turb

i've searched and can't find any answers.

here's the setup:

00' SiR (00' Si but with 4 doors)
b16a using a smallish nissan t3 turbo boosting .54bar or about 7.8psi
dsm blue top 450cc injectors
JDM P08 ECU street tuned with uberdata 1.7 using FJO wideband and Knock LINK
stock internals
stock TB, IM and flywheel.
Exedy Organic clutch disc and Exedy pressure plate
stock fuel pump


ok here's the problem, after street tuning for a few hours and car running great the engine stalls on decel. it only happens when i hit FULL BOOST and when i engaged the clutch to shift to neutral when decelerating and coming to a stop. i've checked for vacuum leaks and cleaned my IACV. replaced my TB gasket already, even swapped MAP sensors from a similar engine and it doesn't seem to help.

there is NO check engine light and car runs great with or without boost. sometimes i quickly shift to neutral when decelerating and it would not die on me immediately but after hesitating for a few seconds it stalls. the wideband would register a lean condition when it's hesistating before it stalls. the tach just dives down and engine stalls. is this because the ECU cuts the injectors when decelerating?

after starting the engine back again, it runs great.

Does not stall on idle like some people experience, only when decelerating and engaging the clutch when coming to a stop after FULL BOOST.

didn't have this problem when i was using the hack.

only happend when i switched to uberdata 1.7 and when we were almost done tuning the car on the streets. incidentally when this started happening the engine temps would rise to 3/4 on the temp gauge and the radiator fan would not turn on, turn out to be a bad thermoswitch so replaced it and never had a problem with engine temps again so i don't think that problem was related to the stalling. i have my idle set at 900rpm. i'm suspecting a bad TPS..will a bad tps cause the engine to stall when decelerating after FULL BOOST? it only happens after FULL BOOST.

This never happens on friend's cars running uberdata 1.7 and boosting.

this problem is driving me nuts! hope someone can help me..

BoostedCivicSedan

Theres a setting in Uberdata you have to change, although I dont remember right off what it is... Im assuming you leave it in gear to decel, which from a higher RPM, causes the motor to see excessive vacuum, to the point it is too much vac. for the map to see, which causes the CEL and the car just shuts off... Mine does it too

hondaguyef

The setting you need to adjust is "fuel cut value" in the boost tab. If you have a 3 bar set it at 7-8 if you have a OE map set it at 12. It just raises the amount (In/hg) of vacum the MAP can see from like 24.xx up to 28.xx depending on how low of a number you use. Good luck.

Phil

turb

ok, i've checked my bin file and fuel cut value was set at 24. i will try to set it at 12 and see what happens. i'm using the stock MAP sensor. thank you very much..i hope this solves my stalling problem.

boostedcivicsedan,

are you referring to the fuel cut value which hondaguyef is referring to? yes i'm decelerating in gear and when i shift to neutral to come to a stop the engine stalls but no CEL whatsoever. sometimes i quickly shift to nuetral when starting to decelerate and it doesn't stall immediately but hesitates for a few seconds and eventually stalls.

i will try to set the fuel cut value at 12 and hope it solve the problem. thanks for you input.

hondaguyef

If setting it to 12 deosn't work just keep going lower. The lower the number the more in/hg the MAP sensor can see. 12 should do the trick though.

dustin

I had this same problem w/ uberdata. Boosting or long highway drives (10+mins) clutching in would make the car immediately stall. It's something with uberdata... because the only way I was able to fix it was by upping the idle speed to 950-1000rpm. The ECU is unable to catch the falling revs fast enough during decel fuel cutoff (no check engine lights either.. the car just stalls). My final solution to this problem involved Hondata