Numerous Acceleration Problems

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Mar 12, 2020 | 06:15 AM

Paul White

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Numerous Acceleration Problems

Hey guys, looking for some possible resolution to a number of problems I am experiencing with acceleration.

Firstly, car and any mod details;

2002 Audi TT Mk1 8n
103k miles
RAM air intake
APR stage 1 MAP
Decat pipes
Forge splitter valve
manual boost controller
mechanical boost guage

The issue I am having is very irregular acceleration problems, such as;

jerky in the low revs before boost comes on
intermittent boost loss in all gears, no pattern to this

so for example, WOT, the boost will spool up to 1.5bar no problem and the car pulls nice and hard, and then all of a sudden, ill go for full acceleration again and it jerks a load, and then only spools up to 0.5bar.

ive just replaced the MAF, and the N75 valve hoping these two might be the cause, but today when test driving, no change whatsoever.

I am really losing the love for the car now because I cannot figure out what is causing this. Sometimes, it doesn't happen at all and drives perfectly, and then out of nowhere, all these problems start happening.

any advice on my set up, good or bad criticism is very welcome, I just want my nice performing car back

cheers in advance,

paul

Mar 12, 2020 | 05:59 PM

Mister Bally

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From: Las Vegas, Nevada USA

Massive air leak between the air intake system and intercooler(s).

Mar 13, 2020 | 12:25 AM

Paul White

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many thanks for the response.

I have a FMIC install on the TT. I cant hear any leaks, and would have thought that if I had a leak, the issue would be present at all times?

Mar 13, 2020 | 02:00 AM

Paul White

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update.

yesterday after I ran VCDS I had no codes (other than O2 sensors as I have decat pipes) but today, all manner of errors;

P0130 N249 VALVE MECHANICAL MALFUNCTION

(get a stock 710p 710n DIVERTER VALVE)

P1555 MAXIMUM BOOST PRESSURE EXCEEDED, INTERMITTENT

P1296 ERROR IN MAPPED COOLING SYSTEM

P1602 POWER SUPPLY B+ TERMINAL VOLTAGE TOO LOW

P0103 MASS AIR FLOW SIGNAL TOO HIGH

P1548 BOOST PRESSURE CONTROL VALVE (N75) OPEN CIRCUIT

01435 - BRAKE PRESSURE SENSOR 1 IMPLAUSIBLE SIGNAL

01314 ENGINE CONTROL MODULE NO COMMUNICATIONS

I have changed out the MAF and N75 so these may not return after I test drive this am but the others....

Mar 13, 2020 | 06:46 PM

Mister Bally

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Joined: Jan 2006

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From: Las Vegas, Nevada USA

I'd be looking for a tear in a rubber boot/coupling on the pipes between the turbo, intercooler, air filter and intake manifold.

Jun 22, 2020 | 06:18 AM

Paul White

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just to respond to this, I have opened another chat elsewhere on the site.

I ran a pressure test through the intake and no leaks detected - it held pressure fine.

Still still chasing this PITA issue

Jul 10, 2020 | 09:22 PM

Breyden Phillips

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Joined: Apr 2020

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From: North Carolina

I agree with bally is sounds like a major boost leak. Mine was doing the same thing right after I installed a FMIC. Does it only do it after hitting full boost or does it do it from the very beginning? I would also tell you to do the N249 delete. It will make your acceleration better (it does for cars that are running right). The N249 will release boost at random times and it may be something to look into.