Tony Hoffman-4000Q

Hi all,

I am having an issue with an A4 1.8T that I'm unfamiliar with. It is overboosting, and causing a code of 17963 - P1555: Charge pressure:Maximum limit Exceeded. I see a max of about 13-14PSI before it throws the code and goes into a "limp" mode of sorts. After that, It won't allow anything more than about 1-2 PSI. If I clear the codes, I get a 13-14 PSI run every time, then shutdown. It shuts down immediately after hitting boost, even with the throttle still floored.

Background of the car: It came into the shop with a blown engine(hole in the oil pan) and we swapped it. I ended puting an APH engine into it, but put the variable cam tensioner into it as well. It also has a new turbo on it. I don't know about the turbo wastgate adjustment, but it was positioned the same as the old one, by my measurement. The thing that has me leading away from that is the fact that it can reduce pressure with no problem after going into the limp mode. BTW, all boost measurements are via a manual boost guage I have T'd into the intake.

Thanks in advance,
Tony

TwentyValveB5+S4

I'd log block 115 to see the N75 DC.

Check your DV and the vac. lines. Also make sure you didn't introduce a leak where the boost gauge tap was done.

@wesome

what you're seeing

Tony Hoffman-4000Q

Automatic, and I forgot to mention I used everything but the block and head from the A4. So, it's all back together as if it were an AWM.

Tony

Tony Hoffman-4000Q

I did check it already. However, I'll check it for sure tomorrow morning. Thanks.

@wesome

could also be a faulty MAP sensor then

pentosinjunky

If so, the TT225 motor...budget forged internals built?

Tony Hoffman-4000Q

With enough time, patience, and money. I had to modify the A/C bracket slightly. I also had to build a new bracked to support the turbo on the side, as the factory one uses a Boss that's not even cast into the transverse engines.

Trust me, I went through hell to even get this engine. First, I paid "Specialized German" in CA for an AWM, which they sent me. Well, sort of. They said it was, but had ground notht the codes off it and painted the block so I wouldn't be able to tell. Except, I'm no idiot, and when I saw "Mexico" on the back it was a very glaring clue. Anyhow, they sent another, true AWM, but it took two weeks, and by then I had already got this engine locally with 65K on it. So, I went with it.

I used all the AWM stuff, including the TB gears, so aside from the engine code, it's hard to know it's not stock. Oh, and it's got 9.5 to 1 instead of 9.3. So, it's a slight upgrade (180hp when used with variable timing). I mostly used it because I'd already had the car torn down for a month, and didn't want the customer paying for a rental any more than necessary.

As for the TT engine, I'd thought of that. However, there are other things that would have to be upgraded like the injectors. This one wasn't enough to upset anything electronic related.

Tony

Tony Hoffman-4000Q

The boost problem is fixed. I checked the boost hoses going to the N75 boost control solonoid as suggested. They were fine. However, while in there I noticed junk in the N75 itself. Not sure when it got in there, as I never had any of that apart. But, whatever, it's fixed. Holds 7-8PSI normal spirited driving, up to 10 in first gear.

However, I have a much more severe problem. Although the solution is on the way. Yesterday, while working on the boost issue, I noticed that it started smoking a LOT upon startup and while running. I was thinking"huh, that's wierd", but wanted to concentrate on the boost issue first. Today, when I got it cured, I took the car for a drive. We have a 4-mile loop that we use. Well, the car was running great, other than smoking like crazy. So, I thought, one issue fixed, one other to fix, and the car will finally be back in it's rightful owners' hands. Yea, right!!

I was leaning toward a crankase vent problem, but hadn't got back to the shop yet to troubleshoot. Out of the last turn (right, after a stoplight), step down on it, 10psi in first, into second, 0psi. WHAT!! Ok, I think there was a noise also. Maybe I forgot to tighten a hose clamp somewhere. (wishful thinking) NOPE. Strange noises at idle, hmmm. Back in the shop with my stethescope, the new turbo is making all that noise. Pull the loser intercooler hose and oil poured out of it!!Noooooooooooooooo......... this car will never leave!! Well, the turbo is warranteed, so a new one is on it's way. But, of course, I get to eat the labor. It was much easier when the engine wasn't installed Oh well, onto the next car............


Again, thanks to those who pointed me in the right direction,
Tony Hoffman