ITB Tip-in(?) problem

s300 and SManager software questions & answers
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Jim_H
Posts: 26
Joined: Mon Oct 31, 2011 1:22 pm

ITB Tip-in(?) problem

Post by Jim_H »

Hi!
Tuned a Civic EG TWM ITB's the other day. At WOT and low load over 2500 rpm it is good. But under 2500 rpm (opening the throttle slowly) the car goes very lean and hesitates. It is tuned using alpha-n and but still has a map sensor. We also had problems with big hesitation / fuel cutoff when changing gears at WOT. I have tried everything I can think of regarding tip-in and fuel cutoff but it doesn't seem to make a difference. in fact, I can't see anything changing at all and I have gone completely stuck. Of course tried to both upload several times and turning the key off.
Here is the full spec:

B20 bottom 12,5 cr
B18 head with Skunk 2 Pro 3 cams
Precision 650cc injectors
E85 fuel
TWM ITB's
Hytech header / 2,5" exhaust

I will attach cal and datalog files with the problems. I would be very thankful if you could give me some guidance on how to approach this problem.
I tried everything from 256-800 in tip-in fuel but it doesn't seem to make a difference. Perhaps I have forgot some critical setting?
One log is WOT and the other one is low throttle openings. Going very lean at tip-in (?) it seems like, changing the fuel tables at those areas do not help much.

Thank you very much for your time.

/ Jim
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Spunkster
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Joined: Fri Sep 20, 2002 5:06 pm
Location: Hondata

Re: ITB Tip-in(?) problem

Post by Spunkster »

Do you have a vacuum accumulator to help with the MAP sensor reading and seeing vacuum?
Jim_H
Posts: 26
Joined: Mon Oct 31, 2011 1:22 pm

Re: ITB Tip-in(?) problem

Post by Jim_H »

Yes. The customer routed vacuum lines from each runner that goes to a canister where the map sensor also is located.
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Spunkster
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Posts: 23878
Joined: Fri Sep 20, 2002 5:06 pm
Location: Hondata

Re: ITB Tip-in(?) problem

Post by Spunkster »

The overrun cutoff % values look really high. You should try a value closer to 0.
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