2JZGE Na-T TT Ecu Mod
04-11-15, 01:50 PM
#2521
Ali here's what I found to set the idle down but its weird. before start has the idle air screw pretty much all the way our, idle screw on the throttle cable portion down mostly and the tps full CCW.
Basically it was just high idling all the way to warm and stayed high, I kept backing out the idle air screw and nothing happened. So to get the idle down I screwed in the idle air screw until it idled up. Held it there for around 3 seconds and screwed it back out about 1-1 1/2 turns and it idled down to around 750 smooth. I have to wait for it to cool down and restart it to see if it holds otherwise the air screw just needs to be set further out.
Basically it was just high idling all the way to warm and stayed high, I kept backing out the idle air screw and nothing happened. So to get the idle down I screwed in the idle air screw until it idled up. Held it there for around 3 seconds and screwed it back out about 1-1 1/2 turns and it idled down to around 750 smooth. I have to wait for it to cool down and restart it to see if it holds otherwise the air screw just needs to be set further out.
04-12-15, 08:40 PM
#2522
thanks for posting the pics up, that should get people started in the right direction with the gte auto trans. only looks like a few connectors to tackle, pretty nice friend you have to help you with that.
are you using the US ecu? if you are using the jdm one and its a code 31 that means map sensor.
187, yeah it sounds like you are pretty much there keep it like that for a couple drives and then you will see where it settles, 750 is pretty close to where you want it normally it will idle down to 650 which I think is too low.
what I have noticed is when you shut it down the IACV goes to engine start position which is mostly open, and when you reset the ecu it will start here and it wont go down a bunch till the ecu decides its time to start learning stuff again.
usually you can't tell what adjustment you have done until its at least warmed up for like 15 min and then it randomly decide to idle down, and if you have the screw set right it will only be able to idle down to 800 ish.
if it can get down to 650 try another half turn on the screw and repeat. it takes a while, I make very small adjustments every couple drives and once you hit that spot you just never move it until you have to again.
are you using the US ecu? if you are using the jdm one and its a code 31 that means map sensor.
187, yeah it sounds like you are pretty much there keep it like that for a couple drives and then you will see where it settles, 750 is pretty close to where you want it normally it will idle down to 650 which I think is too low.
what I have noticed is when you shut it down the IACV goes to engine start position which is mostly open, and when you reset the ecu it will start here and it wont go down a bunch till the ecu decides its time to start learning stuff again.
usually you can't tell what adjustment you have done until its at least warmed up for like 15 min and then it randomly decide to idle down, and if you have the screw set right it will only be able to idle down to 800 ish.
if it can get down to 650 try another half turn on the screw and repeat. it takes a while, I make very small adjustments every couple drives and once you hit that spot you just never move it until you have to again.
Last edited by Ali SC3; 04-12-15 at 08:47 PM.
04-13-15, 03:36 PM
#2523
That 15 min gap seems to be pretty annoying. The next day I let it idle long enough for it to throw a cel even though I know it was working in that exact position. Really at a loss here. All I can do is back it out more but once the idle goes down but it doesn't seem to matter. What ever its learning seems to be only a trick that gets lost when the car sits long enough to cool down.
Other wise its been running the best it has been yet. I've even been considering putting in my boost controller since it is doing so well at 6 psi. I want to log the timing to check on it before I do but I really need to get this tps thing behind me so I can enjoy the car.
Other wise its been running the best it has been yet. I've even been considering putting in my boost controller since it is doing so well at 6 psi. I want to log the timing to check on it before I do but I really need to get this tps thing behind me so I can enjoy the car.
04-14-15, 09:15 AM
#2524
if it can idle back down to 650, then you still need to turn in the screw more. one time, hopefully in the near future, when you do it, the ecu will only be able to idle down to 800 ish.
each time you push it in a little more, the ecu has to use a lower IACV position to lower the idle back down (ut it only tries this after like 15 minutes if you are lucky).
after a couple of very boring times of repeating this it will bottom out in the lowest position, and thats when the 800 can be set.
its not easy and takes me several tries to set the idle myself as its complete trial and error to find where the IACV bottoms out.
I leave my tps backed off most of the way so when I make these adjustments I don't have to mess with the tps after, I think that would be all the way counter clockwise on the stock setup or position with lowest tps %.
each time you push it in a little more, the ecu has to use a lower IACV position to lower the idle back down (ut it only tries this after like 15 minutes if you are lucky).
after a couple of very boring times of repeating this it will bottom out in the lowest position, and thats when the 800 can be set.
its not easy and takes me several tries to set the idle myself as its complete trial and error to find where the IACV bottoms out.
I leave my tps backed off most of the way so when I make these adjustments I don't have to mess with the tps after, I think that would be all the way counter clockwise on the stock setup or position with lowest tps %.
04-14-15, 02:24 PM
#2526
I dont think you are understanding me right, at no point will you be able to set it and see that it worked right away.
you have to make the adjustment, drive it around a few times, then see where it is. if its at 650 still, then turn in the screw 1/2 turn more, reset the ecu, and drive it around a few times and see where it is. if it goes back to 650 again then just repeat. After a few times the next 1/2 turn you do then reset then a few drives it will try and idle down but will not be able to go lower than 800. got it?
when its at 650 and you adjust it a half turn you cannot go off of what it is then, you have to reset it and drive it around.
Even if the coolant temp is already warm the ecu is programmed not to learn anything for a few cycles, you can either wait it out or just do a few drives.
the ecu will always try to idle at 650 after it starts learning, and if the idle is higher by you turning the screw after it starts learning it will try to lower the IACV position to achieve that 650 again. this is why you can have it at 650, turn it in a half time, reset the ecu and still have it go back to 650, it just lowered the IACV position some. you need to repeat till it cannot lower the iacv anymore as in its in the lowest position.
so if its at 650, the screw is not in enough to help with your problem you are still in the range of what the IACV can adjust so essentially its not doing anything.
I can't say though that once you get it to idle at 800 that the tps will still be in range cause you will have to turn in the screw several times opening up the throttle plate. I am not sure how far the factory slots can compensate, but the more the screw is turned in, that is more air entering the motor that the ecu cannot subtract and is the only way to bump up the idle some without the IACV compensating. its a tough balance but one could slot the tps and get more adjustment out of it if that is the case.
either that or you can disconnect the IACV and set the idle and it will never change, but you will have to have your foot on the gas while it warms up for the first 30-45 seconds.
you have to make the adjustment, drive it around a few times, then see where it is. if its at 650 still, then turn in the screw 1/2 turn more, reset the ecu, and drive it around a few times and see where it is. if it goes back to 650 again then just repeat. After a few times the next 1/2 turn you do then reset then a few drives it will try and idle down but will not be able to go lower than 800. got it?
when its at 650 and you adjust it a half turn you cannot go off of what it is then, you have to reset it and drive it around.
Even if the coolant temp is already warm the ecu is programmed not to learn anything for a few cycles, you can either wait it out or just do a few drives.
the ecu will always try to idle at 650 after it starts learning, and if the idle is higher by you turning the screw after it starts learning it will try to lower the IACV position to achieve that 650 again. this is why you can have it at 650, turn it in a half time, reset the ecu and still have it go back to 650, it just lowered the IACV position some. you need to repeat till it cannot lower the iacv anymore as in its in the lowest position.
so if its at 650, the screw is not in enough to help with your problem you are still in the range of what the IACV can adjust so essentially its not doing anything.
I can't say though that once you get it to idle at 800 that the tps will still be in range cause you will have to turn in the screw several times opening up the throttle plate. I am not sure how far the factory slots can compensate, but the more the screw is turned in, that is more air entering the motor that the ecu cannot subtract and is the only way to bump up the idle some without the IACV compensating. its a tough balance but one could slot the tps and get more adjustment out of it if that is the case.
either that or you can disconnect the IACV and set the idle and it will never change, but you will have to have your foot on the gas while it warms up for the first 30-45 seconds.
Last edited by Ali SC3; 04-14-15 at 02:28 PM.
04-14-15, 03:57 PM
#2527
Alright I'll give it a try this weekend probably. Thanks for the explanation 
, I had no idea what the IACV has been trying to do this whole time.
I think the tps should be alright, the air screw can go pretty far in before tripping it up since I'm all the way CCW.
, I had no idea what the IACV has been trying to do this whole time. I think the tps should be alright, the air screw can go pretty far in before tripping it up since I'm all the way CCW.
04-14-15, 07:30 PM
#2528
I dont think you are understanding me right, at no point will you be able to set it and see that it worked right away.
you have to make the adjustment, drive it around a few times, then see where it is. if its at 650 still, then turn in the screw 1/2 turn more, reset the ecu, and drive it around a few times and see where it is. if it goes back to 650 again then just repeat. After a few times the next 1/2 turn you do then reset then a few drives it will try and idle down but will not be able to go lower than 800. got it?
when its at 650 and you adjust it a half turn you cannot go off of what it is then, you have to reset it and drive it around.
Even if the coolant temp is already warm the ecu is programmed not to learn anything for a few cycles, you can either wait it out or just do a few drives.
the ecu will always try to idle at 650 after it starts learning, and if the idle is higher by you turning the screw after it starts learning it will try to lower the IACV position to achieve that 650 again. this is why you can have it at 650, turn it in a half time, reset the ecu and still have it go back to 650, it just lowered the IACV position some. you need to repeat till it cannot lower the iacv anymore as in its in the lowest position.
so if its at 650, the screw is not in enough to help with your problem you are still in the range of what the IACV can adjust so essentially its not doing anything.
I can't say though that once you get it to idle at 800 that the tps will still be in range cause you will have to turn in the screw several times opening up the throttle plate. I am not sure how far the factory slots can compensate, but the more the screw is turned in, that is more air entering the motor that the ecu cannot subtract and is the only way to bump up the idle some without the IACV compensating. its a tough balance but one could slot the tps and get more adjustment out of it if that is the case.
either that or you can disconnect the IACV and set the idle and it will never change, but you will have to have your foot on the gas while it warms up for the first 30-45 seconds.
you have to make the adjustment, drive it around a few times, then see where it is. if its at 650 still, then turn in the screw 1/2 turn more, reset the ecu, and drive it around a few times and see where it is. if it goes back to 650 again then just repeat. After a few times the next 1/2 turn you do then reset then a few drives it will try and idle down but will not be able to go lower than 800. got it?
when its at 650 and you adjust it a half turn you cannot go off of what it is then, you have to reset it and drive it around.
Even if the coolant temp is already warm the ecu is programmed not to learn anything for a few cycles, you can either wait it out or just do a few drives.
the ecu will always try to idle at 650 after it starts learning, and if the idle is higher by you turning the screw after it starts learning it will try to lower the IACV position to achieve that 650 again. this is why you can have it at 650, turn it in a half time, reset the ecu and still have it go back to 650, it just lowered the IACV position some. you need to repeat till it cannot lower the iacv anymore as in its in the lowest position.
so if its at 650, the screw is not in enough to help with your problem you are still in the range of what the IACV can adjust so essentially its not doing anything.
I can't say though that once you get it to idle at 800 that the tps will still be in range cause you will have to turn in the screw several times opening up the throttle plate. I am not sure how far the factory slots can compensate, but the more the screw is turned in, that is more air entering the motor that the ecu cannot subtract and is the only way to bump up the idle some without the IACV compensating. its a tough balance but one could slot the tps and get more adjustment out of it if that is the case.
either that or you can disconnect the IACV and set the idle and it will never change, but you will have to have your foot on the gas while it warms up for the first 30-45 seconds.
04-15-15, 08:17 AM
#2529
thats good news then if it is happy with 800 cause that is where I have found it to work best at fir driving around. the power steering seems to get strained at 650 when turning, at 800 there are no wierd noises for me.
another old school trick is drilling a small hole in the throttle plate, but that is not reversible.
another old school trick is drilling a small hole in the throttle plate, but that is not reversible.
04-19-15, 11:35 AM
#2530
Well I set it as we discussed, it takes a while to idle down but it settles now at about 800-900 rpms. The only thing is during that warm up period I'm getting misfire codes until it idles down. I'm not sure if they will set if I keep driving I'll have to wait on that one.
Somehow I'm still getting a p1658, I had it tapped in with the other vsv's and it was an issue still so I connected the pin to ground with the proper resistor in between and it still came back. Eventually the code will set and then no boost.
Somehow I'm still getting a p1658, I had it tapped in with the other vsv's and it was an issue still so I connected the pin to ground with the proper resistor in between and it still came back. Eventually the code will set and then no boost.
04-21-15, 09:34 AM
#2531
maybe for obd2 it would be easier to just plug in a vsv for that one but there should be a resistor that does the trick. maybe a different value is needed.
see if it clears up maybe it just has to learn for a bit. if its still getting misfires it may be that it is set too high for the tps. if the tps is maxed out, then maybe back the idle screw off a hair. 700-800 is enough to do the trick if that is the case.
see if it clears up maybe it just has to learn for a bit. if its still getting misfires it may be that it is set too high for the tps. if the tps is maxed out, then maybe back the idle screw off a hair. 700-800 is enough to do the trick if that is the case.
04-21-15, 02:30 PM
#2532
The problem with the misfires is that 15 minute learn period. Does that ever go away?
I had it tapped into one of the other vsv's I think the only one there was the vsv for the intake valve. It solved the other codes but for some reason pin 60 isn't the same.
I followed the guide from the supra's. The plug on the supra is just the same thing from pin 60 to ground right? Do I need to add more resistance to make up for the missing wire length or something?
I had it tapped into one of the other vsv's I think the only one there was the vsv for the intake valve. It solved the other codes but for some reason pin 60 isn't the same.
I followed the guide from the supra's. The plug on the supra is just the same thing from pin 60 to ground right? Do I need to add more resistance to make up for the missing wire length or something?
04-21-15, 09:11 PM
#2535
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My ecu/cop swap is still running great as NA, but as I start to collect parts for the turbo kit I'm doing bits as I can along the way. I'm thinking of getting the xs power ffim and getting that working first to clean the engine bay up. For those that went that route what did you do for throttle body and tps and IAC?