Idle suddenly going up and down. Vid included. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

fender-startocaster · 04-16-2011, 08:51 AM

On my way home last night suddenly my idle began to fluctuate. I am not sure where to start looking to solve this problem. A link to the video is located below. There you can see the idle fluctuating. Any thoughts or ideas are appreciated

Parts replaced withing the past 6k miles
fuel pump,
fuel filter,
spark plugs and wires,
almost all vacuum hoses.

YouTube - IMG 0458

Darren · 04-16-2011, 09:42 AM

really hard to tell from inside the car, you may want to get a vid from under the hood..

Normal reasons for the idle going up and down:

- vacuum / boost leak
- air pockets in the coolant
- timing

I'd start there, and pull the codes to see if maybe a random sensor took a dump.

junn · 04-16-2011, 09:56 AM

If it just happend out of the blue most likely it's a vacuum leak

statickx991 · 04-16-2011, 10:43 AM

bleed the coolent system. look for vacuum leaks and maybe try to clean the IAC

fender-startocaster · 04-16-2011, 11:02 AM

Quote:

Originally Posted by statickx991

bleed the coolent system. look for vacuum leaks and maybe try to clean the IAC

Quote:

Originally Posted by junn

If it just happend out of the blue most likely it's a vacuum leak

Quote:

Originally Posted by Darren

really hard to tell from inside the car, you may want to get a vid from under the hood..

Normal reasons for the idle going up and down:

- vacuum / boost leak
- air pockets in the coolant
- timing

I'd start there, and pull the codes to see if maybe a random sensor took a dump.

I will check all of the above and report back. The engine is a stock kae btw so that rules out boost leak. My check engine light is not on, should i still check?

mr.booie · 04-16-2011, 01:56 PM

unplug the coolant temp sensor while it is running and see if it makes any difference. if it idles better with the temp sensor out then you need a new one. do the same with the MAF. if this doesnt work then check the IAC. thats where i personally would start. good luck. text me if you need any help.

o0o · 04-16-2011, 11:42 PM

i had that shit on my rb20det atm

clean your idle valve and replace all hoses if they're hard...i removed my coldstart valve cause it was leaking like an asshole

do some pressuretests for your intercooler piping to make it 100%sure, that all helped at me alot

fender-startocaster · 04-27-2011, 07:16 AM

Just some updates.

Replaced coolant temp sensor and problem persists.

Ive always had a very slight air leak but could never find it. Replaced most hoses in attempt to find it. I got nothing.

I unplugged the maf and iddle shot up, i unplugged the aicv and it didnt do anything. I then cleaned it and still, nothing.

I am going to pick up a few aicv from the junk yard to see if that helps.

fender-startocaster · 05-04-2011, 11:18 AM

Problem fixed!! Turns out my aicv took a dump.

04-16-2011, 08:51 AM	#1
fender-startocaster Zilvia Junkie Join Date: Jul 2009 Location: palmdale Posts: 446 Trader Rating: (6) Feedback Score: 6 reviews	Idle suddenly going up and down. Vid included. On my way home last night suddenly my idle began to fluctuate. I am not sure where to start looking to solve this problem. A link to the video is located below. There you can see the idle fluctuating. Any thoughts or ideas are appreciated Parts replaced withing the past 6k miles fuel pump, fuel filter, spark plugs and wires, almost all vacuum hoses. YouTube - IMG 0458

04-16-2011, 09:56 AM	#3
junn Zilvia Addict Join Date: Apr 2008 Location: lynwood/cpt Posts: 777 Trader Rating: (7) Feedback Score: 7 reviews	If it just happend out of the blue most likely it's a vacuum leak __________________

04-16-2011, 10:43 AM	#4
statickx991 Zilvia Member Join Date: Jan 2008 Location: Pa Posts: 210 Trader Rating: (0) Feedback Score: 0 reviews	bleed the coolent system. look for vacuum leaks and maybe try to clean the IAC __________________ im a f18 bro

04-16-2011, 01:56 PM	#6
mr.booie Zilvia Addict Join Date: Apr 2008 Location: Palmdale 93551 Posts: 769 Trader Rating: (10) Feedback Score: 10 reviews	unplug the coolant temp sensor while it is running and see if it makes any difference. if it idles better with the temp sensor out then you need a new one. do the same with the MAF. if this doesnt work then check the IAC. thats where i personally would start. good luck. text me if you need any help. __________________

04-16-2011, 09:42 AM	#2
Darren Zilvia Addict Join Date: Apr 2010 Location: kelowna, bc, canada Age: 49 Posts: 680 Trader Rating: (1) Feedback Score: 1 reviews	really hard to tell from inside the car, you may want to get a vid from under the hood.. Normal reasons for the idle going up and down: - vacuum / boost leak - air pockets in the coolant - timing I'd start there, and pull the codes to see if maybe a random sensor took a dump.

04-16-2011, 11:42 PM	#7
o0o Join Date: Feb 2011 Location: Thailand Posts: 25 Trader Rating: (0) Feedback Score: 0 reviews	i had that shit on my rb20det atm clean your idle valve and replace all hoses if they're hard...i removed my coldstart valve cause it was leaking like an asshole do some pressuretests for your intercooler piping to make it 100%sure, that all helped at me alot

04-27-2011, 07:16 AM	#8
fender-startocaster Zilvia Junkie Join Date: Jul 2009 Location: palmdale Posts: 446 Trader Rating: (6) Feedback Score: 6 reviews	Just some updates. Replaced coolant temp sensor and problem persists. Ive always had a very slight air leak but could never find it. Replaced most hoses in attempt to find it. I got nothing. I unplugged the maf and iddle shot up, i unplugged the aicv and it didnt do anything. I then cleaned it and still, nothing. I am going to pick up a few aicv from the junk yard to see if that helps.

05-04-2011, 11:18 AM	#9
fender-startocaster Zilvia Junkie Join Date: Jul 2009 Location: palmdale Posts: 446 Trader Rating: (6) Feedback Score: 6 reviews	Problem fixed!! Turns out my aicv took a dump.