Odd Idle and Rev Problem 1jz

[supramk3man]

My 1jz started acting odd it wouldn't take gas and it would only start for a second and die. i check the cel and it was a code 14 so i took the ecu and sent it to Driftmotion. While waiting for it to come back i had gotten another ecu to use during the down time. well to day i start the car and it idles high around 1000 then it will start rasing up to 1700 and drop right back down and keep doing this. i unhooked the tps and it stoped jumping idle but then it would just idle around 2300 and do nothing else. i have alot of spare parts to swap around with but i don't know what to start with. the car is a every day driver and never has acted up before. any help would be great

[di_rosa]

try re-calibrating your tps.

usually code 14 means your car won't run, i guess check the resistance of your cam/crank sensors..........usually it's the cam sensor if your car will run, since the ecu knows one is shot, and it can choose to only accept input from the other "good" one. or your wiring is shot.

[supramk3man]

Would a bad ecu make a car idle this way. i don't have a cel light on it isn't showing any codes.

[supramk3man]

Any one got any thoughts

[Satan]

Hey man.. How ya been,

On my 2J, the idle fluctuates/bounces and I am sure that it's the IACv. Only bounces between 600-900 RPMS. I have another one I need to put on now, which should fix the issue.

You may be able to fit a 2J IACv on there, but it will not be very easy. The 1J's is a 1-piece bracket/stepping-motor and the 2J can come apart. The coolant tubes are also pointed/shaped differently.

I have a spare 1J IACv that I may be able to let go. Check your TPS again and PM me if you want the 1J IACv I have. I am not sure what other Toyotas may have ones that can work, but I did not find ANY for the 2J... even the 1J one does not work in it's place.

[supramk3man]

i have complete 1jz swap from another supra that i can swap parts from to test i just need to know what i need to start swaping to test.

[di_rosa]

ok, well swap the iac, and re-calibrate your tps.

[supramk3man]

Can a tps just out of no where get out of tune?

[tlo86]

Can a tps just out of no where get out of tune?

apparently:(

[supramk3man]

Well i will try to look in to it tonight i have another tps i can put on and i will change out the Iacv

[Dylan JZ]

doesnt sound like an ECU problem.. however, the first time around you were correct to send it off to aaron. That "it wouldn't take gas and it would only start for a second and die" condition is a tell tale sign.

IACV is likely on this other issue.

[supramk3man]

Just don't understand how a car can run so good and then out of no where the ecu go bad and now something else in less then a week.

[Dylan JZ]

Just don't understand how a car can run so good and then out of no where the ecu go bad and now something else in less then a week.

crazy huh? thats the question many ask themselves.

[supramk3man]

LoL i didn't get a chance to do any parts swaping last night so i will tonight and let you all know if it does change.

[OneJZsidzilla]

You know, on start up, I get a similar response, where it runs up at like 1200 for a few minutes, and once the engine warms up it comes back down to like 800...never really thought anything about it until this post

[supramk3man]

Well this car starts prefect and idles with out missing a beat so it was just really noticable to me.

[tylerjacobsen85]

I had to same problem on my car and it was the Iacv.

[supramk3man]

I hope the extra one i got is good i really hate having to drive the truck around and with gas at a all time high it isn't very handy

[Dylan JZ]

supra owner complaining about gas prices.. :squint: I understand though, I get great mileage out of my car.

[supramk3man]

The car gets around 28 the truck gets lucky 12-14 when you drive around 300-400 miles a week it hurts.

[supramk3man]

Well i changed out the Iacv and the car doesn't just rev up and down now but it still revs higher then normal by around 1000 rpm. Is there any way that the new ecu and my old tps just aren't reading each other like my old ecu. not sure that makes sense. Well what part should i check now, the car never had any problems before the ecu went out so i just don't understand how the TPS or the IAcv has went bad over night.

[supramk3man]

I just changed out TPS and no matter what you do moving it the idle doesn't go down so i'm thinking there maybe something not just right with the other ecu i have been using i will try to find out from Aaron when i should get my other one and will let you guys know what happens.

[tlo86]

supra owner complaining about gas prices.. :squint:

:biglaugh::biglaugh::biglaugh:

i get amazing gas mileage too. ive been on the same tank for the past 3 months and still halfway... maybe i should start driving it for once Lol

[supramk3man]

Good one

[supramk3man]

Just got my old ecu back in from Aaron and looks like the caps was all that was wrong so far "Knock on Wood". Other then the idle was a little high on other ecu the car was fine.

[Dylan JZ]

Just got my old ecu back in from Aaron and looks like the caps was all that was wrong so far "Knock on Wood". Other then the idle was a little high on other ecu the car was fine.

good for you man.. mine ended up being shorted out. he's still gonna see if he can fix it though.

[supramk3man]

I have the other one i was using i just put it on ebay, the car acted fine with it just had a high idle around 1400 rpm but it took gas great and seemed to be fine. the number on my ecu and that was a little different i think that it might by chance have been for a different series 1 1jz and my motor is series 2 if that would make a difference.