Preventing stall with PowerFC?

[sqd]

So I have this little annoying problem - when driving and suddenly put the clutch pedal down, the revs will drop down low enough to make the car stall.

Lowering the speed with a gear engaged, then clutching out when the revs are near idle, it won't stall.

And, yes, I'm running an atmospheric BOV, the SSQV, and im aware that this can happen. But i think i've read somewhere that you can prevent this somehow with the PowerFC? I've searched and googled and didn't really find anything.

I'll recirculate the BOV sooner or later, but I wanted to know if theres something that'll temporarily fix it.

[sidewaysil80]

i had the same thing happen to me when i switched from map sensor back over to mafs. funny thing was i was atmospheric LONG before i had the map sensor...i never figured it out. but it bothered the shit out of me. oh and on the afc neo the setting your looking for is decel air function. so i'm pretty sure its the same on the power fc. hope that kinda helps...

[fliprayzin240sx]

i had the same thing happen to me when i switched from map sensor back over to mafs. funny thing was i was atmospheric LONG before i had the map sensor...i never figured it out. but it bothered the shit out of me. oh and on the afc neo the setting your looking for is decel air function. so i'm pretty sure its the same on the power fc. hope that kinda helps...

That doesnt make sense, if you have a PFC D-jetro using a MAP sensor, you shouldnt have any stalling issue related to running an open BOV. If you know the difference between the way a MAP and MAF works, you'd know why. The MAF setup's problem why it stalls out is due to the engine loosing metered air out of the BOV, that the ECU sent a specific amount of fuel for. The car is stalling due to that extra fuel...

MAP sensor doesnt care about metered air, runs off pressure that it senses in the intake manifold. The downside of a MAP setup is, it is sensitive to temperature changes. Remember, colder air is denser vs warm air. Your tune may work better on cooler air or not, all depends on when it was tuned.

[sidewaysil80]

i had the same thing happen to me when i switched from map sensor back over to mafs. funny thing was i was atmospheric LONG before i had the map sensor...

That doesnt make sense, if you have a PFC D-jetro using a MAP sensor, you shouldnt have any stalling issue related to running an open BOV. If you know the difference between the way a MAP and MAF works, you'd know why.

yes clearly i understand the diff between map/maf or else i wouldnt have spent 1000+ on a djetro version. re read what i wrote. i had no issues with atmospheric before i went with power fc djetro nor during. it wasnt until after i downgraded to afc neo/z32 mafs that i ran into problems.

[sqd]

i had the same thing happen to me when i switched from map sensor back over to mafs. funny thing was i was atmospheric LONG before i had the map sensor...i never figured it out. but it bothered the shit out of me. oh and on the afc neo the setting your looking for is decel air function. so i'm pretty sure its the same on the power fc. hope that kinda helps...

Hm, I googled for that function, and from what i can gather, the power fc doesn't have it? Or is it just called something else?

I'm at work, so i can't check my PFC either.

[sidewaysil80]

Hm, I googled for that function, and from what i can gather, the power fc doesn't have it? Or is it just called something else?

I'm at work, so i can't check my PFC either.

search for anything with decelration air maybe...

[sqd]

I did, googled for all sorts of things, didn't find anything :/ All results are about the S-AFC..

[landins13]

its all in the tune, my car did the same thing, but once i got the tune rite at idle my car catches itself everytime now, from time to time the idle is a little lower then id like it to be, but im on nistune and i was able to tune the car for idle, usually the problem is once youve swapped maf's or to a map or vice versa the car isnt tuned to idle with that particular map/maf.

if youve got you k constant dead on at idle then the car will catch, richening it up at idle will help a little too, im not talking stupid rich but instead of idleing at 14.7 dead on idle around 14.2. and you should be money.

i know exactly what youre talking about though if you come to a stop sign and shift from 3rd to nuetral the rpm drops and the car stalls unless you catch the throttle, or you have to down shift every single gear until when you go into nuetral you are at 800 rpm. its a pain in the ass

[MudRacer]

I had the same problem for a while, Adding the VSS helped. When the engine sees the speed is slowing down it adjusts the idle and it doesnt stall as much as it used to. But the Idle is still way below what I would like it to be.

From what I've read. Using an AFC should fix this problem.

[rican_nick]

I battled this for a while to. As stated above its just in the tune. When I had my power FC self tune it would Idle low and cut off almost 100% of the time on de accell. From helping a friend tune a SAFC I remembered the DeAccell settings on the SAFC however... there was no equivalent that I could find in the PFC. Steve Shadows sent me a base tune and 90% of the time I dont have any problems with deaccell now. With my AC on (it bumps idle up) I dont have any issues at all. I need to get the car fine tuned to get it all 100%.

[Sil-Eighty SE-K]

^what changes did he make in the tune.... i have this same issue in my r32 built rb26 single turbo

it stalls all the damn time unless i rev down to what it idles at..... if im doing parking manuvers it will stall over and over... i dont even have to be coming off high revs.... i notice its very rich when this occurs.... i tried turning up the TB stop and cranking the idle rpm in the pfc... no help.

im thinking of pulling fuel in those cells i get near at idle and coming off revs....

[bradg1313]

I had the same problem, everyone was telling me to go blow thru (put the MAF on the cold side) I finally did and it fixed my problem, hope this helps

[jspaeth]

That doesnt make sense, if you have a PFC D-jetro using a MAP sensor, you shouldnt have any stalling issue related to running an open BOV. If you know the difference between the way a MAP and MAF works, you'd know why. The MAF setup's problem why it stalls out is due to the engine loosing metered air out of the BOV, that the ECU sent a specific amount of fuel for. The car is stalling due to that extra fuel...

MAP sensor doesnt care about metered air, runs off pressure that it senses in the intake manifold. The downside of a MAP setup is, it is sensitive to temperature changes. Remember, colder air is denser vs warm air. Your tune may work better on cooler air or not, all depends on when it was tuned.


I have a lightweight flywheel, D-jetro PFC, and decent cams, and my car idles okay, but still "dips" down to maybe 500 RPM on a hard decel, then catches itself.


2 things

1) The tune makes a differences

2) The condition of the IACV makes a HUGE difference.

3) Cams make a HUGE difference......ever since switching over from stock to bigger cams (264 12 mm lift), even when trying to RE-learn idle using the PFC, the car's idle is a bit twitchy....


I think that is one of the bigger downfalls of the PFC (even though I really like it personally).....you cannot control any of the parameters that control the IACV and it's feedback.