Idle surge

[PSIBRG]

Ok, started doing it again. Seems to pop up after I floor it/get some rpm into it. And then won't go away.

Sick of this shit

[speedracer_nz]

I will have a look around my garage but i think i have one or 2 complete throttle body assemblies kicking around that I can donate to your cause. Have you checked your throttle blade itself for cracks or gaps, what about the throttle stop. the throttle isn't opening up under vacumn is it from a faulty spring etc. I will have a look at my throttle body and see how you could go about deleting the idle speed control just to test a theory. I hate those faults that come and go like that!!!!

[Looonie]

Heya Rah,

When I pulled the runners off for you, theres also a heap of vacuum lines and a vacuum chamber and stuff underneath the runners, probably something to do with that high RPM surge we discussed.

Perhaps faulty valve or blocked line in that setup? Welcome to grab the old gear I've still got here if you want it. Although hard to believe 240k+ stuff would be any better than the nearer 100k stuff thats on there.

[PSIBRG]

I will have a look around my garage but i think i have one or 2 complete throttle body assemblies kicking around that I can donate to your cause. Have you checked your throttle blade itself for cracks or gaps, what about the throttle stop. the throttle isn't opening up under vacumn is it from a faulty spring etc. I will have a look at my throttle body and see how you could go about deleting the idle speed control just to test a theory. I hate those faults that come and go like that!!!!

That'd be awesome man. Got a non traction-control throttle body? Will happily give you a bit of coin for one if you do
Yup i've checked the throttle plate, it was a bit gunked up the first time I pulled the throttle body off but it cleaned up fine, no cracks or gaps. Throttle stop is sweet too.

One thing I have noticed is that even though the throttle spring is sweet when the throttle body is off the car (throttle plate returns to closed position as it should), when it's on the car and the throttle cable is hooked up to it, it doesn't actually close all the way when moving it by hand. It's like the cable is binding on it's casing somewhere. I've tried to free it up a bit but no success so far.

However in saying this, while the idle is playing up, even if I force the throttle plate closed, the idle still won't drop. So although the binding cable is an issue in itself, I think it's unrelated.

Bit more info...

The RPM doesn't surge anymore (hasn't done this ever since I replaced the TPS), just maintains a steady high idle. Before I pulled the throttle body off for the first time, the surging occured ONLY when the car was started while already warm. On a cold start it'd be sweet, and would drive sweet up until the time when I turn the car off and re-start it.

As it sits now, the problem is constant, happens when cold/warm/whatever. If I pull the TPS and ISCV off again and put them back on, the issue will disappear. Until I floor it and get the rpm's up to near redline, and then the problem will show it's face again.

It's a weird one that's for sure!

[PSIBRG]

Heya Rah,

When I pulled the runners off for you, theres also a heap of vacuum lines and a vacuum chamber and stuff underneath the runners, probably something to do with that high RPM surge we discussed.

Perhaps faulty valve or blocked line in that setup? Welcome to grab the old gear I've still got here if you want it. Although hard to believe 240k+ stuff would be any better than the nearer 100k stuff thats on there.

Hey man,

From what i've seen while working on the motor, those vac lines and chamber etc are for the variable intake (hence why it has that 'kick', and the intake sound changes at 4500rpm). It looks like it has a similar setup to the intake manifold that I used to run on my Mirage - which had 8 runners, 2 per cylinder, below 4100rpm it only ran 4 runners for increased intake velocity, and then once you hit 4100rpm it opened up all 8 runners for max flow. It had the same kinda vac chamber setup as the 2JZ.

That particular function seems to be working fine so I don't think it's a cause of the problem. Will keep it in mind though!

[speedracer_nz]

hey I have a complete non traction control throttle body here with all the sensors if you need it. I know it all goes fine for a fact. 021 150 8774 txt me if you wanna come get it im in west auckland