Guest Grim-91 Posted April 8, 2016 Share Posted April 8, 2016 Hey everyone first of all if this is posted in the wrong place I apologize this is my first forum. Recently my Toyota Supra, 1993, 2JZ-GE, 5 speed manual has been stalling while idling and the accelerator stops responding if the car is in motion. This only happens when the air conditioner is on and set to cold. At first the accelerator stopped responding and that was the only issue so I replaced the TPS (Throttle Position Sensor) as I had read that it can be the cause of that it didn't solve the problem. About 2 weeks after the accelerator issue started the idle issue started when sitting the car would constantly go to stall some times the revs go back up but sometimes it does stall. I replaced the IACV (Idle Air Control Valve) but still the issues continue. I have tried holding the revs at 4000 and turning the aircon on and it still goes to stall. I have disconnected the compressor on the air conditioning system and it still goes to stall. I have spoken to several mechanics an air conditioning specialist and I have had an auto electrician out to diagnose the car and still nothing it didn't come up with any error codes the car was running fine according to his computer even though it was trying to stall while he was doing the tests. I am down to very few ideas I am going to pull the ECU out and see if anything looks bad with it but without another one to test it with there is no real way of knowing for sure if its the problem without buying a new one, other than that my only other idea is to take it back to the air conditioning specialist as I am sure that the problem has something to do with that. The car runs perfectly with the aircon off. If anyone has had this issue before or has any ideas any and all help is appreciated and if anyone needs any extra information I will try my best to get it to you asap Thanks. Quote Link to comment Share on other sites More sharing options...
np89 Posted April 8, 2016 Share Posted April 8, 2016 Could be the alternator on the way out, Aircon places a heavy load on the system Quote Link to comment Share on other sites More sharing options...
Guest Grim-91 Posted April 8, 2016 Share Posted April 8, 2016 Sorry I forgot to say that I have checked the alternator it is working fine. Quote Link to comment Share on other sites More sharing options...
Scooter Posted April 8, 2016 Share Posted April 8, 2016 I have disconnected the compressor on the air conditioning system and it still goes to stall. The car runs perfectly with the aircon off. these two statements would seem to contradict each other? I would remove your aux belt and check each pulley for good freedom of movement and also check your speedo convertor if you have one as they can do funny things - but usually throw an error code. There is a butterfly valve in the y pipe that may not be operating smoothly.....these are just things stuck in my head from old threads or personal experience i'll try to find some similar threads. Quote Link to comment Share on other sites More sharing options...
Scooter Posted April 8, 2016 Share Posted April 8, 2016 some good info here? http://www.mkivsupra.net/vbb/showthread.php?327650-Constant-Stalling-Issue-Frusrtated&highlight=stalling+idle Quote Link to comment Share on other sites More sharing options...
Guest Grim-91 Posted April 8, 2016 Share Posted April 8, 2016 I don't really know why turning the aircon on with the compressor unplugged still causes it to stall just put that part in there as it rules out the compressor the pulley on the compressor feels fine and the air conditioner specialist said it was fine. I will have a look at the butterfly valve see if it working alright and as for the speedo converter I have already had that issue and dealt with it so don't think it would be that. Thanks for all the quick responses I wasn't expecting this many replies so soon. Quote Link to comment Share on other sites More sharing options...
Mike2JZ Posted April 8, 2016 Share Posted April 8, 2016 When you replaced the TPS did you use a multimeter to calibrate the TPS into factory position? Would you be able to take a video of the behavior you explained above, or at least explain a little better how the car stalls. Does the engine shut off, but dash lights remain or does the whole car die? Is it instant stall, or slowly dies? There is a vsv on the firewall that has to do with the AC. Try checking for vaccum leaks on it, or disconnect it completely to see what effect it has on the car, and if you can get the vsv to work off the car (check TSRM if there is a maintenance procedure for this?) Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted April 8, 2016 Share Posted April 8, 2016 (edited) If the engine literally stops whatever RPM are showing every time you turn the air con on and the connector at the compressor is removed I would call an ecu fault. the air con clutch signal is ecu generated, it also calls for an idle up condition, i think, via the air bleed near the PAS pump. Try disconnecting that too. I can only think something has happened within the ecu itself that's killing a vital engine function when it should only be calling for the air con clutch to engage and for an idle up. You could try cutting the a/c signal wire and the idle up signal wire near the ecu and see what happens, but I would guess it's internal. Never come across something like this before, not spilt a case or two of Fosters in the footwell have you? Even a quite major vac leak wouldn't cause this, and a hose off a VSV will only cause a pretty minor one. Edited April 8, 2016 by Chris Wilson (see edit history) Quote Link to comment Share on other sites More sharing options...
Guest Grim-91 Posted April 9, 2016 Share Posted April 9, 2016 Dash lights stay on just the engine dies and thats if it doesn't save itself sometimes the idle goes back up. It happens pretty quickly a few seconds and it has stalled or gone back to idling normally and also it is not consistent sometimes it will do it on a cold start and not as much when hot sometimes it wont do it at all when the car is cold but once it gets up to temperature it is going to stall. Sometimes the gaps between stalling are 10-20 seconds sometimes its 1-5 minutes the only consistency is that its only when the aircon is on. I am going to go through and check everything that has been suggested so far just to be safe. I will let you know how it goes and please keep the ideas flowing. thanks again for all the help. Quote Link to comment Share on other sites More sharing options...
Scooter Posted April 9, 2016 Share Posted April 9, 2016 Chris is very knowledgeable so I would beg borrow or buy a ecu of your type to try. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted April 9, 2016 Share Posted April 9, 2016 You need to clarify this question: If you are driving along at say 30 MPH and you turn the air con on, does the engine stop? That is what you seemed to be saying earlier. Quote Link to comment Share on other sites More sharing options...
Guest Grim-91 Posted May 19, 2016 Share Posted May 19, 2016 Sorry it has taken me so long to do this things have been really busy lately. I have pulled apart the ECU and a capacitor has leaked onto the board it looks like it can be repaired and I have a friend that can do it he is asking for a schematic of the ECU would anyone have a copy of this or know of I site I could get this? I have tried uploading pictures but it wont let me I will post the details as best I can. *1757004771$* Engine Control Toyota 89661-14610 175700-4771 12V 2JZ-GE M/T If I am travelling at 30MPH and turn the aircon on the engine doesn't stop the accelerator stops responding I will have my foot flat to the floor and it is as if I'm not touching it at all if I am idling however the the engine stalls. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 19, 2016 Share Posted May 19, 2016 You will not find an ecu shematic I'm afraid unless you are REALLY pally with a bent insider at Toyota. They don't release stuff like that! Quote Link to comment Share on other sites More sharing options...
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