Well this has been going on with my car since I got it and I need to fix it. I'll start it, it will run and idle fine, but then when it warms up the idle just gets worse as time goes on. It will start to sputter and almost die, but then catch up and keep going. I've read a little and it sounds like it might be a boost leak, but I just replaced my IC piping to hardpipes and still all the same. Its actually like somewhat of a violent sputter too. It shakes the engine a bit. I'll probably go out and clean the ISC and adjust the TPS, but any other things you guys could think of off hand? The main thing that puzzles me is that its only a crappy idle AFTER its warmed up.
Bad idle when warmed up
- Thread starter Back2Basics
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There is a negative temperature coefficient sensor in the cooling system (ECT). The circuit needs to be working correctly for the ECU to make the correct choices. You could also have a component failure, but after you check the circuit controlling it, then you can worry about it.
So what exactly is the term I should be searching and looking for? All I got for ECT was electronic controlled transmission or close to that. I looked in the tsrm at the cooling and electrical diagram systems, but couldnt find anything either. I really dont know what else to go off of from what you said.
do you have an EGR on the car? if you do it could be your egr, thats stuck open during idle. This happen to me. Car would warm up at 650 rpm and then drop to 400 and it would idle all crazy and then die.
Actually I just removed it all during this IC piping project....and its still doing the same thing it was before I did any work on it.
bump, somebody has to know by now. there were a bunch of threads talking about this type of problem, but there was never a confirmed solution to it.
Last time I checked there was a code 31. I know thats the AFM, but I thought that if you had a faulty AFM, then the engine would run the same as if you had it unplugged. And actually when I went to start it up the first time after doing all my IC pipe work, I forgot to plug in the AFM sensor and the car wouldnt start up and run. When I plugged it in, then it ran. So shouldnt that technically mean that the AFM is okay yet?
Tomorrow I will check for codes again and post up the results.
Edit: How much would the idle be affected without an air filter on the AFM?
Tomorrow I will check for codes again and post up the results.
Edit: How much would the idle be affected without an air filter on the AFM?
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I just checked and now im not throwing any codes. i took my afm off and the adjustment screw was in almost all the way. where is it suppose to be at for the stock location? my mods are 2.5" hard pipes, 3"dp, but 2.5 the rest of the way, oem hg w/ arps, 3" hks intake adapter w/ cone filter. i'd also think that my afm isnt bad since there are no codes.
That is a definite possibility. I know some of my plugs around there arent the most secure. That might be one of them. Is there any information on it in the tsrm because I couldnt find anything? I searched and found a little info on it and it seems as though that could and hopefully is my problem. Is it usually just the sensor that goes bad? I'd hate to have the wiring or plug itself be messed up.
So, you are finally ready to check the ECT circuit? If you look at the EWD, the signal will be on the THW wire, which is themal water.
lol yes I am.....as you stated I should do before. what exactly does ECT stand for? I came back to school yesterday so I'll have to wait until this weekend when I go back to the city my car is in.
engine coolant temp.
With a warm engine, disconnect the sensor. You should get a code set and the ECU will default to 80deg C. It should run okay warmed up with that default temp.
With a warm engine, disconnect the sensor. You should get a code set and the ECU will default to 80deg C. It should run okay warmed up with that default temp.
:1zhelp: Hey! I've had this same exact problem ever since owning my supra turbo...
i think it might be the same thing sounds very similar...
anyway, where do i find the EGR valve and the Coolent temp sensor?
What do i do if its the EGR getting stuck open? lube it or replace it or what?
thanks
adam
i think it might be the same thing sounds very similar...
anyway, where do i find the EGR valve and the Coolent temp sensor?
What do i do if its the EGR getting stuck open? lube it or replace it or what?
thanks
adam
haven't had to worry about this with the Supra, but on my MR2s the cold idle is almost 2k RPMs. As it warms it drops to 800 RPMs.
The Supra is no exception. All fuel injected Toyotas that I've been in do this, maybe not at 2k, but they all have a high cold idle to expedite the warm-up.
If someone didn't know this, and they used the idle adjustment to counter computer control and bring cold idle down to ~600 (Supra idle speed IIRC), then the system can bring the idle down too far to idle at all after warm-up.
Double-check your idle adjustment, quick and easy.
The Supra is no exception. All fuel injected Toyotas that I've been in do this, maybe not at 2k, but they all have a high cold idle to expedite the warm-up.
If someone didn't know this, and they used the idle adjustment to counter computer control and bring cold idle down to ~600 (Supra idle speed IIRC), then the system can bring the idle down too far to idle at all after warm-up.
Double-check your idle adjustment, quick and easy.
idle adjustment is the adjustment screw on the afm correct? or would that mean to adjust the tps?
my afm adjustment screw was like 7/8 of the way closed and I didnt think that was right so I looked online and found a few pictures with the screw halfway. is this correct?
my afm adjustment screw was like 7/8 of the way closed and I didnt think that was right so I looked online and found a few pictures with the screw halfway. is this correct?
The screw on the AFM is to adjust fuel mixture. IDK what it should be opened to, but there should be an aluminum plug blocking the adjustment screw from the factory to prevent adjustment. If that is too far closed, you will run rich at idle.
I haven't had to mess with this on my Supra, but on my MR2s, the idle adjustment screw is on the throttle body under a rubber cap. It is the same on my 4A-GE and 4A-GZE. I would assume the Supra has a similar adjustment, but am not certain.
Do not mess with the TPS to adjust idle. But if the TPS is already out of adjustment, it can cause idle difficulty as well. If you have a Toyota repair manual, and you suspect TPS troubles, there should be a testing procedure in it.
I haven't had to mess with this on my Supra, but on my MR2s, the idle adjustment screw is on the throttle body under a rubber cap. It is the same on my 4A-GE and 4A-GZE. I would assume the Supra has a similar adjustment, but am not certain.
Do not mess with the TPS to adjust idle. But if the TPS is already out of adjustment, it can cause idle difficulty as well. If you have a Toyota repair manual, and you suspect TPS troubles, there should be a testing procedure in it.
Thanks for all the info 86mister2!
I looked through the TEWD section for the ECT, but couldnt find anything with THW. How do I actually "test the circuit"?
Nick M said:
I looked through the TEWD section for the ECT, but couldnt find anything with THW. How do I actually "test the circuit"?
If JJ sees this thread there is going to be trouble.... :biglaugh:
Here is the diagnostics for the coolant sensor. You couldn't have looked too hard.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&Page=113
Just for the record, the ECU will null out any adjustments to the throttle air bypass screw until it runs out of adjustment on the ISC valve. Since it is a closed loop idle speed control system, the target idle speed cannot be changed, unless you change the code in the ECU, which is nearly impossible without major ECU hardware mods. It does not affect mixture, as the idle is running closed loop with the oxygen sensor.
Here is the diagnostics for the coolant sensor. You couldn't have looked too hard.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&Page=113
Just for the record, the ECU will null out any adjustments to the throttle air bypass screw until it runs out of adjustment on the ISC valve. Since it is a closed loop idle speed control system, the target idle speed cannot be changed, unless you change the code in the ECU, which is nearly impossible without major ECU hardware mods. It does not affect mixture, as the idle is running closed loop with the oxygen sensor.