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Old 04-02-2010, 05:39 PM   #1
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Ok so i got my car all done and on the road ect, running good with a high idle of about 900 but i was fine with it. The first day of really driving the car during a hard pull (13psi) i let off the throttle and started coasting and my idle was sticking up around 1800 rpm . I have checked over all the vac lines and intake gaskets and all i found was my boost controller was leaking a bit so i removed it and it dropped to about 1650rpm but its still way to high. Where should i be looking for leaks ect? Also since that happened now when im just cruising and let off the throttle and let it coast in gear or down **** my afr's go right to 21.9 So im guessing when i let off the throttle its sucking in a tonne of air from somewhere?? I did a good long log to see if it was in the tune but i'm still having the same problem. Also before and after i did the retune randomly while driving sometimes the car will idle right at 750rpm. Sometimes it stays like that and sometimes it will slowly rise back up after a min or so. I'v been playing with it for 2 days now with no results. Also my vac and 1650-1800 is about 20. Any help or ideas is greatly appreciated. Also would my datalog be any help to anyone?
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Old 04-02-2010, 05:40 PM   #2
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possibly move to tuning section?
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Old 04-02-2010, 05:49 PM   #3
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Do a boost leak test, you'll get your answer quickly.
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Old 04-02-2010, 06:10 PM   #4
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That does not sound like a vac leak really.

Often ECUs will basically provide 0 fuel under a coast-down condition, as there is not really any load. That 21.9 is likely about as lean as your WB02 can read, and I would not worry about it as long as it tends to cycle around stoich (14.7:1) in normal cruising conditions and get right where you want it under decent loads and boost. I am not really familiar with MS, but my guess is that this is exactly whats happening, which is good. I do know that you can adjust this behavior in MS, it was covered in a thread here late last year IIRC.

The idle issue may be a sensor type of deal.

I have yet to find the situation where a pressure test is a bad idea, and you certanly should do one. One thing that still shocks me about this community is the rarity of seeing someone post 'I just did a boost leak test and buttoned her up...'

But I doubt that is your problem. My bet is settings in the MS, a TPS cailbration issue, or something along those lines. The MS forum is you best bet for sure.
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Old 04-02-2010, 07:10 PM   #5
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Are you MAF or MAP based? Also, make sure your throttle cable isn't too tight / sticking.
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Old 04-02-2010, 07:10 PM   #6
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so just test the intake pipes from the turbo to the intake? turbo set-ups are new to me
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Old 04-02-2010, 07:37 PM   #7
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At least you are asking in a post instead of starting a thread just for that question.

Do a search on google for way more info than you need.

A good pic of a home-brew tester like I use is here:

Boost leak test how to with boostpro.net tester - DSM Forums

The pic above "Step 3" shows it.

You pressurize the pipes, as you said, from turbo to cylinder head by use of a little clamp-on device. You really dont need a guage on it since you have a boost guage in the car.

With the pipes pressurized you can listen and feel for leaks. Just be sure you have everything secure. I have nearly lost eyes and other parts of my anatomy this way.

Are you sure you have a 14'G' turbo? The stockers from 1G DSMs are 14B turbos.
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Old 04-02-2010, 07:42 PM   #8
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okay thanks man il deff try it, wow sorry spelling mistake ya 14b
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Old 04-03-2010, 07:18 PM   #9
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well another issue fixed by this forum actually was a vac line coming out of the lower rear intake?? had tape on it from painting the intake manifold guess when i hit 14 it finally had enough and blew off
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Old 04-05-2010, 02:23 PM   #10
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Good to know I was wrong. I love vac leaks. Such easy to fix, so nice when everything behaves properly afterward......
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