Update on 4 psi and almost stalling problem...

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Mar 30, 2006 | 01:07 PM

SpyderSE2(movie man)

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Update on 4 psi and almost stalling problem...

So after working for awhile today on my sisters 98 A4 Tip, I seemed to have fixed the idle problem with the car no longer almost stalling. Now I am even more baffled about the low boost problem though. I thought they would have had something to do with each other but it seems they are seperate problems as the car still only boosts 4psi. Car runs fine it just doesnt build boost past 4 psi. Here is a list of things I have tried-
Replaced KO3 turbo
Replaced MAF sensor
Replaced N75
Replaced BPV
Pressure tested system with DIY pressure test, fixed on leak, didnt solve problem.
Recoded GIAC chipped ECU to different code which fixed bouncing idle.
-Other info
Boost gauge reads ~19 In. Hg at idle and under WOT hits 3psi in first and 4psi in second.
No DTCs or CELS.

-What I think it could be-
Only thing I think it could be at this point is perhaps a clogged Cat. Before I unbolt it does anyone else have any ideas? Is there anyway this could be related to PCV system?

Mar 30, 2006 | 01:10 PM

illbill

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From: Cambridge, MA

How's your T28 running, get all your MAF issues straightened out?

Mar 30, 2006 | 01:14 PM

SpyderSE2(movie man)

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My T28 is running really strong now...

I picked up a Mk3 VR6 MAF housing for it. Boosting up to around 19psi now, its a blast to drive. It was amazing how much the stock MAF housing was bottlenecking the whole system.

Mar 30, 2006 | 01:29 PM

illbill

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From: Cambridge, MA

I'm sure you were running rich as hell because the ECU was seeing erroneous high maf readings

If you have the chance you should log and submit a CAPS times. There is one other T28 tip to compare with at this point. I'm sure that he would be happy to see another person with a similar setup to him.<ul><li><a href="http://www.modifieda4.com/web/caps/b518-new.html">B5 1.8t CAPS Databse</a></li></ul>

Mar 30, 2006 | 01:33 PM

SpyderSE2(movie man)

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Yea it was...

I was getting system too lean codes after like 30min of driving. My car is a manual so it wont be able to compare to that one on the CAPS but I will log my car anyway and add it in soon.

Mar 30, 2006 | 01:43 PM

BJC::wokka wokka

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Lets see some CAPS times!! : P

Mar 30, 2006 | 04:49 PM

ImAwesome

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that sounds similar to the limping i had to get my car home under...

for me it was the big hose that plugs into the DV valve. it popped off. Reclamped and it started to work... next issue was it was still boosting low... ran a vag and noticed bad oil sensor. Well i just sea foamed earlier and thought it might have gummed it up. Drained all the oil.. pulled sensor off .. cleaned it using rubbing alcohol.. put back in and it was no longer getting the error. My boost came back to... now the reason why. If any of your systems aren't working correctly.. i.e. oil.. coolant.. the ecu limits boost. FROM WHAT I UNDERSTAND... so if you have a vag... scan and see if any issues come up.. i know your in socal somewhere and if you need a vag i'd be willing to help