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EFI - Vent learn ????????????

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Old Sep 5, 2001 | 12:57 PM
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rx7tturbo's Avatar
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EFI - Vent learn ????????????

Do anyone know what you can do so that the boost is at exactly what you set it to be?

For example: Data set 1 is set with PRI @ 10 PSI and SEC @ 11 PSI. Now it's pretty much dead on the boost most of the time but then once in a while it would go up to 12, 13 PSI.

Data set 2: PRI @ 12, SEC @ 13, now this almost go up to 14 or even 15 most of the time.

Should vent learn be turn off??? I've heard no, it's not a good idea but then how do you really effectively control boost with EFI?

Thank you.
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Old Sep 6, 2001 | 09:03 PM
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From: Ponce PR
how do you really effectively control boost with EFI?
Get an electronic boost controller ...

The vent learn feature is like the fuzzy logic on the AVC-r and the EVC. After time it should "learn" the boost curves on your car. For a while i tried the vent learn thing, then I just switched it off and put some "target" values in manually. Afterwards, I bought a boost controller.

BTW, did you leave the pills inside the hoses that lead to the wastegate and turbo precontrol actuators?
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Old Sep 7, 2001 | 02:41 PM
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Yes, I left the stock pills in there.

Fuzzy logic, that I know...it would be nice if boost is really locked at the setting you set it to be. I don't know why EFI does not have something in place so that it limit/lock the boost.
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Old Sep 8, 2001 | 04:30 AM
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What are your intake/exhaust mods? You could be experiencing boost creep if you have it all opened up and get this behavior more often in higher gears.

The older EFI units (but still the purple ones) used to have a problem that boost would rise if you left vent lean on. However, that was fixed with the April 99 software, so you should be able to leave vent learn on if your software is more recent than that.
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Old Sep 10, 2001 | 11:32 AM
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Mine is the newer one...bought it in April of 2000. Straight through exhaust. (DP/MP)

I think this is the problem but just wondering if there are any tricks or methods on effectively controlling boost...
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Old Sep 22, 2001 | 02:57 PM
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If you've got the newer EFI software, you should be fine leaving vent-learn on. If you leave it off and manually enter values, you'll have to control/compensate for colder and warmer weather. My PMS seems pretty responsive in controlling spikes (brought about by sudden change towards cold weather, for example). Check out Wade Lanham's site for a good discussion of vent learn:

http://www.wvinter.net/~flanham/wlanham/
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