Tannhauser Posted May 20, 2009 Share Posted May 20, 2009 Curses, I've mistyped the thread title! Recently, the car has been revving at around 2000 rpm on idle. As far as I recall, this was an intermittent problem, but when I took the car out today, it was persistent. Every time I dip the clutch, up come the revs. The car seems to be running fine apart from that. I know that a possible cause is a sticking idle control valve.I spent about an hour trying to get the damn thing off with no success ( I have knackered the screw in the process, too). I also cleaned the throttle cam thingy. I started it up and sprayed WD40 into the inlet and was wonderfully pleased that it was idling at around 1000rpm. However, after packing up, I noticed that I had unplugged the valve when the engine was running. I haven't restarted it and tried again with it plugged in - I have to really watch the noise with the neighbours as it's a bit like the space shuttle. I will get someone competent to look at it, but in the meantime, two questions: 1) Is it feasible that unplugging it might stop the high idling and 2) Can I take the car anywhere with the unit unplugged, just until I get it looked at? Or is this going to damage something? (sorry that's a third question) I've got an AEM ECU if that's relevant. Quote Link to comment Share on other sites More sharing options...
bignum Posted May 20, 2009 Share Posted May 20, 2009 I don`t think it will run at all with the idle valve unpluged, sounds like the valve needs cleaning, or have you had the battery off recently, i need to adjust the idle vs target table on mine after ive had the battery off. Quote Link to comment Share on other sites More sharing options...
Tannhauser Posted May 20, 2009 Author Share Posted May 20, 2009 I don`t think it will run at all with the idle valve unpluged, sounds like the valve needs cleaning, or have you had the battery off recently, i need to adjust the idle vs target table on mine after ive had the battery off. Thanks for the reply. Yep, battery has been off. It's been off before and not caused a problem. I really hope it's not an adjustment on the map - everything about that is a major pain in the arse. If it's the valve, I hope spraying some WD40 in the inlet might have done something. Quote Link to comment Share on other sites More sharing options...
madmarf Posted May 20, 2009 Share Posted May 20, 2009 it will run with it off, what will happen is the revs will go up then down then up then down quite quickly. Quote Link to comment Share on other sites More sharing options...
JamieP Posted May 20, 2009 Share Posted May 20, 2009 I thought the ICV only worked for cold starts? so would not be doing anything when the car is up to temp? On my old red supra i had no idle control valve, worked perfectly as its mapped to run without one. Quote Link to comment Share on other sites More sharing options...
Tannhauser Posted May 20, 2009 Author Share Posted May 20, 2009 OK, that sounds promising. If it's responsible, I can unplug it until I can get it to someone with a brain that can fix it. Ta. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted May 20, 2009 Share Posted May 20, 2009 A sudden idle problem will usually be down to the throttle pot out of adjustment, and yes you can setup the throttle so as it will run fine without the ICV, however it is controlled all the time by the ECU, as its actually a stepper motor. Quote Link to comment Share on other sites More sharing options...
bignum Posted May 20, 2009 Share Posted May 20, 2009 I thought the ICV only worked for cold starts? so would not be doing anything when the car is up to temp? On my old red supra i had no idle control valve, worked perfectly as its mapped to run without one. If t/f did it then would defo be blanked off probably with their trademark walking stick end:rolleyes: I think it would need to be setup to run without it, mine cirtainly uses it all the time. Quote Link to comment Share on other sites More sharing options...
Terminator Posted May 20, 2009 Share Posted May 20, 2009 The IAC will park where ever it is when switched off. If left disconnected I am pretty sure it will hold that position until it receives a signal to alter its position. Quote Link to comment Share on other sites More sharing options...
Tannhauser Posted May 21, 2009 Author Share Posted May 21, 2009 Thanks for the replies. I drove the car to work this morning and it was revving like a b*stard. Drove it back again and it was fine. The fact that it's intermittent makes me think that it's an occasionally sticking valve, rather than an adjustment needed on the map - which I presume would give me a more consistent problem.. Quote Link to comment Share on other sites More sharing options...
Ryan.G Posted May 21, 2009 Share Posted May 21, 2009 It will be the valve sticking Cliff.... Best thing to do for the time being until you can take it off and clean. When it is idling fine at say 1000rpm, unplug the connector and the stepper motor will then stay still. When cold though it will idle lower around 700rpm i guess until warm. The closed loop control set on your map will try and compensate to bring the idle up with the ignition timing so it might be alright but i think when its cold is might idle abit to low. Ryan Quote Link to comment Share on other sites More sharing options...
Tannhauser Posted May 21, 2009 Author Share Posted May 21, 2009 Great! Thanks, Ryan, I will try that. Quote Link to comment Share on other sites More sharing options...
Homer Posted May 21, 2009 Share Posted May 21, 2009 Just to back up what has been said before, I had exactly the same symptoms on mine, it was just a sticky idle control valve. Cleaned it out and all was fine (it was absolutely caked in gunk!) Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 22, 2009 Share Posted May 22, 2009 Wash it out with brake cleaner when you remove it, that usually works. You can change a thread's title if you go to the "Advanced" edit options. Quote Link to comment Share on other sites More sharing options...
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