no matter what i do with this datalogit, i cannot get the car to stop surging when i come back on the throttle after decel (decel fuel cut activated)

in haltech there is a setting called "fuel cut restore" that shoots an amount of fuel in to "catch up" after decel fuel cut. does this exist in powerFC?

surely people havent been using this ECU for the last 20 years without this feature.

 

Raise the fuel cut RPM settings.

 

so, "no" ?

effectively disabling the fuel cut is not a fix.

 

That is not disabling anything unless you raise the fuel cuts to 8000rpm.

The FC (fuel cut) settings are the points where the system starts injecting fuel again. Which is exactly what you are asking for. If you have it set at 1200rpm it starts injecting fuel once it reaches 1200 on decel.

Page 33 http://www.banzai-racing.com/store_i...werFC_FD3S.pdf

 

thanks chris. i'm familiar with the RPM floor settings you're referring to. that's not what i'm asking for. maybe my post wasn't quite clear.


i'm talking about the RPM not falling all the way to that floor, but driving in gear, decelerating, and pressing the accelerator again while still in gear.
ex: you're at 3000rpm in 5th gear on the interstate, you let off the throttle to decelerate (activating the decel F/C, full lean) then you press the accelerator again at about the same RPM. there is a lean spike every time, and there's no "fuel cut restore" setting to give the injection a "boost" to catch up (not to catch it from stalling on "free fall" full decel like you're talking about).

the only setting I can find that even gets close to helping this post-F/C lean spike is the accelerator pumps, which weren't made to fix this. I can increase the light throttle accel pumps and it helps slightly, but it negatively affects the light throttle touches everywhere else.

 

It was not clear.

Now that I know what the problem actually is. It sounds like you need to add some fuel into the deep vacuum cells of the map at the RPM range that you are having the issue.

Having the car on a dyno makes identifying the exact cells very easy.

 

i did that. it didn't fully fix it.


so, "no" ?

 

Your car has a problem that is not PFC related or it needs to be properly tuned. Since you did not list any of your mods, there is no telling what the real issue is. Could be a slow reacting or faulty fuel pump resistor, faulty fuel pressure solenoid, etc.

Every PFC car is not driving around stumbling when coming out of decel.

 

Post your map, a log of the problem occurring, and list of mods. Then we can have something granite to analyze.

 

With 850 primaries, my car is smooth as can be under the conditions you describe. I couldn't get it to buck or stumble even if I tried. There definitely may be something extra going on with you car

 

OK thanks for the responses guys.

my datalogit is no longer working on my cheap laptop for some reason. i'll tinker with this Wednesday and see if I can fix it, and use a different laptop to log.

 

Any update on this? This is an interesting topic

 

I don’t know if he ever fixed this but I have the same issue and have been in a few other Pfc cars and felt the same thing. It’s as though you get a hesitation when starting to lean back into the throttle. I’m not complaining or in a position to test things to fix it at this time as the car is down for body work, but I wanted to note I have had the same problem in a few different cars with the Pfc.

 

For anyone interested I have solved this programming issue in powerfc.
If anyone is still interested I can explain it

 

Nothing a couple of shots of ouzo couldn't fix!