1) It's not accurate at any other ratios.
It would be really bad if it was trying to adjust the WOT A/F ratio to 14.7:1

If it really does do that, then fine, I guess that's just another reason why non-DBW is better.