3800 L67, can't seem to get rid of KR

[n0dih]

Where I am at right now is I put it in SD mode and it was lean about everywhere (15% or so lean) EXCEPT decel and that was very rich (20-23% rich).

So I am trying to clean that up and see if that is my problem. The problem always rears its head when it goes into PE mode ("OL-Drive" as EFILive says), so if at that point it is dropping over to VE table momentarily, then that explains a whole lot.

The question is isn't GM typically defaulting to rich not lean? The only mod is the gutted air box, which if it does change airflow that much, might explain it.

[Programmer]

Went through your log...where's the KR ?

[n0dih]

Column "F", KR, column "Y" has never ever had any Knock Counts in it. Only my LT1 ever has shown that (OBD1). I don't think B&B, EFILive or MXScan has ever figured out the right memory address to read KC. Does your program? I tried it once, but the demo would not work.

Look at column "F", around row 4667, just at the split second it goes into OL-Drive, it must see voltage on the KS and pulls out timing.

IF I move PE mode TPS vs RPM table up to 80% throttle, the KR moves up there, if i move to 30%, it moves there, if I move to 100%, it moves there.

[Programmer]

Ah....ok. What mods to the vehicle ?
Open air cleaner (under hood) ?

[n0dih]

Just gutted air box, nothing more. Stone stock tune is what is showing all the KR. WOT isn't a problem, it is part throttle/quick stabs at the gas. Like transient fueling is lean. Stock air box had a ton of plastic in it to silence the M90.

Breathing outside air only. Always only at most 10 degrees F over ambient.

[Programmer]

You've even got KR on decel...line 1456-1462

Steady state KR line 3936 - 3959 and decelerating again.

Tip in KR and again through decel line 4534 - 4555

How 'sound' is this engine ? This is starting to look like a mechanical issue.

[n0dih]

Nothing out of the ordinary, would the SC be the culprit? Think a worn blower drive might be part of it?

It only has 91K on it. Well taken care of. You can hear some chatter when cold, or used to, I haven't heard in a while, being this is my first M90 car, I just assumed it was normal sounds.

Maybe not? Think the blower is chattering as it speeds up/down?

But would that track with PE mode moving it up/down?

[Programmer]

This may sound weird, but anything loose ? Brackets ? Motormount ? Exhaust ? Torque converter coming apart ? Anything audible ?

[n0dih]

Nothing loose that is obvious, I have run with/without engine cover, just had fuel rails off, nothing loose there, PCM isn't held down like factory in air box, I got a little carried away with the sawzall. I will check it and tighten up. When I was under doing oil change last time, nothing stood out.

No odd audible noises, converter has no bad feel.

I even ran with E85 at one point and I did bring timing up some, but still had KR show up. That is what gets me, octane doesn't seem to have much effect. But running the PE mode up is a serious drop in power, so I know I am getting the fuel.

With a gutted airbox do I need more "pump shot"? I can't imagine it makes THAT much difference would it?

Originally Posted by Programmer

This may sound weird, but anything loose ? Brackets ? Motormount ? Exhaust ? Torque converter coming apart ? Anything audible ?

[Programmer]

You've gotta ask the question...why KR, no load--decel. That's telling me something...