idlig problem. idle is at 3000k

[spider_slayer]

lately my idle has bn a litle messed up. it will sparadically jump up to about 2000. at first i thought it was a vac leak, but since it doesn't happen steadly and sometimes wil idle fine it really can't be.

then today while driving home from school i was coming to a stop light, disengauged the clutch and the rpms shot up to 3k and held there till i launched. its only happened a couple times but that scares me. i can't blow this engine too.

i work today, but tommorow i'll pull codes from the ecu, unplug the tps, and try the mafs.

any have any suggestions where to start?

chezdik - djpants, help me out guys!

[S13FASTBACKSR]

it sounds like it could possibly be your tps going bad ..sometimes it is putting out the correct voltage at idle and other times it is putting out too high of voltage at idle causing your engine to idle as high as 3000 rpms

[ronald240]

does your car idel regularly then when your cars is up to temp. does it jump up and down ex. 1000rpms to 2000rpms then back down...if so i think its your "IDEL AIR CONTROL VALVE"...it happend to my homies 240...

[spider_slayer]

update*** went out and started the car cold. steady idle at 2000. unpluged the mafs and the idle began to violentely jump form 1500 to 2000. killed the car and plugged it back in.

waited about 20 min and did some other stuff like clean the underbody and look for leaks.

from cold start again started the car and it had a steady idle at around 1500. unplugged the tps and the idle began to creap up to about 2500 and held. so i think the tps may jsut not be aligned correctly.

will check codes later and keep you updated.

[Jiggyfry]

Had this problem a while back, went away. Yesterday im in traffic and the idle starts goin nuts. It would jump up to 1700 then fall down to 400rpms. Sometimes itll stall out too. Ive already cleaned out my Iacv and it was perfect. Im gonna check my tps tomorrow (again, 3rd time) to be sure and see what i get.

Seems like this is a common problem that never gets a definite answer.

[S13FASTBACKSR]

when your engine is warm and running you need to check your tps voltage..should be .45volts to .55volts at idle and at w.o.t. your voltage should be 4.5...... if its off then just adjust the tps with the 2 screws

[spider_slayer]

thats what i'm gonna do when i get a volt meter.

anyone want to suggest a volt meter? i'll probally jsut get a basic craftsman one cause i usally don't mess with electrical stuff.

[DjPantsSpecR]

i bought the 10 dollar craftsman one, its pretty good.

alright, one time i had a ridiculous idle problem, and the car was idling at around 2k. i had the tiniest little piece of carbon built up on the throttle plate. so i would take off all the intake stuff and clean that.

i never cleaned my IACV, i plugged it instead. put a spark plug in the rubber hose connecting to the intake, and plug the intake hole accordingly. then take note of the idle, if its still ridiculously high, you know air is being leaked in somewhere between your MAF and the throttle body.

the tiniest leak before the throttle body can easily cause a huge idle jump.

so i would get a foot and a half length of hose that fits well in your ear. you can listen for vac leaks everywhere.

i would check:junction between maf and filter, hose and resonator, all lines running into the intake, and running out (check the tee'd one) between rubber boot and intake, and rubber boot and tb.

then if thats not it, you can look around the huge orings where the injectors nestle into, where the manifolds meet, and at the head.

however, i shoudl say if there was a vac leak, you'd be able to hear it at idle as a high pitched noise.

[92'240sx]

ok heres a problem ive been having as well... when my 240 idles it idles at 1000k. its perfectly fine until i get up to speed and i come up on a stop. as soon as i apply the clutch to take it out of gear the rpm go way too low and sometimes kills the motor and i have to restart. when it doesnt kill the motor the rpms go back to 1000k. so the problem is keeping the rpms steadily at 1000. any ideas? this is driving me crazy!!!

[DjPantsSpecR]

that sounds like a vac line going to the EGR has fractured. its most likely the biggest one going from the bottom of the bpt valve.

so welcome to NICO sir, and find that vac leak. jsut like i said before, larger vac leaks sound liek a high pitched noise, while smaller ones may not sound at all.

[92'240sx]

I checked over the vac lines and you were right. the smallest vac line connected to the intake was actually pinched off. thanks alot!!! i owe you one big time!!! - Gabe

[DjPantsSpecR]

happy to save people money.