Idle Adjust procedures on KA24DE 240sx with pictures. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

zerodameaon · 07-09-2011, 07:01 PM

So I am going to toss some info up here because i had a hard time finding photos in Search. This is how to adjust your idle with pics

1: Drive your car around the block a few times to get it up to temp.

2: unplug the TPS.

Step 3: Find the adjustment screw. Its on the intake side of the motor by the fire wall. Here is a picture.

Turn the screw clockwise to lower idle. counter clockwise to raise idle. Set your idle to 700rpm.

This is also a great time to do your ignition timing, it should be set at 20*.

Hope this helps someone.

KA24DE IACV New. http://www.frsport.com/Nissan-OEM-24...V_p_12512.html

Vacuum line diagrams

LOADING... · 07-13-2011, 06:12 AM

Gonna Do mine tomorrow, thanks for the pics bro!!

zerodameaon · 07-14-2011, 09:22 AM

No problem hope it helps.

Edwin562 · 07-14-2011, 09:32 AM

nice lil write up

07sitos13 · 06-25-2012, 11:18 PM

yep. found this helpful. the screw is on your iacv if that helps you find it better.

dkim1985 · 08-29-2012, 05:08 PM

Great write up!

So what does it mean when you unplug the TPS anddd your idle adjust screw is turned all the way clockwise and you're still idling at 1200rpm? =\

project-c2 · 08-29-2012, 09:34 PM

Quote:

Originally Posted by dkim1985

Great write up!

So what does it mean when you unplug the TPS anddd your idle adjust screw is turned all the way clockwise and you're still idling at 1200rpm? =\

IACV is stuck, throttle plate adjusted wrong, throttle cable adjusted wrong, throttle plate bent. IDK if I missed anything. Could be anything of the nature.

zerodameaon · 08-30-2012, 03:22 AM

Check your throttle body. The shaft for my throttle body was bent somehow not letting it open past 50% but not quite close all the way. After that search around on the forum here, there is a thread about cleaning your IACV with it still on the car, and check for vacuum leaks.

psychos13 · 08-30-2012, 03:50 AM

Nice write up gonna adjust mine tomorrow

dkim1985 · 08-30-2012, 09:37 AM

Quote:

Originally Posted by project-c2

IACV is stuck, throttle plate adjusted wrong, throttle cable adjusted wrong, throttle plate bent. IDK if I missed anything. Could be anything of the nature.

Quote:

Originally Posted by zerodameaon

Check your throttle body. The shaft for my throttle body was bent somehow not letting it open past 50% but not quite close all the way. After that search around on the forum here, there is a thread about cleaning your IACV with it still on the car, and check for vacuum leaks.

Thanks guys.
What I've done so far is adjusted the throttle plate, throttle cable, set TPS, no leaks. I'll try cleaning IACV, just bought a can of Throttle and Intake cleaner.

zerodameaon · 08-30-2012, 12:45 PM

Adjust that idle screw back and forth well cleaning. There is probably a chunk of something stuck in there.

dkim1985 · 08-30-2012, 03:54 PM

Quote:

Originally Posted by zerodameaon

Adjust that idle screw back and forth well cleaning. There is probably a chunk of something stuck in there.

How about I unplug the TPS, unscrew the idle screw to open it up a bit and then use the intake cleaner to the IACV while keeping it revv'd up. Should be good like that, right?

zerodameaon · 09-12-2012, 03:13 AM

Yeah that is easiest if you have a second person to help out, then you don't have to worry about not having a third arm.

dkim1985 · 09-12-2012, 11:30 AM

Quote:

Originally Posted by zerodameaon

Yeah that is easiest if you have a second person to help out, then you don't have to worry about not having a third arm.

so i did all that anddd...didn't change a thing. im sure it cleaned the inside a bit but.. i still have a high idle. i think theres a leak somewhere so mine might be a different issue. thanks though!

tapdeznutz · 09-13-2012, 11:11 PM

there is also a little screw with a lock nut that adjusts the opening of the throttle plate. check that too. might be adjusted way too much.

dkim1985 · 09-13-2012, 11:32 PM

Quote:

Originally Posted by tapdeznutz

there is also a little screw with a lock nut that adjusts the opening of the throttle plate. check that too. might be adjusted way too much.

already checked that.
I've set it at the idle when the car is rolling. when it comes to a standstill, then the idle will go up.

tapdeznutz · 09-14-2012, 10:05 AM

Quote:

Originally Posted by dkim1985

already checked that.
I've set it at the idle when the car is rolling. when it comes to a standstill, then the idle will go up.

ok back track a bit, what about resetting the TPS?

dkim1985 · 09-14-2012, 02:23 PM

Quote:

Originally Posted by tapdeznutz

ok back track a bit, what about resetting the TPS?

I adjusted the throttle position bolt, adjusted TPS, idle screw is turned all the way right, sprayed intake/throttle cleaner to clean IACV..
and I'm still idling at about 1200 at standstill.

I believe there is a leak from the 'exhaust header to egr pipe'..because that corner of the engine gets hot after driving for awhile. but don't know if that'll really affect the idle at standstill because isn't the egr supposed to be closed at standstill?

tapdeznutz · 09-14-2012, 02:37 PM

check vaccum lines. i know if i unplug certain vac lines that idle would jump.

dkim1985 · 09-14-2012, 04:05 PM

Quote:

Originally Posted by tapdeznutz

check vaccum lines. i know if i unplug certain vac lines that idle would jump.

Any suggestions on which and what order to start unplugging and etc?

tapdeznutz · 09-14-2012, 04:11 PM

Quote:

Originally Posted by dkim1985

Any suggestions on which and what order to start unplugging and etc?

for obvious ones, i use throttle body cleaner and spray them on the vaccum likes, if change in engine speed=for sure vac leak. or just start replacing the easiest ones. vac lines are so cheap and they are fairly easy to replace u know.

dkim1985 · 09-21-2012, 01:06 PM

so i took my car into a shop just to see if those pros can figure out whats going on. they had it for 3 hours and couldn't figure it out. the guy i talked to said it's most likely the IACV going out.

so with that said, im going to change mine out with a new one but...mine currently looks like this..

same connectors...how do i unplug those connectors?? lol
and i've noticed other IACV's have different plugs, are there any differences? is it possible to just get a harness adapter or something?

tapdeznutz · 09-21-2012, 01:30 PM

slide the locking clip back and then pull connector off, i am assuming you are meaning different between sohc and dohc motors.

dkim1985 · 09-21-2012, 01:35 PM

Quote:

Originally Posted by tapdeznutz

slide the locking clip back and then pull connector off, i am assuming you are meaning different between sohc and dohc motors.

well...i have a dohc..but this is exactly how my IACV looks. most of the new new IACV's have the other connectors..

dkim1985 · 10-18-2012, 04:51 PM

Quote:

Originally Posted by tapdeznutz

slide the locking clip back and then pull connector off, i am assuming you are meaning different between sohc and dohc motors.

wheres this 'locking clip'?
do you know if theres a way to change the connector type so I can put a new IACV instead of my current older type?

If I can find a used one i'll probably do this over the weekend..gives me something to do..lol

zerodameaon · 10-20-2012, 03:22 AM

The locking clip is just a U shaped piece of metal keeping the connector from sliding off. Look very closely at the picture above with the IACV-FICD, you will see the small piece of metal, if you stick a flat head under it and pull up it will come off, just don't loose it as it tends to take flight.

Also new IACV? If its a IACV that is identical(same part number) off a newer car you can just splice in the connector if its diffrent. If its something completely different you cannot retrofit it.

dkim1985 · 10-22-2012, 10:02 AM

Quote:

Originally Posted by zerodameaon

The locking clip is just a U shaped piece of metal keeping the connector from sliding off. Look very closely at the picture above with the IACV-FICD, you will see the small piece of metal, if you stick a flat head under it and pull up it will come off, just don't loose it as it tends to take flight.

Also new IACV? If its a IACV that is identical(same part number) off a newer car you can just splice in the connector if its diffrent. If its something completely different you cannot retrofit it.

idk if i can see the locking clip on mine..maybe its facing inward..
also..apparently these older connectors are for SOHC?? but mines a DOHC??
wth nissan!? anyways will an IACV for the SOHC work on the DOHC?

zerodameaon · 10-24-2012, 02:04 AM

It might be on the bottom or something. Should look like the piece of metal in this picture and on the bottom side you cant see it almost closes the loop but there is a gap in there to allow it to be removed.

As far as SOHC and DOHC, if you can find the one for the dual cam and remove the doubts, they are probably the same inside but the sensors may be different.

dkim1985 · 10-24-2012, 12:14 PM

Quote:

Originally Posted by zerodameaon

It might be on the bottom or something. Should look like the piece of metal in this picture and on the bottom side you cant see it almost closes the loop but there is a gap in there to allow it to be removed.

As far as SOHC and DOHC, if you can find the one for the dual cam and remove the doubts, they are probably the same inside but the sensors may be different.

Thanks for the picture! helps a lot!
I had someone contact Nissan about the IACV connectors and these old connectors were pretty much decommissioned (big surprise...) and they said you can just hardwire the new connectors to the harness and use the newer replacements.
I think I will be doing this later on..

For now, seems as though my situation has changed.
I dont think my IACV is the problem..there seems to be an air leak somewhere back there.
I can hear a hissing sound and the idle flucuation/high idle has gotten a lot worse and will die when city driving.
At this moment, my mechanic has it and is going to do an evap/smoke test.
We'll see whats going on. Will update later.

sx261 · 10-25-2012, 09:25 AM

so I've been having this issue...
when coming to a standstill.. for example like at a stoplight... i sometimes experience a fluctuation idle.
Any ideas to as what this could be?

08-29-2012, 05:08 PM	#6
dkim1985 Zilvia Addict Join Date: Apr 2011 Location: Gardena, CA Posts: 771 Trader Rating: (28) Feedback Score: 28 reviews	Great write up! So what does it mean when you unplug the TPS anddd your idle adjust screw is turned all the way clockwise and you're still idling at 1200rpm? =\ __________________ FS: Nismo R-Tune Camshafts for VQ35DE.

08-30-2012, 03:50 AM	#9
psychos13 Zilvia FREAK! Join Date: Dec 2010 Location: Long Beach, Ca Age: 29 Posts: 1,184 Trader Rating: (13) Feedback Score: 13 reviews	Nice write up gonna adjust mine tomorrow __________________ UNDER DESTRUCTION!: 91 s13 Top Secret Build

09-13-2012, 11:11 PM	#15
tapdeznutz Nissanaholic! Join Date: May 2011 Location: Long Beach Age: 41 Posts: 1,801 Trader Rating: (50) Feedback Score: 50 reviews	there is also a little screw with a lock nut that adjusts the opening of the throttle plate. check that too. might be adjusted way too much. __________________ FS: DSS 1pc Steel Non ABS, 6bolt axles WTB: Boost Gauge, Hatch Roof Wing

09-14-2012, 02:37 PM	#19
tapdeznutz Nissanaholic! Join Date: May 2011 Location: Long Beach Age: 41 Posts: 1,801 Trader Rating: (50) Feedback Score: 50 reviews	check vaccum lines. i know if i unplug certain vac lines that idle would jump. __________________ FS: DSS 1pc Steel Non ABS, 6bolt axles WTB: Boost Gauge, Hatch Roof Wing

09-21-2012, 01:06 PM	#22
dkim1985 Zilvia Addict Join Date: Apr 2011 Location: Gardena, CA Posts: 771 Trader Rating: (28) Feedback Score: 28 reviews	so i took my car into a shop just to see if those pros can figure out whats going on. they had it for 3 hours and couldn't figure it out. the guy i talked to said it's most likely the IACV going out. so with that said, im going to change mine out with a new one but...mine currently looks like this.. same connectors...how do i unplug those connectors?? lol and i've noticed other IACV's have different plugs, are there any differences? is it possible to just get a harness adapter or something? __________________ FS: Nismo R-Tune Camshafts for VQ35DE.

07-13-2011, 06:12 AM	#2
LOADING... Join Date: Dec 2010 Location: Honolulu,HI Posts: 33 Trader Rating: (0) Feedback Score: 0 reviews	Gonna Do mine tomorrow, thanks for the pics bro!!

07-14-2011, 09:32 AM	#4
Edwin562 Post Whore! Join Date: Nov 2009 Location: Whittier (562) Age: 31 Posts: 4,721 Trader Rating: (35) Feedback Score: 35 reviews	nice lil write up

06-25-2012, 11:18 PM	#5
07sitos13 Join Date: Jun 2012 Location: sumter sc Age: 34 Posts: 17 Trader Rating: (0) Feedback Score: 0 reviews	yep. found this helpful. the screw is on your iacv if that helps you find it better.

09-21-2012, 01:30 PM	#23
tapdeznutz Nissanaholic! Join Date: May 2011 Location: Long Beach Age: 41 Posts: 1,801 Trader Rating: (50) Feedback Score: 50 reviews	slide the locking clip back and then pull connector off, i am assuming you are meaning different between sohc and dohc motors. __________________ FS: DSS 1pc Steel Non ABS, 6bolt axles WTB: Boost Gauge, Hatch Roof Wing

10-25-2012, 09:25 AM	#30
sx261 Join Date: Jul 2012 Location: Merced Age: 27 Posts: 17 Trader Rating: (0) Feedback Score: 0 reviews	so I've been having this issue... when coming to a standstill.. for example like at a stoplight... i sometimes experience a fluctuation idle. Any ideas to as what this could be?

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