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Car "stumbles" at lower rpms

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Old 01-30-2008 | 04:18 PM
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90turboMX5's Avatar
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Default Car "stumbles" at lower rpms

Ok, I finally got my car running decent. LC1 reads fine, yeaa!!!. I do have a problem and it is that at lower rpms (1000-3000rpms) when I'm cruising and apply throttle the car stumbles, its not smooth at all. I did many logs and used the analizer but I cant get rid of it. Could it be a timing issue or VE table is not adjusted right??
Any ideas?
BTW the car does have a 7lbs flywheel but I dont belive it makes such drastic driveability issues. Im sure its the tune, but I dont know where to look.
here is my (well, brainecks tune modified to suit my car) tune
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Old 01-30-2008 | 04:35 PM
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did i give you that fuel table?

how rich are you? from glancing at the msq it looks like too much fuel.

post a log as well, that would be more helpful. Try turning off the CLT-related air density correction....go to advanced and turn it to normal....
Old 01-30-2008 | 04:47 PM
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90turboMX5's Avatar
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Originally Posted by Braineack
did i give you that fuel table?

how rich are you? from glancing at the msq it looks like too much fuel.

post a log as well, that would be more helpful. Try turning off the CLT-related air density correction....go to advanced and turn it to normal....
Yea, you posted that fuel table but I modified quite a bit.
Here is a log and here is my other map that I smoothed out by hand after analizing the 1st map (the one I posted) through the log.
I didnt have time to try it yet but it should make it better.
Cruising AFR is 14-16 it jumps all over.
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2nd test.zip (286.1 KB, 40 views)
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Old 01-30-2008 | 05:23 PM
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everything looks fine, to me it looks rich in cruise. 11.5-12:1.

I see a few times on the log where it freaks out. like you blipped the throttle over and over.

I see the MAP go to 80 and then to 12 and back up and down....is this when you are having the issue? 5343sec on the log. 2nd test.
Old 01-30-2008 | 09:37 PM
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Is AE kicking in during cruise? If the MapDot/TpsDot threshold is too low, or if there is noise in the signal, you can have AE kick in when you don't want it and make AFR wildly jump around...

If it's just happening at tip-in it could be AE just needs to be dialed in.

Otherwise it may just need a good steady state tune... I've felt cars run like CRAP that just needed a good tune, and people had been driving them that way for a while and dealing with it. Tune it and a beautiful thing happens .
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