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 Post subject: Accelerating slowly causes jerking
PostPosted: Thu Sep 24, 2009 8:36 am 
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Newly Aquired
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Joined: Sun Apr 05, 2009 3:08 pm
Posts: 34
Location: Wisconsin
For the most part my car is runing great. It pulls strong and I am happy with the power. There are a couple kinks that I am trying to work out to make it a more drivable car. If I really stand on the throttle it runs great and pulls strong. When I try to just mildy to moderately accellerate it will sometimes start jerking radically enough that I have to push in the clutch and rev it a few times to get it to settle down then continue. I'm not sure what to adjust to control this behavior. Possibly related to this is run I try to just cruise or sometimes during very slow deceleration it will start jerking as well.


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 Post subject: Re: Accelerating slowly causes jerking
PostPosted: Thu Sep 24, 2009 8:46 am 
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EMI
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Joined: Tue Feb 26, 2008 10:19 am
Posts: 371
Location: Manassas, VA
Sounds like you have a farily large step in your ignition timing table. Take a look at where you would be when the jerking would start (probably 50-70kpa and the RPM where the jerking starts) and you will probably find a jump from 18ish to 35ish. See if you can smooth that out (may be tricky in an 8x8 map without compromise) and that should solve the jerking problem.

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Jon
Project Engineer
Electromotive, Inc
jon at emi.cc
www.distributorless.com


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 Post subject: Re: Accelerating slowly causes jerking
PostPosted: Thu Sep 24, 2009 8:51 am 
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Joined: Sun Apr 05, 2009 3:08 pm
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Location: Wisconsin
Jon, Thanks for the quick response. Is ther a way that I can send you my BIN file to look at? My email is dswalterwi@gmail.com if you want to do it that way.


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 Post subject: Re: Accelerating slowly causes jerking
PostPosted: Fri Sep 25, 2009 11:34 am 
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Joined: Sun Apr 05, 2009 3:08 pm
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Location: Wisconsin
I did a test drive before making changes to see where the map and rpm's were suspect at cruising and found it to be around 34 to 36 MAP and about 2200 - 2500 RPM.
My ignition timing was:
40 - 15 22 25 40 40 40 42 44
30 - 16 20 35 40 40 40 42 44
950 1500 2500 3500 4500 5500 6500 7500

I changed the 35 at 2500 rpm to 30 and that helped smooth it out alot. I also bumped the AFR up a slight bit in the VE tables of the same area.

Thanks for your help,

Running smooth,
Don.


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