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Cold stumble/stutter off idle

tsitalon1

Well-known member
Joined
Dec 29, 2010
Messages
309
Location
Montgomery Al
Hey guys,

I'm hoping you can help isolate a driveability issue for me.

For some time now, I've has this stumble right off idle as I'm just getting on the throttle. It only occurs while the motor is cold.

I've attached a log with two captured events.

This issue has persisted through tuning changes and different injectors.

MAF is a 399 model with honeycomb in place, and BOV is a stock crushed unit still configured to recirculate. I've checked for boost leaks up to 25psi and cannot find any. Throttle body has the FIAV block off but functional ISC. Trims are within 3% normally.

Log file:
Here
 

ktmrider

Well-known member
Joined
Sep 10, 2007
Messages
3,128
Location
Tempe, AZ
FWIW I can't view the log.

Should have something to do with Open Loop operation ( OL when cold, Closed Loop at operating temps ) and/or Cold Enrichment.

For the most part it's use of the O2 sensor, what are the O2 readings when cold? What is the ECU temp reading?

I had a similar issue with 86/2000, replacing the PCV ( OEM only, no Framinator crap ) and ensuring all manifold related seals were good solved it.
 

tsitalon1

Well-known member
Joined
Dec 29, 2010
Messages
309
Location
Montgomery Al
Mike, are you using DSMlink to open the log? Let me know if you can't open it with DSMlink.

I ask because I know it was working on the dsmlink forums...I'll re-upload if neccessary.
 

ktmrider

Well-known member
Joined
Sep 10, 2007
Messages
3,128
Location
Tempe, AZ
No I don't have 'Link is the reason.

Screen cap the graph/chart for those of us non-linky folks.
 

ktmrider

Well-known member
Joined
Sep 10, 2007
Messages
3,128
Location
Tempe, AZ
Thanks! Some like me are still on Keydiver chips and pocket loggers.

TPS Throttle Position % is way high ( 22% ), should be 9-11 when the throttle is closed. First thing I'd adjust.
 
Last edited:

tsitalon1

Well-known member
Joined
Dec 29, 2010
Messages
309
Location
Montgomery Al
I think you misunderstand...

It's at 22% because that's the point in which I stepped on the throttle. All those figures are at the exact point shown by the white vertical line.
 

prove_it

Well-known member
Joined
Jul 3, 2008
Messages
4,201
Location
Sioux Falls, SD
Whats your fuel ratio? I see no log of fuel ratio.
 
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