Trizimo

Hello,
I’m new to this forum. I apologize if I’m breaking any rules. Anyways, I own a 1998 Nissan 240sx with a Sr20det Blacktop swap. I’ve been having some issues with it recently and can’t seem to figure it out. Maybe someone out there can help me.

The car has an occasional miss and has issues idling. I’ve checked and replaces the sparkplugs, coilpacks, cleaned the maf, cleaned the throttle body, replaced the tps, replaced the fuel filter and I’m still having some issues. I got rid of the occasional miss, but I’m still having an issue with idling.
My boost gauge reads -17 when idling (I believe that’s vacuum. I just got the car and I’m new to all of this. Please bear with me) and I was told it’s supposed to be around -21.


THE PROBLEM that I continue to have is (1), it will occasional fail to idle properly and will sound like a muscle car. In other words, its idle will fluctuate from 700-1100. (2) When making sudden stops (or when pushing the clutch in while in mid rpms) the car will not idle down properly, it will go down to about 500 rpms where then it gasp for life.

MY QUESTION then is what should I check next? I was thinking vacuum lines first and possible the iacv. Does this problem sound familiar or am I overlooking anything? If neither of those things work, my next option was to set it on fire.

Thanks!

Trizimo

I've also adjusted the iacv and the crank position sensor. It did not help that much.

Any help would be GREATLY appreciated!

ultimateirving

Sounds like iacv no doubt. You can take it off and clean it properly and readjust the idle. There is a method to adjusting idle on the sr20, so if youre new take your time and research

__________________
Z32 with lq4 swap
Desert Street Scene || Dssevents.com

Trizimo

Crap, sorry I keep thinking of things. The car is not throwing any codes either. This whole thing is weird because sometimes it'll idle fine and then other times its just awful.

To save me from adding another post (lol), Ultimateirving, thank you! This is problem a lame question but does the iacv also control the idle when braking (or with the clutch pushed in)?

Kingtal0n

the bypass valve is leaking

those are symptoms of metered air leaking from the system

__________________
5.3/4l80e/turbo 240sx playthrough:
https://tinyurl.com/turbo240

Trizimo

What should it be at? Again, sorry, this is all new to me

ultimateirving

Do you have an atmospheric blow off valve? if so then stumbling on pedal lift when the rpms drop off can be common. Also the iacv is in control of opening when the rpms get low to keep it from stalling; so if its sticky or non-op then it can cause it to stall or really stumble erradically

__________________
Z32 with lq4 swap
Desert Street Scene || Dssevents.com

Trizimo

Thank you so much! I appreciate the explanation too. I'm ordering the part tomorrow. Hopefully everything will go well otherwise I'll be back haha.

Thanks again