SR20det idle after rpm issues

[MindbenderDK]

Hi all.

Im new to these forums, but have been sneaking around here earlier

My first post here is about my 1997 Silvia with SR20det blacktop.
I bought is last spring knowing it had issues but confident i could solve them on my own.

Now one year later i still havent found the source of the problem

When accelerating and de-cellerating in gear there is no problems.
If i press the clutch from above 2.000rpm and let it hit idle, it goes below idle and dies.
It's like it doesn't catch it when the rpm drops



I have checked the basics; all vacum hoses, plugs and switches that i could possibly think off and find.

The car has had following mods made:

Apexi Power FC ECU with commander (all maps and settings are SPOT ON!) It makes 325bhp at 13PSI. AFR is perfect on idle and full load.
Greddy Intake (brand new and installation re-checked)
HKS SSQV (brand new and installation re-checked)
HKS front mounted intercooler
Z32 MAF with apexi air filter (brand new and installation re-checked)
Top mount GT2860rs (redone for external WG)
Tial ex WG (brand new and installation re-checked)
Nismo 555cc injectors (brand new and installation re-checked)
.. Probably forgot something.....

Last night i checked the IACV(idle Air control Valve) / AAC valve after i read of 2 different forums that it could mess up the idle,
but unplugging it made no difference even though ppl said that a faulty IACV is worse than an unplugged.

One of my buddies told me that the top mount turbo was interfeering with the Z32, messing up it's readings when i lift of.
Air being forced back through the MAF is what he thinks is the case here.
But to test this i would have to fit a new engine management with MAP sensor, and if this doesnt solve it i have blown thousands of $$$ on nothing...


So now to the "Fingers Crossed" part and asking on this forums if ANYBODY has an idea of what could cause this?

Cheers

[zachattack_5491]

Sorry, I know nothing about power FC. Does it have a feature to correct for venting the BOV to the atmosphere? Most cars I've driven without BOV recirc. tend to have the same issue you're describing.

[MindbenderDK]

Yeah i know some have issues with BOV's.

But the following was fitted WITH the issues, and didnt change nothing:

BOV
Greddy Intake
Z32 AFM (even switched it with another)

[Hoffman5982]

I'm really not sure of your problem, but I just wanted to give my input as far as venting the BOV. Some have problems, but I never did. I'm running the stock ecu and everything, and with it vented it idled fine, but it ran a little rich. I hope you figure out your problem. I would try maybe getting it retuned

[MindbenderDK]

Apart from the stalling after rpms, the car is running great. Before BOV and after BOV fitment it's the same. So i couldnt imagine the problem lies with the BOV.

I have had my tuner plug in his PC to recheck maps, settings and all... all was great.

[the converted]

Complete shot in the dark, but what is the rolling idle set to? Bumping it up a few hundred rpm might help.

[AZ89two4Tsx]

Recirculating your blow off valve should fix your problem.

I have pretty much your exact same setup except it only does this if I really step on it and the suddenly let off the gas, brake and press in the clutch simultaneously. Basically, putting a heavy load on the engine and then suddenly taking it away can cause it to stall, like you're experiencing. I'm no mechanic, but I'm guessing it does this because the Power FC doesn't have self correcting fuel maps like oem ecu's do.

Just recirc your blow off valve and it should go away, at least definitely help a lot.

Side note, you're making 325whp with that setup? Seems a little high to me. Do you have some super secret tune? lol...