I've been wondering this for a while now... Does the IAM really matter after you have engine management? More specifically a UTEC?

With most EM (reflashes of any kind, any true piggy-back), yes, it still matters. With a UTEC, it only matters below the crossover point. Above the crossover point (by default, 25% with Open Loop Fueling enabled), the UTEC runs static timing based on your map. The IAM doesn't matter.

With a UTEC, the IAM is still an indication of how "happy" your ECU is with your current state of tune. Even though the UTEC is controlling timing after the TPS crossover, the ECU is still listening to what is going on. If it doesn't like what it is hearing, the ECU will try (in vain) to yank timing. Once this happens a few times, the IAM starts to drop.


How much does this apply on the really big (500-ish) HP setups? I don't know.

Are things really "unsafe" if the ECU isn't happy? I'm not certain. I know that I don't like it. ;)

If the IAM is dropping with a Utec then you need to get a tune.. The ECU is seeing knock.

Clark

If the IAM is dropping with a Utec then you need to get a tune.. The ECU is seeing knock.

ClarkWhat if the motor is just "noisy"?

A 2004 STi w/ replacement pistons has just been dropped in my lap with a IAM of ZERO. :huh:
The *highest* knock correction value I saw while logging was ONE. :huh:
Under WOT, the knock correction dropped down to -11.5. :eek:

This car is in some serious pain. :lol: I'm hoping I can breathe some life into it.

What if the motor is just "noisy"?

A 2004 STi w/ replacement pistons has just been dropped in my lap with a IAM of ZERO. :huh:
The *highest* knock correction value I saw while logging was ONE. :huh:
Under WOT, the knock correction dropped down to -11.5. :eek:

This car is in some serious pain. :lol: I'm hoping I can breathe some life into it.

There has to be something really wrong with the car. I have the loudest forged piston engine in new englend (I think). The lowwest KC I have seen is -4 when the engine was cold. I see +11 on a routine basis.
Just $0.02 to think about.

TMS

There has to be something really wrong with the car. I have the loudest forged piston engine in new englend (I think). The lowwest KC I have seen is -4 when the engine was cold. I see +11 on a routine basis.
Just $0.02 to think about.

TMSTrust me, I've been thinking about it! ;)

From what I know, it's been driven around on an untuned UTEC map while overboosting on pump gas (25+psi and VERY likely knocking). Last I *heard*, a compression test returned good results. If I start to doubt things, I'll do my own compression test.

Today: the ECU gets reset, the wideband goes in, the UTEC OLF injector numbers will be scrutinized/adjusted, and a decent base map goes in.

Trust me, I've been thinking about it! ;)

From what I know, it's been driven around on an untuned UTEC map while overboosting on pump gas (25+psi and VERY likely knocking). Last I *heard*, a compression test returned good results. If I start to doubt things, I'll do my own compression test.

Today: the ECU gets reset, the wideband goes in, the UTEC OLF injector numbers will be scrutinized/adjusted, and a decent base map goes in.

One of the local guys here had almost the same thing. What it ended up being was a bad knock sensor. The tech that put the motor together way over tightened the sensor. It should only have 17ft/lbs on it and it took a breaker bar to remove the old one. Replaced the sensor and the car is much happier.

TMS

One of the local guys here had almost the same thing. What it ended up being was a bad knock sensor. The tech that put the motor together way over tightened the sensor. It should only have 17ft/lbs on it and it took a breaker bar to remove the old one. Replaced the sensor and the car is much happier.Thanks for the tip!

We'll see how things pan out... :)

One of the local guys here had almost the same thing. What it ended up being was a bad knock sensor. The tech that put the motor together way over tightened the sensor. It should only have 17ft/lbs on it and it took a breaker bar to remove the old one. Replaced the sensor and the car is much happier.

TMS


So was the knock sensor indicating knock randomly when there was none to detect. Was it also showing mis-fires?

I think I may have the same problem. I tightened the knock sensor out of haste trying to get the 2.5 motor finished up. I later thought about it and loosened it and re-torque to 17ft/lbs. It was on tight when I tried getting it off. I had to take the knock sensitivity values down in UTEC (granted it's a WRX UTEC with more sensitive values than the one for the STI 2.5). I'm now mostly just getting mis-fires with new plugs (BKR8EIX @ .030) and that's below 4.5k rpms with with little boost (like 10psi) and occasional knock through UTEC. AFR has been monitored and set to 4.5k rpms as well as timing which I've played a lot with to no avail.

So was the knock sensor indicating knock randomly when there was none to detect. Was it also showing mis-fires?

I think I may have the same problem. I tightened the knock sensor out of haste trying to get the 2.5 motor finished up. I later thought about it and loosened it and re-torque to 17ft/lbs. It was on tight when I tried getting it off. I had to take the knock sensitivity values down in UTEC (granted it's a WRX UTEC with more sensitive values than the one for the STI 2.5). I'm now mostly just getting mis-fires with new plugs (BKR8EIX @ .030) and that's below 4.5k rpms with with little boost (like 10psi) and occasional knock through UTEC. AFR has been monitored and set to 4.5k rpms as well as timing which I've played a lot with to no avail.

Yes the knock sensor was showing random knock events. No mis fire codes, no codes at all.

TMS

Damn, I wonder if I should put the $70 down for a new sensor then? I am getting frequent mis-fires as well as the knock events.