1CAMWNDR

iTrader: (21)

Here is the deal:
In 1600 and 2000 rpm colums only, at less than 15% throttle only I get an annoying lean spike every 5.5 seconds. Any gear, any road speed. Every 5.5 seconds. I have OLSD tune so there is no MAF to worry about, nor stock O2s failing. It feels like the car hits a rev-limiter for one instant, spikes lean and then goes a bit rich and then settles back in line. For 5.5 seconds. Sure makes cruising around corners interesting with the Locker.
What the Hell is that? I can find nothing in the fuel control that happens at less than 15% throttle or every 5.5 seconds.
The only thing that happens is the spark advance drops to almost 0 every time it happened.

RedHardSupra

iTrader: (1)

got logs?

jimmyblue

iTrader: (11)

Spark and fuel cut together is the signature of DFCO.
Maybe the car gets enough of a whiff of "deceleration"
to kick that in. Try disabling DFCO entirely and see if it
quits the behavior. If so then the next question is,
what accounts for triggering it rhythmically?

1CAMWNDR

iTrader: (21)

Yes I have a log.... I will try to post it in a moment.

1CAMWNDR

iTrader: (21)

Damn I hate being on-call. Now then, the Log:

1CAMWNDR

iTrader: (21)

I was wondering about the DFCO also, but can't understand it going into DFCO every 5.5-6 seconds. Good idea to just disable it and see what happens.....

1CAMWNDR

iTrader: (21)

OK. Disabled DFCO and the problem has fanished. I reset the entry TP% up to 20% instead of the 15% it was at. We will see if that fixes the cruise lean spike/stumble. I think it should.

Billf6531

I think you may want to try 10% instead of 15% to avoid triggering DFCO at light throttle.

1CAMWNDR

iTrader: (21)

It is better, but I agree that 10% should work better. It rarely goes down to 10% with the cruise control on. Now I just need to get the kPa fixed so it still works at cruise so I can save more gas.

cosmo vyss

This exactly I think as to whats been happening in my car. Did the changes you made fix it. What was the final result of this?

JB

2002_Z28_Six_Speed

iTrader: (19)

Why do you have your DFCO throttle setting so high?

You should be able to lower it back again if you play with your MAP, RPM, and VSS settings. I have mine to come in [way] under about 5% and it never comes on when I don't want it to.

cosmo vyss

Did you enup sorting out your problem? I think it may even be fuel injector problem. Well thats where I am going to test next on mine.

JB