Ka24 won't idle - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Dirtydave · 04-29-2009, 06:09 PM

Car cranks then will stumble and die out, unless I rev it and after 3000 rpm or so it smoothes out. If I disconnect the maf it idles fine. I have replaced the maf, and that it not the problem unless I have two bad mafs. I tried the ever elusive search button and have found a few threads pertaining to the IACV. I believe my next step is to verify the timing and clean the IACV, possibly run some Seafoam. Other than that I am out of ideas. Anyone have other suggestions?

rob_g · 04-29-2009, 06:14 PM

I recommend checking for trouble codes first and working from there based on the results.

Dirtydave · 04-29-2009, 06:15 PM

Forgot to mention this is a sohc to dohc swap, so no consult port.

d0pe240 · 04-29-2009, 07:47 PM

check timing and maybe ecu?

Dirtydave · 04-29-2009, 08:06 PM

Replaced ecu, can try another though.

Dirtydave · 04-30-2009, 04:25 PM

Today I replaced ECU, Removed and cleaned IACV, seafoamed the engine from the brake booster vacuum. Nothing has changed, engine still stumbles, shakes and will barely run, runs good above 3500 rpm though.
I checked for vacuum leaks with carb cleaner and believe I have found something. When I spray the cleaner on the injectors/O-rings, I get a drop in idle. I am guessing the o-rings are bad, or not properly seated. What is a good method to reinstall the injectors and ensure they are seated and not leaking vacuum?

MARKO76 · 05-17-2009, 08:26 PM

I'm sorry I may sound stupid for asking this, but... What exactly is the IACV, and where is it? Also how do you clean it?

Dirtydave · 05-18-2009, 06:38 AM

Quote:

Originally Posted by MARKO76

I'm sorry I may sound stupid for asking this, but... What exactly is the IACV, and where is it? Also how do you clean it?

It is the Idle Air Control Valve. Its it located on the passenger side, on the backside of the engine. Your brake booster vacuum hose should be plugged into it. To clean it you can either remove it and dissemble and clean it. Or you can spray manifold cleaner into where the vacuum hose connects. It is a little tricky to keep the car running, have to do it quickly, and has to manifold cleaner. I have heard other cleaners such as carb cleaner and brake cleaner could damage it.

Dirtydave · 05-18-2009, 06:40 AM

Problem now solved, had injector o-ring leak, and bad maf. Pleae close thread.

04-29-2009, 06:09 PM	#1
Dirtydave Join Date: Nov 2008 Location: Vidor, TX Age: 50 Posts: 45 Trader Rating: (1) Feedback Score: 1 reviews	Ka24de won't idle Car cranks then will stumble and die out, unless I rev it and after 3000 rpm or so it smoothes out. If I disconnect the maf it idles fine. I have replaced the maf, and that it not the problem unless I have two bad mafs. I tried the ever elusive search button and have found a few threads pertaining to the IACV. I believe my next step is to verify the timing and clean the IACV, possibly run some Seafoam. Other than that I am out of ideas. Anyone have other suggestions?

04-29-2009, 06:14 PM	#2
rob_g Join Date: Dec 2008 Location: WA Sate Age: 35 Posts: 30 Trader Rating: (0) Feedback Score: 0 reviews	I recommend checking for trouble codes first and working from there based on the results.

04-29-2009, 06:15 PM	#3
Dirtydave Join Date: Nov 2008 Location: Vidor, TX Age: 50 Posts: 45 Trader Rating: (1) Feedback Score: 1 reviews	Forgot to mention this is a sohc to dohc swap, so no consult port.

04-29-2009, 07:47 PM	#4
d0pe240 Zilvia Junkie Join Date: Jun 2007 Location: lol Posts: 459 Trader Rating: (3) Feedback Score: 3 reviews	check timing and maybe ecu?

04-29-2009, 08:06 PM	#5
Dirtydave Join Date: Nov 2008 Location: Vidor, TX Age: 50 Posts: 45 Trader Rating: (1) Feedback Score: 1 reviews	Replaced ecu, can try another though.

04-30-2009, 04:25 PM	#6
Dirtydave Join Date: Nov 2008 Location: Vidor, TX Age: 50 Posts: 45 Trader Rating: (1) Feedback Score: 1 reviews	Today I replaced ECU, Removed and cleaned IACV, seafoamed the engine from the brake booster vacuum. Nothing has changed, engine still stumbles, shakes and will barely run, runs good above 3500 rpm though. I checked for vacuum leaks with carb cleaner and believe I have found something. When I spray the cleaner on the injectors/O-rings, I get a drop in idle. I am guessing the o-rings are bad, or not properly seated. What is a good method to reinstall the injectors and ensure they are seated and not leaking vacuum?

05-17-2009, 08:26 PM	#7
MARKO76 Join Date: May 2009 Location: Ms. Posts: 12 Trader Rating: (0) Feedback Score: 0 reviews	I'm sorry I may sound stupid for asking this, but... What exactly is the IACV, and where is it? Also how do you clean it?

05-18-2009, 06:40 AM	#9
Dirtydave Join Date: Nov 2008 Location: Vidor, TX Age: 50 Posts: 45 Trader Rating: (1) Feedback Score: 1 reviews	Problem now solved, had injector o-ring leak, and bad maf. Pleae close thread.