need idle help

paintballer317 · 10-23-2009, 03:38 AM

ok, so i recently did a timing belt and water pump change and changed all vacuume lines and powder coated the intake manifold. when i got it running again, the idle is kinda screwy. the car runs AWESOME but when i start it cold, it revvs by itself up and down over and over and over till it warms up. and the idle is slightly high. i tightened up the throttle cable a little bit so there was no slack, could this have made the idle problem happen? but other than that, the car runs amazing

Mrmerlin · 10-23-2009, 04:08 AM

loosen the cable a turn or two see if it makes any changes,, see if you have a throttle position sensor if so it should click when the throttle is just opened or closed just before the stop

paintballer317 · 10-23-2009, 05:11 AM

ok, i loosened the cable to where it has a visable amount of slack, same thing. it revvs by itself and the low point of the revv is still high. it does have the throttle position sensor, there are 2 switches, it clicks when you move the throttle from idle and theres one at the other end of the throttles motion. so one on each side.

paintballer317 · 10-23-2009, 05:27 AM

could it maybe have to do with vaccume lines?

paintballer317 · 10-23-2009, 06:32 AM

i figured it out, it was the big throttle adjustment screw in the front of the throttle body right behind the oil fill container. i started the car so it was revving up and down by itself and slowly screwd in the big screw in front till it stopped revving. then after a few seconds the idle dropped down to where its supposed to be at the deep rumbling idle... i love that sound

BIMMERMIKE · 10-23-2009, 06:58 AM

My idle screw is turned in all the way and still have high idle.
I did a intake refresh with good vacuum(18") tried pressurising the system with no apparent leaks.
Where do I go from here?
One sympton: it idles at 750 when cold and gradually raisesd to 900. I used a idle gun to determine idle speed, another observation idle is never steady , bounces around eg. 750, 825, back to 750.

Thanks

paintballer317 · 10-23-2009, 07:50 AM

try checking your throttle cable, im sure youve done this already, check and make sure the sensor switches are working correctly and so that it clicks when you barely move the throttle. try pulling the screw out, maybe its in too far. im defenitly not an expert by any means but thats what i would try

JhwShark · JhwShark's Garage

Quote:

Originally Posted by paintballer317

try pulling the screw out, maybe its in too far. im definitely not an expert by any means but thats what i would try

Another possibility is that the screw may have been tightened to much. I know from helping on idle issues in the past, that when I pulled the screw out, the needle like point had been flattened slightly from the over tightening. I replaced the screw and spring; all fixed! Not sure if this could happen on a Shark, I've never needed to pull my screw out. But I do remember someone saying years ago...never over tighten an idle needle screw; the needle needs to stay as a needle.

Trying to help!
Jon

MPDano · MPDano's Garage

Another thing is that A/C Idle Valve hanging on the crossbar will raise your idle. Maybe it's stuck open? I believe if you disconnect the wires, this should close the valve. Or if the valve is bad, you could pinch the hose and see if this changes the idle.

Danglerb · 10-23-2009, 10:56 PM

With an 86 is likely the Idle Stabilizer Valve.