sohc idle madness! - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

undesiredshoe · 09-11-2006, 07:46 PM

Ok, I cleaned my iacv or whatever. When i put it back on, the idle is at 1400rpm. I turn off the car and unplug the tps. I turn it back on and the idles at 800rpm. I turn the car off and plug the tps together and turn the car on. The idle goes back to 1400rpm.

With the tps unplugged, i turn the idle screw out and the idle goes up. I then turn it clockwise to when it stops turning. The idle is at 750-800. What the **** is wrong? Its pissing the **** outta me!!! Someone HELP!

SimpleSexy180 · 09-11-2006, 08:02 PM

have you checked for any vacuum leaks?

undesiredshoe · 09-11-2006, 08:17 PM

I dont think it would be a vaccum leak. Because wouldnt the idle be crappy. I mean my idles good, its just really high.

If i unplug the tps while engine is running, the idle raises then drops to 800rpms. Then when i plug it back in the idle raises again.

Also, if i turn my tps clockwise all the way, the idle drops to 750 rpms. But with the turned like that, its not reading .5v anymore so it would be off.

idlafie · 09-13-2006, 02:56 AM

Use the SEARCH feature here on Zilvia.Net to find a link for an 89-90 Factory Service Manual. Once you download the FSM, read the section on Setting Idle. If I recall correctly, you HAVE to disconnect the TPS harnes to adjust your timing & idle. It sounds like you're adjusting the idle properly, but you might also have to readjust the timing. Your motor is supposed to idle at 750 RPM with the TPS disconnected. Download the FSM & read up on the Setting Idle procedures. The FSM will clarify all your questions...
ID

95zilvia · 09-13-2006, 03:07 AM

ok, do it in this order.
adjust TPS ( please do it the correct way )
check FSM for the specs and adjust it right.
after that.
unplug ur TPS so that ur idle is at whatever 800 or 750 or whatever u can get it to
DO YOUR TIMING.
then, plug back ur TPS
tell me what happens then.

undesiredshoe · 09-13-2006, 02:00 PM

yea the only thing i havent done is timing...ill do that.

im thinking the problem is timing

09-11-2006, 07:46 PM	#1
undesiredshoe Zilvia Addict Join Date: Sep 2005 Location: Wisco Age: 35 Posts: 787 Trader Rating: (2) Feedback Score: 2 reviews	sohc idle madness! Ok, I cleaned my iacv or whatever. When i put it back on, the idle is at 1400rpm. I turn off the car and unplug the tps. I turn it back on and the idles at 800rpm. I turn the car off and plug the tps together and turn the car on. The idle goes back to 1400rpm. With the tps unplugged, i turn the idle screw out and the idle goes up. I then turn it clockwise to when it stops turning. The idle is at 750-800. What the ** is wrong? Its pissing the ** outta me!!! Someone HELP!

09-13-2006, 02:56 AM	#4
idlafie Zilvia Addict Join Date: Mar 2004 Location: ..So Cal.... Posts: 940 Trader Rating: (0) Feedback Score: 0 reviews	Use the SEARCH feature here on Zilvia.Net to find a link for an 89-90 Factory Service Manual. Once you download the FSM, read the section on Setting Idle. If I recall correctly, you HAVE to disconnect the TPS harnes to adjust your timing & idle. It sounds like you're adjusting the idle properly, but you might also have to readjust the timing. Your motor is supposed to idle at 750 RPM with the TPS disconnected. Download the FSM & read up on the Setting Idle procedures. The FSM will clarify all your questions... ID __________________ Weekend Mechanic for my Not-So-Mechanically-Inclined buddies....

09-11-2006, 08:02 PM	#2
SimpleSexy180 Post Whore! Join Date: Aug 2004 Location: Cal Posts: 4,750 Trader Rating: (8) Rides Gallery: SimpleSexy180 Feedback Score: 8 reviews	have you checked for any vacuum leaks?

09-11-2006, 08:17 PM	#3
undesiredshoe Zilvia Addict Join Date: Sep 2005 Location: Wisco Age: 35 Posts: 787 Trader Rating: (2) Feedback Score: 2 reviews	I dont think it would be a vaccum leak. Because wouldnt the idle be crappy. I mean my idles good, its just really high. If i unplug the tps while engine is running, the idle raises then drops to 800rpms. Then when i plug it back in the idle raises again. Also, if i turn my tps clockwise all the way, the idle drops to 750 rpms. But with the turned like that, its not reading .5v anymore so it would be off.

09-13-2006, 03:07 AM	#5
95zilvia Nissanaholic! Join Date: Jun 2003 Location: South San Francisco Age: 39 Posts: 1,860 Trader Rating: (0) Rides Gallery: 95zilvia Feedback Score: 0 reviews	ok, do it in this order. adjust TPS ( please do it the correct way ) check FSM for the specs and adjust it right. after that. unplug ur TPS so that ur idle is at whatever 800 or 750 or whatever u can get it to DO YOUR TIMING. then, plug back ur TPS tell me what happens then.

09-13-2006, 02:00 PM	#6
undesiredshoe Zilvia Addict Join Date: Sep 2005 Location: Wisco Age: 35 Posts: 787 Trader Rating: (2) Feedback Score: 2 reviews	yea the only thing i havent done is timing...ill do that. im thinking the problem is timing