Rob Posted April 2, 2007 Share Posted April 2, 2007 FUrther to my previous posts, over the weekend I cleaned out the throttle body, and cleaned out the ICV, and reassembled with a new gasket. Re-set the ECU by pulling the fuses. Now once the car is warmed up it idles around 1800-2000rpm when hot. However turn off the engine and start up again, and it idles at 700rpm. What could be wrong? There are no fault codes showing at all. Edited to say, when starting on my drive from cold, and letting it warm up, it idles as normal. THe high idling occurs only after being driven. Quote Link to comment Share on other sites More sharing options...
wez_p Posted April 2, 2007 Share Posted April 2, 2007 stretched throttle cable or it's getting stuck sometimes? Quote Link to comment Share on other sites More sharing options...
supra666 Posted April 2, 2007 Share Posted April 2, 2007 FUrther to my previous posts, over the weekend I cleaned out the throttle body, and cleaned out the ICV, and reassembled with a new gasket. Re-set the ECU by pulling the fuses. Now once the car is warmed up it idles around 1800-2000rpm when hot. However turn off the engine and start up again, and it idles at 700rpm. What could be wrong? There are no fault codes showing at all. Edited to say, when starting on my drive from cold, and letting it warm up, it idles as normal. THe high idling occurs only after being driven. This is happening to my car aswell and I don't know how to rectify it, let me know how it goes as this problem is driving me insane!!! Quote Link to comment Share on other sites More sharing options...
Rob Posted April 2, 2007 Author Share Posted April 2, 2007 I'm pretty sure it's not anything mechanically sticking, as pressing the throttle when stationary would un-stick whatever it was. Also tonight, stopped at in-laws on the way home idling at 1800, switch off, and back on idling at 700. Idle stayed low while trundling around village, but building up a little speed on the road out caused it to idle at 1400 when stationary. What does the little sensor right in the front of the air intake do? Could this be anything to do air rushing in? It doesn't high idle if left to warm up, it's only after actual movement of the vehicle. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted April 2, 2007 Share Posted April 2, 2007 I had a lot of trouble with similar idle problems, i went through the adjustment procedure in the manual, and it helped, but i did have the problems come back, i think primarily its down to the throttle position sensor, although i set this so i got the specified resistance, i ended up backing it off a little in order to get the idle to settle down, also check the throttle damper setting. Quote Link to comment Share on other sites More sharing options...
Scooter Posted April 2, 2007 Share Posted April 2, 2007 list of high engine idle causes per manual 1) Switch condition signal circuit 2) ISC valve circuit 3) A/C signal circuit (compressor circuit) 4) ECU power source circuit 5) Backup power source circuit there's pages of stuff............. 1) has a possible faulty throttle position sensor at fault 2) a ISC valve Rob i have these on an engine in the garage if you want to try them i could remove them and pop them in the post......... Quote Link to comment Share on other sites More sharing options...
Rob Posted April 3, 2007 Author Share Posted April 3, 2007 Hang on, I'll try the throttle re-set malarky first. Which manual are we talking about here, not the standard car one? Quote Link to comment Share on other sites More sharing options...
Scooter Posted April 3, 2007 Share Posted April 3, 2007 Which manual are we talking about here, not the standard car one? nah one of CJ's workshop ones........... Quote Link to comment Share on other sites More sharing options...
Ian C Posted April 6, 2007 Share Posted April 6, 2007 If you sit idling at 700rpm, then lift the revs to 2500 on the throttle and hold them for say 10 seconds and let it drop, what's the result? -Ian Quote Link to comment Share on other sites More sharing options...
Rob Posted April 6, 2007 Author Share Posted April 6, 2007 Just did that, from slightly cold, and also hot. Revs fell back to around 1000 each time, although immediately after driving at 50-60mph, the revs were at 1800 when idling an also after raising to 2500 for 10 secs. I'm pretty sure it's the vacuum valve thing at the back of the throttle body, with the throttle arms all at "zero" I can reach in and press the little metal lever with my finger and the revs instantly fall to 800. Perhaps the little rubber piston thing is sticking a bit. Quote Link to comment Share on other sites More sharing options...
Rob Posted April 6, 2007 Author Share Posted April 6, 2007 I'm pretty sure it's not anything mechanically sticking, Or maybe not, the little black thing I though was part of the vac system seems to be just a damper for the throttle shut-off. I removed and cleaned it, stretched the internal spring a bit. Refitting gave no result though, idle still varies between 1200 to 1800 rpm and if I reach to the back of the TB and press the circled lever idle drops to 800. It seems as if the butterfly isn't fully closing, but whilst fiddling with it disassembled I couldn't discern any movement from "shut under return spring pressure" to "pressed shut by hand" Quote Link to comment Share on other sites More sharing options...
Rob Posted April 8, 2007 Author Share Posted April 8, 2007 Burmp Quote Link to comment Share on other sites More sharing options...
TLicense Posted April 8, 2007 Share Posted April 8, 2007 Give the connector for the throttle position sensor a good waggle. I'm willing to bet it's a loose connection in there. Well that's what was wrong with mine. Quote Link to comment Share on other sites More sharing options...
Rob Posted April 8, 2007 Author Share Posted April 8, 2007 Ok, I've also bought a multimeter, so I'll be checking the readings across the IAC valve. ...and trying Scooters spares, nice chap that he is. Quote Link to comment Share on other sites More sharing options...
TLicense Posted April 8, 2007 Share Posted April 8, 2007 Honestly Rob, check the TPS connector. I had exactly the same symptoms and that's what it turned out to be. With the engine running and the revs high, remove the plug. I imagine it will make no difference. If the revs rise a little then it's not this, but my betting it is. Quote Link to comment Share on other sites More sharing options...
Rob Posted April 8, 2007 Author Share Posted April 8, 2007 I'll try tomorrow, but this afternoon I checked the resistence across the IAC and all was within the required 10-30 Ohm range, but I removed the IAC valve and hooked it up to the battery in sequence. I could feel the stepper motor jump but it wouldn't wind in or out. I refitted with the valve halfway extended, and from cold, idle was about 900, lower than previously. However it was quite warm in the air tonight, but the lower cold idle was consistant with the valve not working in it's new position. Prior to doing this, the cold idle has self adjusted as normal, I presume it is the IAC which controls this and no other factor? Went for a quick drive and after it still idled at 1800, pressing the butterfly lever dropped it back to 800. I'll remove the IAC again tomorrow to see if it's position has changed from how I left it, which should confirm whether it works or not. Again, the throttle butterfly seems to close against the damper, but I can see no play in it that would correspond with me being able to reduce revs by pressing on it by hand. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted April 9, 2007 Share Posted April 9, 2007 Check the ecu temp sender (not the temp gauge sender) resistance, hot and cold. Quote Link to comment Share on other sites More sharing options...
CANDYMAN666 Posted April 9, 2007 Share Posted April 9, 2007 Hi I've got the same problem too.......only also get alternate flashing OD off and Traction control light off once its had a Good bit o Booooooooooooooosstt. Does anyone think these are related.....or have anything to do with the mph conversion chip ????? Quote Link to comment Share on other sites More sharing options...
Rob Posted April 9, 2007 Author Share Posted April 9, 2007 Check the ecu temp sender (not the temp gauge sender) resistance, hot and cold. OK where be that? What should the readings be? Also update, IAC is fine, it had repostioned itself after running in the car, and was adjusting idle from cold. No effect from jiggling the TPS connector either. The problem definitely only occurs after actual driving of the car, and there is clearly about 2-3mm of travel left in the throttle lever to close the throttle down. This is not caused by the little damper. I sprayed all the linkages with lube, penetrant but to no effect. Quote Link to comment Share on other sites More sharing options...
TLicense Posted April 9, 2007 Share Posted April 9, 2007 Did you try unplugging the TPS connector completely? It should cause the IAC to back all the way out making it idle high. If it's a dodgy connection somewhere the IAC will already be backed out. If the revs suddenly rise then the ECU does have control over the IAC (so the TPS signal is good) it's just telling it to go to the wrong place for some reason. (Probably a sensor) I don't think the IAT sensor would have that much of an effect, but check that. It's on the inlet plenum. The other sensor to check is the coolant sensor which is on the water elbow, which is the bit of metal on the other end of the top radiator hose to the radiator. Quote Link to comment Share on other sites More sharing options...
Rob Posted April 10, 2007 Author Share Posted April 10, 2007 Further thoughts, the throttle doesn't fully shut after a moderate speed run, but when I switch the engine off, it shuts fully. What's holding it open? What is the little pipe that connects to the top of the TB? It has no suction in it, or air blowing out, and it joins to the a pipe heading down the back of the block. Quote Link to comment Share on other sites More sharing options...
Scooter Posted April 10, 2007 Share Posted April 10, 2007 Rob are you refering to the pipe in the diagrams attached? if so these attachments may be some help........ By the way i've just seen this again and am thinking that maybe a whole throttle body may be a better way of sorting this............you could always compare the two to find out what part is faulty on yours.....(tbh i'd rather send you the whole thing than swear and curse at removing the sensors!) Sorry i've been a bit slack, I'll fish the whole thing out tomorrow. Quote Link to comment Share on other sites More sharing options...
Rob Posted April 10, 2007 Author Share Posted April 10, 2007 That's the pipe, the one on the right, I don't have the LH one at all, or the device it's plugged into. Seems a bit harsh where the manual blithly says "replace the TB" Quote Link to comment Share on other sites More sharing options...
Rob Posted April 11, 2007 Author Share Posted April 11, 2007 Did you try unplugging the TPS connector completely? It should cause the IAC to back all the way out making it idle high. If it's a dodgy connection somewhere the IAC will already be backed out. If the revs suddenly rise then the ECU does have control over the IAC (so the TPS signal is good) it's just telling it to go to the wrong place for some reason. (Probably a sensor) I don't think the IAT sensor would have that much of an effect, but check that. It's on the inlet plenum. The other sensor to check is the coolant sensor which is on the water elbow, which is the bit of metal on the other end of the top radiator hose to the radiator. Ok, did that, no effect while it was running hot and high revs, but when i switched off and immediately re-started, it idled at normal 700 and dis-connecting the TPS caused the revs to rise. Any diagrams to show the two sensors you mean, and the same for what CW said? Another note, while it was idling high after driving, I watched the throttle lever (the one I can push shut to return revs to normal) and whilst watching, pulled the connector on the Dizzy cap to kill the engine. I could see the throttle lever move slightly to close as the engine died. I'm convinced something is holding the butterfly open but I don't understand how if it's purely a mechanical device connected to a cable. Quote Link to comment Share on other sites More sharing options...
Ian C Posted April 11, 2007 Share Posted April 11, 2007 It's probably engine vacuum going through that hose in the pictures attached above that is nerfing the throttle open a bit for some reason (NA's are not my forte). Try removing the hose and temporarily blocking the feed barb on the throttle, and see if it still drops the throttle shut when you kill the engine. -Ian Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.