Ian C Posted July 27, 2010 Share Posted July 27, 2010 (edited) Which pins on the TPS are you measuring this across? Edit to say - that sounds like the IDL switch I was talking about earlier, which of course should go from 0ohm to infinite resistance at a very slight throttle opening. Are you doing this with the TPS attached to the throttle body or is it off the car? Edited July 27, 2010 by Ian C (see edit history) Quote Link to comment Share on other sites More sharing options...
FlrSupra Posted July 27, 2010 Author Share Posted July 27, 2010 (edited) Which pins on the TPS are you measuring this across? Edit to say - that sounds like the IDL switch I was talking about earlier, which of course should go from 0ohm to infinite resistance at a very slight throttle opening. Are you doing this with the TPS attached to the throttle body or is it off the car? Multimeters Red wire to IDL and black wire to E2 (colors don`t matter I know). I put 0.50mm feeler gauge between throttle plate and screw. (It`s 0.50mm on J-Spec NA) Just loosening screws slightly so I can move the sensor very gently. So TPS is on throttle body. Then moving TPS by hand and only can get 0 Ohm or infinite reading... :/ Some guides told I should get "OL" reading to multimeter. Never seen such Car is off, but I keep it ignition on. Have I understood something wrong here, Ian? Edited July 27, 2010 by FlrSupra (see edit history) Quote Link to comment Share on other sites More sharing options...
Guest 93supra Posted July 28, 2010 Share Posted July 28, 2010 been doing some research i bet your egr valve is stuck open thats the reason for the rough idle its only suppose to open as part throttle and the blue thing is the pic is original its blue on mine it is the pcv valve..... good luck bet the egr will fix your problem Quote Link to comment Share on other sites More sharing options...
FireStormNBI Posted July 29, 2010 Share Posted July 29, 2010 open ECU. check both sides for damaged electrical components.. Quote Link to comment Share on other sites More sharing options...
FlrSupra Posted July 29, 2010 Author Share Posted July 29, 2010 open ECU. check both sides for damaged electrical components.. Will do. Thanks for the tip. Quote Link to comment Share on other sites More sharing options...
FlrSupra Posted July 30, 2010 Author Share Posted July 30, 2010 Little update on this issue. I took my car to local official Toyota Service. They thought it was timing issue, but timing was correct. Then they fiddled with TPS, but could not get any change on car behavior. They asked if I had friend with similar car so I could try different electronical parts. "We can`t help any further." was the last words, no money for checking. Quote Link to comment Share on other sites More sharing options...
jevansio Posted July 30, 2010 Share Posted July 30, 2010 So what you going to do next? Quote Link to comment Share on other sites More sharing options...
FlrSupra Posted July 30, 2010 Author Share Posted July 30, 2010 So what you going to do next? Losing my nerve I guess Naah.. few good tips still to try. Next steps: - Open the ECU and check for burning marks - Loan an MAP-sensor from another Supra owner. - Maybe buy used tested working TPS-sensor. Just to make sure :/ Quote Link to comment Share on other sites More sharing options...
jevansio Posted July 30, 2010 Share Posted July 30, 2010 I think the idea of swapping parts over is best, it may not tell you what is wrong, but it sure as hell will tell you what isn't. Quote Link to comment Share on other sites More sharing options...
Shane Posted July 30, 2010 Share Posted July 30, 2010 To be honest mate (and now wait to get shot down for saying this), there is not a lot you can do yourself once you get inside the ecu. Some of the ics are toyota specific and whats more are probably blown specifically for the supra. As far as I know, no-one has a schematic of the ecu other than maybe a block diagram. I guess if you see a dry joint or a cooked voltage reg or zener then that's different but when I took mine to pieces it was mint inside. Even if you did find a cooked resistor or something the chances are it was cooked for a reason ie. something external caused it. Really think you need to have it side by side another car and swap the TPS and other suggested stuff part by part. I apreciate there is probably not too many other cars around for you to do this. Quote Link to comment Share on other sites More sharing options...
David P Posted July 30, 2010 Share Posted July 30, 2010 Unless you are 'methodical', you will never resolve this problem. Did you ever sort out error code 25? If not, you need to check water temp sensor, air temp sensor and maybe distributor sensor. However, you appear to have, maybe, found an issue with the TPS, yet have not resolved this either? Excuse me, but if you can't work out if your TPS is working or not, I would suggest that tearing the ECU apart is not the best idea! Quote Link to comment Share on other sites More sharing options...
FlrSupra Posted July 31, 2010 Author Share Posted July 31, 2010 Unless you are 'methodical', you will never resolve this problem. Did you ever sort out error code 25? If not, you need to check water temp sensor, air temp sensor and maybe distributor sensor. However, you appear to have, maybe, found an issue with the TPS, yet have not resolved this either? Excuse me, but if you can't work out if your TPS is working or not, I would suggest that tearing the ECU apart is not the best idea! Yes that Error code 25 was solved by changing Oxygen sensors. Not a single error code after changing those sensors. And yes I`m trying to be as "methodical" as I can. 100% focused on electronical parts now. I have to try another TPS sensor aswell since I cannot adjust mine correctly through the methods and prints that I`ve been reading and some friendly mate even posted jpg-picture of the manual how to adjust TPS. When measuring TPS-sensor by the pins IDL - E2 I only can get 0 ohm reading and infinite reading so I guess the sensor never "deflect" as someone told multimeter should show "OL" reading. What are your thoughts about this David? Quote Link to comment Share on other sites More sharing options...
David P Posted July 31, 2010 Share Posted July 31, 2010 (edited) I was the 'friendly mate' who photographed the TPS pages in the manual and posted the jpeg's. I was also the friendly mate who, five days ago, recommended you changed the TPS. Like I said, be methodical. We can only help you if you help yourself. Edited July 31, 2010 by David P (see edit history) Quote Link to comment Share on other sites More sharing options...
FlrSupra Posted July 31, 2010 Author Share Posted July 31, 2010 I was the 'friendly mate' who photographed the TPS pages in the manual and posted the jpeg's. I was also the friendly mate who, five days ago, recommended you changed the TPS. Like I said, be methodical. We can only help you if you help yourself. Indeed you were. Sorry for mixing up nicknames. I could swore TPS-comment was from Ian C. I`m trying my best to help myself and sure value all of your guys help on this matter. I`ve been learning lot new when trying to solve this and hope the best the problem will be solved in very.. very near future. So.. sensors are next on the list and wishing that on upcoming week one local Supra owner here has chance and intrest to swap some parts to try on my car. Quote Link to comment Share on other sites More sharing options...
Ian C Posted August 4, 2010 Share Posted August 4, 2010 You PM'd me about the TPS stuff, that's probably the confusion I agreed with David, you need to check the TPS, alas your tests were somewhat flawed in that you had unplugged the loom from the ECU to test the pins there The ECU actually feeds the sensors with power and provides an earth for them as well, so it is essential that it remains in the loop - otherwise you get what you saw, no voltage anywhere. I'm still of the opinion that your ECU isn't seeing the IDL1 switch set, so it never goes into idle mode. Fitting the TPS is a bit of a bugger, by the way, you sort of have to "wind" it on about 90 degrees against the throttle butterfly. Don't just jam it on, look how the mechanisms work and mesh together first Quote Link to comment Share on other sites More sharing options...
FlrSupra Posted August 5, 2010 Author Share Posted August 5, 2010 You PM'd me about the TPS stuff, that's probably the confusion I agreed with David, you need to check the TPS, alas your tests were somewhat flawed in that you had unplugged the loom from the ECU to test the pins there The ECU actually feeds the sensors with power and provides an earth for them as well, so it is essential that it remains in the loop - otherwise you get what you saw, no voltage anywhere. I'm still of the opinion that your ECU isn't seeing the IDL1 switch set, so it never goes into idle mode. Fitting the TPS is a bit of a bugger, by the way, you sort of have to "wind" it on about 90 degrees against the throttle butterfly. Don't just jam it on, look how the mechanisms work and mesh together first Yea those PM`s had to confuse me or some :/ That "winding tps on about 90 degrees" got me thinking and today I had to check how does the mechanism really work. Still. Measuring E2-IDL pins I only can get 0 or Infinite-reading on Ohm meter and the best position for TPS-sensor is far right (full throttle). That position makes car idle like on the video. Every other position will make idle worse. Oh.. and also when on idle and you push the throttle pedal slowly it will "pop all over" and struggle with the revs. For example if you keep the revs on 2000rpm with throttle it will make faster pops from exhaust that it makes on stationary idle. Also tried following method. I kept car running and turned the TPS-sensor slowly. Every millimeter from extreme right position to left made the idle worse. Found a new tested TPS here on Supraclub and decided to buy one since I can`t get anybody here to give it for a test :/ Quote Link to comment Share on other sites More sharing options...
jay n_a Posted August 5, 2010 Share Posted August 5, 2010 i have a 95 j-spec and i have the same problem! mine even cuts out when i come to a stop going down hill Quote Link to comment Share on other sites More sharing options...
FlrSupra Posted August 10, 2010 Author Share Posted August 10, 2010 And little update... Managed to get new TPS-sensor here on forum. Changed the new sensor on the car and adjusted it. There was absolutely no change on the idle. Still bad as before. Still I can get best idle to put the tps-sensor to far right extreme position. If I turn the tps-sensor to far left extreme position the car is very close to stall. Also... Fiddled with MAP-sensor. If I keep car running and remove the vacuum pipe from the map-sensor should the car stall immediately? Quote Link to comment Share on other sites More sharing options...
Ian C Posted August 11, 2010 Share Posted August 11, 2010 That "winding tps on about 90 degrees" got me thinking and today I had to check how does the mechanism really work. It's been years since I had a proper look at them as well, so unfortunately your descriptions of position and directions are lost on me, especially while I'm sat at work miles away from my car Still. Measuring E2-IDL pins I only can get 0 or Infinite-reading on Ohm meter and the best position for TPS-sensor is far right (full throttle). That position makes car idle like on the video. Every other position will make idle worse. That reading is correct, it's the idle switch, so a simple on (0 ohm) or off (infinite ohms) for the ECU to know if it should be in idle mode or not. Also tried following method. I kept car running and turned the TPS-sensor slowly. Every millimeter from extreme right position to left made the idle worse. This is because you are sending the ECU an ever-increasing throttle position signal without it actually opening for real, guaranteed to confuse it, plus it no longer thinks you're idling as well. Fiddled with MAP-sensor. If I keep car running and remove the vacuum pipe from the map-sensor should the car stall immediately? Yes, the MAP sensor reports to the ECU that you are at atmospheric pressure, i.e. full throttle but no booost yet. It fuels for that but you're relly at about -8psi vacuum so it overfuels and stalls. It's at the point now where you need to know exactly what your fuelling is doing. That means measuring the pulse duration of the injectors somehow - easy with an E-Manage or aftermarket ECU, tricky without. An oscilloscope is the only way really but they aren't standard garage equipment... Quote Link to comment Share on other sites More sharing options...
FlrSupra Posted August 17, 2010 Author Share Posted August 17, 2010 Little update. Tried new MAP-sensor. No cure. Quote Link to comment Share on other sites More sharing options...
Fitz Posted August 17, 2010 Share Posted August 17, 2010 My N/A normally does that but only when I'm low on petrol, other than than she'll idle circa 750rpm on a cold start up around 1k rpm Quote Link to comment Share on other sites More sharing options...
FlrSupra Posted August 19, 2010 Author Share Posted August 19, 2010 So... After all this fighting and sh*t I decided to let the car go and I returned it to store and changed it to another car. They will solve the idle problem and promised to tell me what was wrong with it. So if lucky, the answer will be posted here later on. Thank you all for your kind and professional help!! Quote Link to comment Share on other sites More sharing options...
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