asupracar Posted December 9, 2004 Share Posted December 9, 2004 Hi guys another problem has occurred Stuck in traffic 1hr car starts acting really weird. 1st engine stalled on acceleration I then restart the car The rev rise quite high (rev 4) then it goes back down It can’t settle on an idle. it just travels from 1.5revs to 4rev- up and down continuously. Some times it settles (seconds or so) then all happens again. Red triangle came on once but has been off ever since. AA had to tow me home, as it was un-driveable AA recon it’s a throttle sensor ANY IDEAS WOULD BE APPRECIATED P.S I’ve reset the ECU no luck. NOW CARS COOLED DOWN-IT DEVELOPED A NEW SYPTOM. When I start the car the revs rise to 3 000-4000 rpm then as the revs begin to fall the rev counter goes nuts up and down up and down then a flick of the engine managment light- then back to normal idle. WEAIRD!!! Link to comment Share on other sites More sharing options...
Ian C Posted December 9, 2004 Share Posted December 9, 2004 TPS sensor - if the ECU can't see it's signal (i.e. it's unplugged, failed, wire broken, bad contact) then it defaults to a 100% open state. Idle speed control valve stuck open/connection lost. The revs increase as they aren't being controlled and the engine management uses, I'm not sure what, probably ignition timing or injector cut, to control the engine speed and avoid an overrev situation. Sounds like it's a multimeter-at-the-ECU situation to me -Ian Link to comment Share on other sites More sharing options...
asupracar Posted December 10, 2004 Author Share Posted December 10, 2004 Hi- ill check the TPS- another thing that happened this morning was when I started it the car idled OK- however the rev counter (not the engine speed) when crazy up and down up and down anyore ideas appriciated. Iam not very good at testing sensors so any detail help would be great!! Anyone got a TPS kicking about that I could have for a small few Link to comment Share on other sites More sharing options...
asupracar Posted December 10, 2004 Author Share Posted December 10, 2004 can someone point out the TPS please Thanks Link to comment Share on other sites More sharing options...
Ian C Posted December 10, 2004 Share Posted December 10, 2004 Oooh - rev counter. That sounds like a bad connection as well, from your Vehicle Speed Sensor. Have you got a speed delimiter fitted? Much work done around the ECU with things like boost controllers and piggyback ECUs and stuff? The TPS on that picture is not the one circled but it looks like that - see attached pic. http://www.ian.chisholm.clara.net/mkiv/enginepics/eng_side_intake_front.jpg -Ian PS free sneak preview of some of the tech section images coming your way with the forum upgrade Link to comment Share on other sites More sharing options...
tDR Posted December 10, 2004 Share Posted December 10, 2004 I've had similar problems as a result of a speedo / odo / delimit conversion chip acting up... Cheers, Brian. Link to comment Share on other sites More sharing options...
ardasaliah Posted December 10, 2004 Share Posted December 10, 2004 Its a Uk so no delimiter or speedo conversion Link to comment Share on other sites More sharing options...
asupracar Posted December 10, 2004 Author Share Posted December 10, 2004 Yep is a UK no delimiter or any conversions. ECU not been touched. So am I right in thinking that the 1st thing I should do is replace the TPS ( £117 from toyota) Is there anyway to check if its def the TPS without buying a new one. Skint - christmas here etc. It would really help if the location of the sensors to check are pointed out as I have no clue about the electrical side of things. 2nd thing to check is speed sensor? not sure where that is? thanks guys Link to comment Share on other sites More sharing options...
bedlam Posted December 10, 2004 Share Posted December 10, 2004 Had the exact same problem and it was the ISCV,which dont mean that it's your problem, but see if you can get someone to let you try theres out on your car. They where nearly 300 quid to buy. Andy Link to comment Share on other sites More sharing options...
asupracar Posted December 10, 2004 Author Share Posted December 10, 2004 Sorry mate not sure what the ISCV is? + where Cheers Link to comment Share on other sites More sharing options...
Ian C Posted December 10, 2004 Share Posted December 10, 2004 The throttle position sensor is labelled at the top of that piccy I attached. The ISCV is the Idle Speed Control Valve, named "Idle Control valve" on this pic: http://www.ian.chisholm.clara.net/mkiv/enginepics/eng_top_intake.jpg Now, you can check if sensors are working properly, but you need a multimeter, access to the ECU and it's wiring loom (Passenger footwell), an ECU pinout diagram (see attached zip file, US spec = UK spec), and an idea of what the throttle position sensor should give, voltage wise, in various states of open-and-shutness. That I can dig out for you if you are willing to take up the job of checking these things out for yourself There are known cases of the idle control valve sticking open/shut/somewhere in the middle and people have had success in cleaning them out with a solvent like brake cleaner. It involves some disassembly and a couple of coolant pipes have to come off if you are up for that too. -Ianecu pinouts us spec.zip Link to comment Share on other sites More sharing options...
asupracar Posted December 10, 2004 Author Share Posted December 10, 2004 I think this is the point where it becomes a little to technical. OOnOOOOO! I can hear toyota calling me. I bet its something really easy to fix and toyota charge me a bomb for doing it. ill give the volt metre a go I think. I 've got the volt readings on a supra disk- thanks for offering to dig them out! Of course any other advise still would be great! Link to comment Share on other sites More sharing options...
asupracar Posted December 10, 2004 Author Share Posted December 10, 2004 UPDATE! Start car with TPS installed- Car goes mad. (Revs ups Revs down) While it’s going mad if I disconnect the sensor- the car literally calms down. At this point the car feel ok. It has a slightly higher idle though. It has stalled a few times while I 've revved it. However the car is behaving its self while disconnected from the TPS. So would this be the most likely cause of my problems p.s sorry about all the demand for advise but iam sure you folks understand the frustration when cars go wrong. ANYONE GOT A TPS ??? Link to comment Share on other sites More sharing options...
carl0s Posted December 11, 2004 Share Posted December 11, 2004 what is the TPS? Surely it's just a potentiometer? P.S Ian, those pics are fantastic, they should be up in the tech faq, oh and if any mods are listening I'd like to suggest that the tech faq is renamed from "please help me with ...." to "Technical FAQ, Details, Pictures and Explanations of common problems" or something, and put a bit more in-yer-face so nobody misses it, and has all the nonrelavent posts removed. sorry, hijack over back to bed now! Link to comment Share on other sites More sharing options...
tDR Posted December 11, 2004 Share Posted December 11, 2004 Originally posted by carl0s oh and if any mods are listening I'd like to suggest that the tech faq is renamed from "please help me with ...." to "Technical FAQ, Details, Pictures and Explanations of common problems" or something, and put a bit more in-yer-face so nobody misses it, and has all the nonrelavent posts removed. sorry, hijack over back to bed now! All in hand carl0s... coming soon to a mkivsupra.net forum near you Cheers, Brian. Link to comment Share on other sites More sharing options...
carl0s Posted December 11, 2004 Share Posted December 11, 2004 Originally posted by tDR All in hand carl0s... coming soon to a mkivsupra.net forum near you Cheers, Brian. cool! I like all the development that's been going on here since we got lots of mods Link to comment Share on other sites More sharing options...
Ian C Posted December 11, 2004 Share Posted December 11, 2004 Carlos - that's why I put "PS free sneak preview of some of the tech section images coming your way with the forum upgrade" at the bottom of the first piccy But it could well have been somewhat obscured by the huge piccy I put up lol -Ian Link to comment Share on other sites More sharing options...
Ian C Posted December 11, 2004 Share Posted December 11, 2004 Originally posted by carl0s what is the TPS? Surely it's just a potentiometer? The TPS is a potentiometer, but it also has a switch circuit inside as well - this is the IDL circuit and tells the ECU when the throttle has opened enough to come off the idle map. -Ian Link to comment Share on other sites More sharing options...
carl0s Posted December 11, 2004 Share Posted December 11, 2004 Originally posted by Ian C Carlos - that's why I put "PS free sneak preview of some of the tech section images coming your way with the forum upgrade" at the bottom of the first piccy But it could well have been somewhat obscured by the huge piccy I put up lol -Ian Link to comment Share on other sites More sharing options...
tepster Posted December 12, 2004 Share Posted December 12, 2004 Them technical pix are superb, makes u wanna get involved in the working of ya car even when u know nowt! Now waiting for the new section to open !!! Pass me an oily rag................. Link to comment Share on other sites More sharing options...
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