Ok, I have tried to source a solution for this in the past. At lower rpms, generally, but not limited to less than 3000, at roughly 20-30 percent throttle, around 90-120 load my wideband drops off the chart. Everytime, in a decreasing fashion. There is sometimes a random negative timing number shown in a log. Ive been searching for accellerator enrichments and all sort of other types of issues. Has anyone ever seen these symtoms?

 

Try.....

ECU Periphery0 (FAA) - bit. 10 - "weird unknown" timing pull at light accel. less then 3000rpm

0=Disable

 

Done, didnt work, this happens at 4000+ too but is really prevalent at lower rpms

 

the brick wall is probably the fuel cut which is showing on your wideband.

 

What injectors are you running? Who dialed them in?

 

Its def not a fuel cut. This happened on a stock rom with stock injectors, and it happens on a v7 with pte 1000cc injectors that I used figures from the supermerge injector thread that are pretty accurate. Happens if I force open loop and tune all the cells aswell.

 

I have this exact same problem and it is definitely not a fuel cut. I logged it last night and there is no difference in injector pulse width.

-Acree

 

does yours happen around 20+% throttle? Is it mivec? I thought it was the transiition from open loop to closed loop causing a problem, so I forced open loop, started tuning that way and its no wheer in the mapping.

 

20 to 40% throttle. I'm pretty sure it has nothing to do with mivec.

-Acree

 

still sounds like a fuel cut. on v7 check your fuel cut multiplier and fuel cut load x1 and x2.

 

what makes you think its a fuel cut? theres no part throttle fuel cut settings afaik, and im making around 14.5psia so I am so far from the fuel cut its not funny. I would also expect to see a mroe lean condition at a fuel cut not a overly rich type like I am seeing.

 

I'll say it again...

I'm currently working on it right now. Taking advice from KevinD at Evo Dynamics, I richened the cells between 2500-3500 and 100-140 load by 0.5 points. It seemed to lessen the harshness of the hesitation.

I believe the problem occurs when the car is coming out of closed loop. I'm going to fiddle with it some more tonight and see if I can't iron the problem out.

-Acree

 

keep me posted. Im sittin in my car wtih my laptop now, but its goiing to die soon, so no tuning for me for a few hours.

FWIW a stock 100% bpv, did make the problem less nticable by some degree, because it is easily confused with as the surging feeling caused by a bpv that is overly crushed,backwards etc. I thought it was the bpv not opening at first mine was crushed so far, something the previous owner did. but i put a stock evo x one on and the problem was still there. i definatley concur with the problem being one as coming out of closed loop. thats the only thing I can think of.

 

I richened everything in that range up by 0.9 points and everything surrounding it by 0.4. It my 10 minutes of driving (trying to recreate the problem) I was unable to recreate the hesitation. This may be a fix for the issue. I'll have to drive it around for a few more days to make sure.

-Acree

 

i don't know if this is similar to the same problem that i have every once in awhile, but mine is at a much lower rpm. I will say that switching to the big synapse bov helped my hesitation problems tremendously.