2JZ-GTE engine hunting at idle - conversion into falcon

[wrench]

Hey all, finally got the 2JZ into the XE started and running. I need to have the throttle open a bit to get it started, but once the engine gets warm it starts to hunt. I have sprayed aerostart and shellite all over the manifolds and all over the engine bay, its not a air leak. All vacuum lines are present and accounted for, all hose clamps are tight. I have disconnected a lot of stuff from the engine so i'm suspecting something has gone wrong there. It is in a XE falcon so i have gotten rid of the air con, power steer, hydraulic fan and so on. Not using traction control or ABS either. I pulled the ENTIRE wiring loom from my JZS147 aristo and put it in the falcon so i'm not short any wires, unless something is still connected that shouldn't be. Any ideas ????

[CELICASUPRA7M]

can you get codes from ECU?

[wrench]

Well all the diagnostic connectors are still there, but i don't have a scan tool lol. Also i forgot to mention, the fuel pump runs completely independantly so its getting fuel just fine. Its wired up to a switch from the battery.

[CELICASUPRA7M]

there should be a more basic way to get codes with a test light, also might be worth checking fuel pressure with a guage

[Shakotan_Aaron]

did you power up the idel control valve and VSV's?

mine would run at a high idle (maybe 2500rpm) then after it would hunt for idel after about 30sec-1minute when i was figuring out what needed what.

E3 (DLC1- +B) needs 12v when main relay is on.



Also see then COR thread to rectify the fuel pump control issue, you shouldn't have it running by a switch or when they key is on for safety reasons.

[wrench]

Where is the idle control valve on the engine? I didn't unplug any of the original engine loom except the 2 plugs at the ecu and they are obviously re-connected. I cut the 1/2 cut to pieces with the plasma cutter to ensure i didn't have to cut wires or unplug too much. The car is a drag car, i have the switch on the dash in front of me plus a battery cut switch at the rear of the car, this complies with ANDRA specs. The only computers i have unplugged is for the ABS, TRC, shock absorbers and airbags.

[wrench]

Also what is VSV??? yes that does sound like what mine is doing.

[Shakotan_Aaron]

did you see the picture? that engine>body plug has the pin that needs power.

these would of also been a fuel pump computer on the aristo originally to control the fuel pump.

idle speed control valve is on the head side towards the back of the intake manifold, has a pipe that runs along the back of the head to the intake manifold. VSVs control the sequential turbos etc.

that maybe so but id prefer the fuel pump to shut off strait away in the event of a crash, as soon as the engine is stalled the computer will shut off the pump.

[wrench]

So what if that wire already has power? I will check it tomorrow. Well i still have all the old modules and bits and pieces still here, i haven't thrown anything out. I can just go and re-plug everything back in that i unplugged.
Failing that, will un-plugging the idle speed control valve stop the hunting?
Yes i was also looking at fitting a inertia switch to the fuel pump too, but i'm more concerned with how the car is running firstly.
The car revs out fine too, just hunting idle.

[2jzhilux]

Check the tps adjustment.

[midnight_purple_GA70]

the fact that you had to crack the throttle a little to get it to idle at all suggests the idle control valve isnt working...

so ide look at that in a 1st instance...

hunting could be due to a number of things but at idle the stock aristo setup will only give the fuel pump 9v and you are giving it 12v... could be just a case of too much fuel at idle

[wrench]

I have a air fuel ratio gauge hooked up and at idle it says stoich. I though excess fuel would be returned to the tank via return line. I'm not after a perfect idle, just don't want the damn thing to hunt, i have a 3000 rpm stall in it so if it is hunting it will make it start to bunny hop a bit i think lol. Yeah i will check all these things out, will start by disconnecting IAC valve.

[wrench]

Disconnected IAC valve, made no difference, still hunting.
That EBD3 terminal has no power, do i induce 12V here as a fix?
There is also no seperate fuel computer from what i've been looking through, just the ECU.

[Shakotan_Aaron]

If ISCV isnt connected or powered it wont be able to idle or start normally.

When you shut the motor off the valve opens so that when you start it, it starts easy. similar to if you had of started it with 10% throttle. This is why its important to have it connected to +B not just the ignition. If it doesnt have power for another 2seconds or so after the engine is shut off it wont be able to reset for starting.

You could also check that its not blocked, not normally such a problem on 2jz from what ive seen but it can happen.

Im not sure about JZ motors but on 4ag's when the TPS wears out and dies they do the hunting.

[wrench]

Yeah i disconnected the TPS for testing sake, it idle ok but was over fueling like crazy.
I tried ignition on, starting and engine running and got no power at that terminal. So how do i fix this problem? Where do i source power from?