hard jerk/hesitation tuning issue
 

i noticed after i had my car tuned that when i get into boost, and slowly let off the throttle, and get back into primary only injection (2 psi), my car does a real hard jerk/hesistation. What do i need to do to tune this out? I believe it has something to do with the injection staging. I read the sticky and still am a little confused as to why this would happen.

what injectors do you have?

What ECU do you have.

thewird

bosch 850cc primaries, and 1600cc secondaries. It's a microtech LT-10S i believe (does both fuel and ignition)

Does the jerk occur when you are in decel fuel cut and then get back on the throttle?

Not tuned very well.

Try to Recab your TPS.

Its not your TPS.

How so? i had this problem before and after recabing the TPS it worked.

to rich at 0 hg and 2 psi ?

You had a different problem.

he has a staging problem. very common.

so how do i fix it?

Well, the short answer is to adjust your staging settings.

With 850CC primary and 1600CC secondary, try 90% for %stage.

Then stage at 3500RPM and 2" of vacuum.

i had 50 % and stage at 1750 and 0 hg and it seemed to help a bit

I have played alot with staging and found that the Opt_mapstg % has made 0 difference in most scenarios.

I leave them on 50% and tune out the miss.

well, my staging is tuned at 98% i believe. My car has been in the body shop for a while and i can't remember, but dave at KDR set it up for me, then he and i tuned it with the "base" settings that he normally puts into every car. If i reset my staging to 90%, i do have to re-tune the entire MAP after the secondaries come on, correct?

No you have to retune your whole map before the secondaries come on.