Idles Drops When Rev!

[gL3nJaMiN88]

the last few months i've had nothing but problems with my R33 . Right now i've got this stupid idle issue when the car is hot, not when its cold. What the car does is it starts fine and revs and a nice steady rate, but as soon as you blip the throttle anywhere past 3000rpm the revs go under 500 to around 0 then bounce up to 500 then back to 0 sounding like a rotory and pissing black smoke trying to save stalling then it goes back to normal. Ive cleaned my AAC Valve 2 times with good carby cleaner , new gasket for the AAC valve , New Plenum gasket , Ive cleaned the throttle body and i've positioned the TPS to what is says in Nissan RB25 workshop manual which is 0.40v. I've got a brand new Bosch 02 genuine and just bout done everything . I've searched every forum and NOBODY is having the same issues! .. I've adjusted idle with the gay TPS unplugged like it says in idle and im running PowerFC so i cant adjust it on the ECU .

NOW the only way to stop the rev hunting issue when i rev the car is to adjust that scew thingo that pushed the Butterfly open or closed on the throttle body , so my car revs at 1500RPM and eveything is fine! it revs nice and comes straight back and sits on the rev and doesnt drop! . The car even feels better to drive as it doesnt stall when i boost 1st gear and then back to neutral ..

But the only issue i dont want my freakin car to idle at 1500!!! i want it to idle at 750RPM at the most..

Not one mechanical workshop knows what im talking about and probably half you guys wont but there must be a solution before i run this car off the cliff and sell the scrap

[blind_elk]

DO NOT ADJUST THE THROTTLE STOP SCREW (the "screw thingo").

You are running a PFC - the problem will be in the tune of the PFC, possibly in the throttle over-run settings.

[gL3nJaMiN88]

I already moved that thing!! where should it be? it doesnt state it in the manual??? and i already said i cleaned the AAC Valve 2 times? and i mean really cleaned it with freakin cotton wool buds and carby clean+ compressed air! .. what else can contribute?

[gL3nJaMiN88]

Also! on your powerFC's? whoever has them in ur REV/IDLE setting on Power FC what is ur Fuel Cut under Closed Throttle set at? should be 3RD RPM setting from the bottom up?

[lachlanw]

its your blow off valve and its called pcf disease . do a search

Edited December 8, 2009 by lachlanw

[gL3nJaMiN88]

its your blow off valve and its called pcf disease . do a search

how about you do a search under the description i have wrote? you wont find shit! i just want my freakin car to work and my blow off valve was blocked off in the test and did the same thing , i just tried my stock one and it is the same so its not that

[Penfold]

My car did a similar thing with warm starts with the PowerFC where it would hunt. I ended up using datalogit to try to relearn the start up procedure but it got worse. Took it to the tuner and they said it was leaning out which was causing the problem. They fixed it up and ever since its been fine.

Edited December 8, 2009 by Penfold

[boostn0199]

its either your bov or if you have bloked off your bov and the recirc pipe is bloked off aswel it will do this just set ur idle to like 800 from the powerfc settings not the way you did and it will be alright

[Bunta]

I have had a similar problem on 2 occasions

1) it was an air leak, check all your piping

2) dead airflow meter and busted wiring to the AFM

Cant promise your case is the same but it would be worth checking out

[YaskY]

i done my head in over the same thing for a couple weeks,

mine ended up being air/vacumn leak via my catch can being plumbed up wrong to my pcv,

[rasonline]

I had that issue with BOV vent to atmosphere. went back to recirc BOV's

[lachlanw]

there is a new thread every week along these lines . its either an air leak ( block the afm and pump up the whole system with air compressor ) or its power fc disease . it it to do with air reversion back out the air flow meter . when you rev it up engine sucks in air when you let off the air has to go somehwere some goes out the blow off valve or in your case it all goes backwards out the air flow meter and as the air flow meter and ecu dont know the difference between air flowing in and air flowing out it sees air going in and puts lots of fuel in .