Surging idle problem - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

ThunderbaySr20 · 12-27-2008, 03:34 PM

hey zilvia...

I posted this on nico the other day, and now im posting here cuz i havent got a response... LOVE IT

hey all, i just replaced my IACV with a brand new one...now i have a surging idle problem, it hovers around 2000 rpm... thats with the mafs unplugged...with it plugged in it goes up to 2500...

just curious if i should re-remove my intake and change my IACV again... and i went over all my wiring and the mafs wiring checks out.

anyone got any other suggestions?

thanks

S13 redtop
BCC 264
SAFC
KA MAFS
GT2865RS

cotbu · 12-27-2008, 05:51 PM

Why are you unplugging the mafs? At operating temp, unplug the tps, adjust idle, then turn off car, plug tps back in. start car. Take note of current idle...If you mean with the mafs plugged it it will only rev to 2500rpm, then...that's a different problem not discussed here in this post! You do mean you have a ka24e mafs, right?

ThunderbaySr20 · 12-27-2008, 06:07 PM

yea, its the ka24E maf. thing is, when i do unplug the tPS, i cant adjust the idle, it only idles higher with the IACV screw.... im gunna start over and pull the intake again...

cotbu · 12-28-2008, 05:00 AM

Well if you haven't pulled the intake yet? Put the ecu in timing mode, then adjust the idle. you may have a leak somewhere....? Did you check things like, throttle plate and cable? Was the IACV plugged in.

What I would do, is put the car in timing mode, and check the timing. If you can't get the car in timing mode, the ecu is still in control, and you change anything.

The other thing you can try, which is also possible, but not too probable is let the ecu learn the new iacv on it's own.

There are steps and procedures for putting the ecu in timing mode.

ThunderbaySr20 · 12-28-2008, 11:31 AM

i know how to put the ecu in timing mode...

warm it up, disconnect tps, etc...

i checked the new iacv for leaks and it still revs high, im wondering tho, whenever i use pliers and clamp the IACV rubber hose closed it idles down no problem...

ThunderbaySr20 · 12-28-2008, 11:32 AM

also ive leak tested the whole setup a bunch of times, i got none...

cotbu · 12-28-2008, 02:08 PM

when you clamp the hose, your doing what the iacv is supposed to do.
Is the screw, screwed all the way in?
I think you may have to drive the car a little and see if the ecu learns the IACV, Just keep an eye on rpm when coming off throttle. If you have a consult cable and program you could see how much the IACV opens and closes as the ecu learns.

12-27-2008, 03:34 PM	#1
ThunderbaySr20 Join Date: Nov 2008 Location: Ontario Age: 39 Posts: 30 Trader Rating: (0) Feedback Score: 0 reviews	Surging idle problem hey zilvia... I posted this on nico the other day, and now im posting here cuz i havent got a response... LOVE IT hey all, i just replaced my IACV with a brand new one...now i have a surging idle problem, it hovers around 2000 rpm... thats with the mafs unplugged...with it plugged in it goes up to 2500... just curious if i should re-remove my intake and change my IACV again... and i went over all my wiring and the mafs wiring checks out. anyone got any other suggestions? thanks S13 redtop BCC 264 SAFC KA MAFS GT2865RS

12-27-2008, 05:51 PM	#2
cotbu Post Whore! Join Date: Sep 2005 Location: SWFL Age: 50 Posts: 3,318 Trader Rating: (3) Feedback Score: 3 reviews	Why are you unplugging the mafs? At operating temp, unplug the tps, adjust idle, then turn off car, plug tps back in. start car. Take note of current idle...If you mean with the mafs plugged it it will only rev to 2500rpm, then...that's a different problem not discussed here in this post! You do mean you have a ka24e mafs, right? __________________ LoverTechnologies "Half Broken Things!"

12-28-2008, 05:00 AM	#4
cotbu Post Whore! Join Date: Sep 2005 Location: SWFL Age: 50 Posts: 3,318 Trader Rating: (3) Feedback Score: 3 reviews	Well if you haven't pulled the intake yet? Put the ecu in timing mode, then adjust the idle. you may have a leak somewhere....? Did you check things like, throttle plate and cable? Was the IACV plugged in. What I would do, is put the car in timing mode, and check the timing. If you can't get the car in timing mode, the ecu is still in control, and you change anything. The other thing you can try, which is also possible, but not too probable is let the ecu learn the new iacv on it's own. There are steps and procedures for putting the ecu in timing mode. __________________ LoverTechnologies "Half Broken Things!"

12-28-2008, 02:08 PM	#7
cotbu Post Whore! Join Date: Sep 2005 Location: SWFL Age: 50 Posts: 3,318 Trader Rating: (3) Feedback Score: 3 reviews	when you clamp the hose, your doing what the iacv is supposed to do. Is the screw, screwed all the way in? I think you may have to drive the car a little and see if the ecu learns the IACV, Just keep an eye on rpm when coming off throttle. If you have a consult cable and program you could see how much the IACV opens and closes as the ecu learns. __________________ LoverTechnologies "Half Broken Things!"

12-27-2008, 06:07 PM	#3
ThunderbaySr20 Join Date: Nov 2008 Location: Ontario Age: 39 Posts: 30 Trader Rating: (0) Feedback Score: 0 reviews	yea, its the ka24E maf. thing is, when i do unplug the tPS, i cant adjust the idle, it only idles higher with the IACV screw.... im gunna start over and pull the intake again...

12-28-2008, 11:31 AM	#5
ThunderbaySr20 Join Date: Nov 2008 Location: Ontario Age: 39 Posts: 30 Trader Rating: (0) Feedback Score: 0 reviews	i know how to put the ecu in timing mode... warm it up, disconnect tps, etc... i checked the new iacv for leaks and it still revs high, im wondering tho, whenever i use pliers and clamp the IACV rubber hose closed it idles down no problem...

12-28-2008, 11:32 AM	#6
ThunderbaySr20 Join Date: Nov 2008 Location: Ontario Age: 39 Posts: 30 Trader Rating: (0) Feedback Score: 0 reviews	also ive leak tested the whole setup a bunch of times, i got none...