Hondata

setup:

rc 550cc injectors
resistor box
stock fuel rail
walbro 255hp pump
fpr set to 50psi @ 1 bar
purge valve disconnected
aem wbo2 w/methods mod



problem:

i've been tuning my car and for some reason everything above 600mb is lean and have to add quite of bit just to get it on the rich side. romeditor is showing me at almost 54% dc and i'm not in vtec. my multiplier is set to .436. everything below 600mb is rather rich and can come down some. which i have. but for some reason and only when i cross 600mb the car drops lean, even if i do it slow and keep it around 600mb it will drop lean and then come back up?

any suggestions?

Try using a stock FPR at the stock pressure. Static fuel pressure should be measured at idle with the vac line disconnected from the FPR.

i don't have a stock fpr. last time i used one, i had almost 60 psi and i wasn't able to adjust it nor would it move as i would move in and out of vac. fuel pressure stated above was measured at idle with the line disconnected. my use for reference atmospheric pressure=1 bar.

btw, has a new fuel filter also.

I have about 3-4 dataloggs from various customers cars that are experience the same situation. The hesitation is in the same place 600mb, and does the same thing (i.e goes really lean). I have toyed with the throttle tip in settings to make it richer, but it doesnt make much of a difference. Some cars experience the problem, others dont. I still havent quite figured out what is going on yet, other than the blip of a lean condition for a fraction of a second. The lambda trace does not pick up the lean condition, but the lambda display at the top toolbar shows 17~18:1 for a split second.

turbo_civic_si wrote:setup:

rc 550cc injectors
resistor box
stock fuel rail
walbro 255hp pump
fpr set to 50psi @ 1 bar
purge valve disconnected
aem wbo2 w/methods mod



problem:

i've been tuning my car and for some reason everything above 600mb is lean and have to add quite of bit just to get it on the rich side. romeditor is showing me at almost 54% dc and i'm not in vtec. my multiplier is set to .436. everything below 600mb is rather rich and can come down some. which i have. but for some reason and only when i cross 600mb the car drops lean, even if i do it slow and keep it around 600mb it will drop lean and then come back up?

any suggestions?

what ECU are you using?

if you're running a p72 it could also be a problem.

I didn't have any hesistation issues with my p28, until I got my car tuned again, and the chip was burned as a p72 in a p28 box. Hesitation at 10 inch grams of vacuum (or about 600 mb).

Its very interesting.

I haven't reburned my ecu yet to p28 mode cause I have been very lazy.

I'm having the same problem and I'm using a p75 (ls) ECU. I have been part-throttle and full-throttle tuned so the maps are good. Let us know of any developments. I'll be checking this post regularly for updates.

read this link

http://hondata.com/bb/viewtopic.php?t=745

same idea/problem. i have advanced the timing in colum 6 to about 40*. i still have some hesitation at 3k and i don't have a romulator to do on-the-fly tuning, so when ever i get around to advancing the timing, i'll do it.