sanadrustom

Okay so I'm done reading for the past two weeks and time to get the help of experts on here.

i have a 2004 a4 1.8T (auto tranny), and the issue I am having with it is that it has no power. let me give a scenario...lets say I'm at a red light and step on it, I'm talking pedal to the floor, the car doesn't move like its a turbo car. it eventually gets to high revs and eventually throws CEL with P0299 code (oddly enough more often than not when going up hill if that counts for anything).

I have read anything from vacuum leaks to waste-gate flap and everything in between. the car has 120k miles on it, and I am in the process of figuring it out as it gets warmer outside. my question is what the best starting point? or should I wing it with random parts replacements? From the things i read i could replace 1 part or hose and get lucky and its all fixed or its going to be a hunt, either way i want it fixed.

please do advise me as i am tired of being beat by 98 hp civics lol

ps. i am mechanically inclined so don't hesitate to recommend anything

Cheers and thank you

lyleswk

First, any recent maintenance / repairs?

Below is the ross tech troubleshooting guide. I would go in that order except don't assume there is a turbo problem until last. The good news is, it should be something only on the charge side...

16683/P0299/000665 - Ross-Tech Wiki

sanadrustom

i have done spark plugs last weekend, thought it was doing the same things before and after it did make it start better.

i will be replacing the DV this weekend as a start. as for vacuum hoses aside from the carb cleaner check for leaks anything you recommend?

Thanks

sanadrustom

I just got to the car parked between two trucks

When I rev it I hear a rattle type sound and when I lift between revs I hear almost a ticking sound or a backfire but sounds like its inside the cat

Could it be a bad cat? Would it produce P0299?

sanadrustom

I narrowed it down to this area

Is that wastegate flap?

sanadrustom

So it's the Watergate I have bought a new turbo this morning and will be putting it in the day I get it

Dealership wanted two arms and a leg for parts and labor so suffice to say I'm doing it myself and doesn't seem to hard for a job

steveracer

I had the wastegate flap nut back off/crack off/disappear from my 1.8t and the car had basically no boost. If you can put your hand and feel under the exhaust manifold or turbo, there is a long rod with an adjustment nut on it. There should be a nut on the end farthest rearward in the car. If missing, you may have found your problem. If you can't reach it, try a mirror and see if it is there. May require removing the intake box.


Note, I only saw original post and not replies due to a viewing option, such as hybrid mode on this forum. Anyway, hope all went well. Likely you didn't need a new turbo (like me - but I replaced it anyway) just a new adjustment nut.

sanadrustom

The update

So finally I'm back from vacation and have installed the new turbo and all that good stuff. But I have ran into a problem...

I now have code P0234. Which is over boost which is the opposite of what I had previously.

I'll try to describe what I hear to maybe narrow it down.. Car idles fine and no issues there, when you first start from a stand still you get boost and feels great for about 1000rpms then you hear air being let out like a leak sound and all boost is gone.

Mind you I'm sure it's something as stupid as me forgetting to tighten something or connected the n75 wrong or a wrong house in the wrong spot. I'm convinced that's what I did, and will look at it this up coming weekend. My question is, any one had any other ideas? Or have I done something extremely wrong and will me driving it like this kill the turbo \engine?

Ps the waste gate flap was toast on the old turbo

Thanks for the help

sanadrustom

One other thing....when I was swapping fittings for the oil and coolant I mistakenly pushed on the waste gate nipple and bent it. So gently bent it back....but I have a feeling that I broke something inside there and that's where the leak is from? I still have the waste gate from the old turbo if a swap is needed but not sure if bending it would cause something inside to brake(not too familiar with how the waste gate is constructed on the inside)

Thanks once more

ShakesterB6

These cars were notorious for their ignition coils burning out. At a time, it became so bad that I had to carry an extra set in my trunk so that I didn't get stuck on the road. Audi finally issued a recall. I brought my car to the dealer and they did a swap and no problems for the last few years. At any time, have your ignition coils failed and you've just replaced them? If you have, then its a good chance its your cat. After my first few times of the ignition coil fails, my car lost all its power until I got up to higher speeds. When going 55 mph, I would floor it and it would feel great. I take off as I should, but from a stop, I would have to floor it. I had the cat replaced and it was back to normal. Unfortunately, after replacing the cat through Audi with no charge (under 80000 miles at the time), my ignition coils burnt out again. Now at 153000 miles, I'm having the same issues and will replace the cat again. The good news is that I won't have to spend $1600 now since Walker makes a CalCat (California) for $400.00. If you're not in California, you can pick up a Magnaflow for around $300.