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Possible Causes Of +25 LTRIMs?

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Old 08-11-2004, 04:59 PM
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Default Possible Causes Of +25 LTRIMs?

First of all, I haven't seen this car, but I'm looking at a HPTuners log file of a car located several states away from me and the LTRIMs seem to be pegged at +25 except for a very small part of the log where they drop to maybe +17. They are at +25 for 90% of the log. O2s seem to be switching OK and go to around .930 at WOT. I could email the log to someone if they want to take a look at it. It's a 98 A4 and I'm told the mods on the car are:

SY3500 stall TC
Mildly Ported and Polished heads
Lunati 221/221 558/558 lift @ .050 114 LSA
Harland Sharp 1.8 RR's
Ported and Polished TB
SLP lid
March underdrive pulley
Jet hot LT's with EGR deleted
Air pump deleted

I'm told the MAF is unported and still has the screen.
Old 08-11-2004, 05:38 PM
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Intake has a leak........
Old 08-12-2004, 06:58 AM
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Or the exhaust does. It happened to me and had the same symptoms. Fixed the leak and LTrims came down to where they should be.
Old 08-12-2004, 05:44 PM
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From what I have seen, when you let off the gas your Ltrims will go way up if you have a exhaust leak.
Old 08-12-2004, 08:41 PM
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Originally Posted by Scooter70
Or the exhaust does. It happened to me and had the same symptoms. Fixed the leak and LTrims came down to where they should be.

I've been having the same problem. My Ltrims would be 25 at idle. Once I get on it they drop down. I do have an exhaust leak though. It's hard for me to understand how an exhaust leak can affect ltrims. Anyone care to explain?
Old 08-12-2004, 08:47 PM
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have you checked fuel pressure? and i would check to see if the injector flow rate table has been messed with.


and on your exhaust leak causing a lean effect, is because the leak will suck in fresh air into the pipe, and that fresh air goes past the o2 sensor, which measures oxygen, which is now being introduced into the pipe, so it thinks it is running lean. and will keep adding fuel untill it cant anymore,
Old 08-12-2004, 09:21 PM
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and on your exhaust leak causing a lean effect, is because the leak will suck in fresh air into the pipe, and that fresh air goes past the o2 sensor, which measures oxygen, which is now being introduced into the pipe, so it thinks it is running lean. and will keep adding fuel untill it cant anymore,[/QUOTE]


ooooooooooooooooohhhhhh. Thanks man. another small question. should the ifr table increase as the manifold vacuum decreases. Like the stock one. I'm not using boost reference on my fpr.




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