Weird hesitation, A/F goes lean and then back to normal

K-Series Programmable ECU installation questions / support issues
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mdoyle
Posts: 24
Joined: Wed Apr 06, 2005 12:53 pm

Weird hesitation, A/F goes lean and then back to normal

Post by mdoyle »

Over the last week i've started to get a problem where when cruising on the freeway my car gets this weird hesitation. It feels like the RPM was bouncing, even though I was maintaining a constant speed. I did some datalogging and found out that my A/F ratio seems to spike lean then come back to normal causing this jerky-ness. I am using the same calibration I have for a long time, no new mods, nothing has changed. At first I thought it was the weather, as it is starting to get hot here in Az, but that's not the case, as this morning I had IAT at 80F and it did it again.

Datalog is attached if anyone has any suggestions.
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chunky
Posts: 50
Joined: Wed Mar 09, 2005 9:41 pm
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Post by chunky »

where's the datalog?

definitely sounds like you're hitting the lean cut.

*edit*

n/m, there/s the DL
You can take me out of the race, but you can't take the race out of me.
chunky
Posts: 50
Joined: Wed Mar 09, 2005 9:41 pm
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Post by chunky »

everything looks okay, your k count is 349?!?

I see only one lean spike in there. Doesn't look like the lean cut was engaged there though.

Try to change the lean cut so that it only engages at high engine loads.
You can take me out of the race, but you can't take the race out of me.
mdoyle
Posts: 24
Joined: Wed Apr 06, 2005 12:53 pm

Post by mdoyle »

Lean Protection isn't even enabled right now.

I noticed that knock count as well, but if you look throughout that datalog, no knocks occured during that time. So I don't know, does the ECU remember knocks? All my knocks happen down low in the RPM range, no matter how much ignition had been pulled from those areas it still knocked, so we figured it to be the "phantom" knock some K series cars seem to get.
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