high idle... don't really know why

[crazysupra2JZ]

i finally got my engine running right, but it idles really high. it idles at 2000 rpms. the set screw is loosened all the way for the throttle and when i adust the TPS down all the way it idles from 1400 to 2000 rpms. just up and down. when i pinch the hose to the ISC and it idles at like 1000. never goes any lower than that. maybe there's a problem with the ISC and air supply to it, i don't know.

http://www.youtube.com/watch?v=S7wbyFLCOaU

http://www.youtube.com/watch?v=p90WhO1vevw​

http://www.youtube.com/watch?v=zDq_-K3FKVM​

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[suprastanger507mgte]

How do you have the ISC port hooked up? Most people put a filter there. If it is not covered by a filter or routed back into the intake piping ( air filter housing, your car will idle high. IF you completely block it, your car will stall.

 

[crazysupra2JZ]

How do you have the ISC port hooked up? Most people put a filter there. If it is not covered by a filter or routed back into the intake piping ( air filter housing, your car will idle high. IF you completely block it, your car will stall.

i have a V8 breather filter for a valve cover on it right now

 

[tlo86]

do you have the driftmotion p/s line? or is the VSV for it hooked up?

 

[jdub]

What ECU/EMS?

 

[crazysupra2JZ]

do you have the driftmotion p/s line? or is the VSV for it hooked up?

yes i do and i do not have the VSV for it. i don't see how you can put it on?

What ECU/EMS?

stock aristo ecu

 

[jdub]

stock aristo ecu

If it's like other TCCS (and I'll bet it is), the ISCV needs metered air to properly adjust idle...you should not use a filter unless you've switched to a speed density set-up. You want to check for vac leaks too.

 

[crazysupra2JZ]

If it's like other TCCS (and I'll bet it is), the ISCV needs metered air to properly adjust idle...you should not use a filter unless you've switched to a speed density set-up. You want to check for vac leaks too.

with no filter, it idles even higher. when i pinch it shut, it goes down to 1000rpms.

 

[jdub]

with no filter, it idles even higher. when i pinch it shut, it goes down to 1000rpms.

Considering the filter is a huge air leak, that's exactly what it should do. The air feed needs to be routed to the intake after the AFM. I am surprised it runs smoothly.

I'm betting he also have another vac leak somewhere. If you block off the ISCV and the PCV fitting on the TB, the motor should die. If it doesn't, you have another source of air that should not be there.

 

[crazysupra2JZ]

Considering the filter is a huge air leak, that's exactly what it should do. The air feed needs to be routed to the intake after the AFM. I am surprised it runs smoothly.

I'm betting he also have another vac leak somewhere. If you block off the ISCV and the PCV fitting on the TB, the motor should die. If it doesn't, you have another source of air that should not be there.

it's MAP based, so there's no meter before the intake. i just have a hose and a filter for the ISC, you can see the red hose in the videos

 

[jdub]

Where is the ISCV air source on the Aristo?

 

[OneJSupra]

check for vacuum leaks, my 1j idled at 1500rpm one day and couldn't figured out for a day till i found one of the vacuum hose was disconnected and after I zip tie the hose the idle went back to normal.

 

[crazysupra2JZ]

Where is the ISCV air source on the Aristo?

it's on the back of the manifold. i'm pretty sure it's the same for US 2jz's.

i'm pinching the red hose in the video, the other end of it is the ISC. there is a vacuum leak, but it's before the throttle body, shouldn't make any difference idling. but i plugged it up for testing purposes, no change.

 

[jdub]

Hook the ISCV hose to the stock location vs using a filter. Like I said, if you block off BOTH the ISCV and the PVC hose to the TB, the engine should die.


Edit: now that I'm done having my senior moment over here
My brain read "MAF" and not "MAP"...you are correct, the use of a filter should have no impact on idle at all.

A vac leak is the likely culprit.

 

[tlo86]

since you dont have a VSV on the p/s what are you doing about the vac line from before and after the TB? hopefully you capped the pre TB one off?

if you want to use the VSV the 1jz's have a separate piece that bolts to the p/s pump (and then the p/s line will bolt to it, the d/m line is not meant for 2jz's unless you have that piece already, usually you can opt for a basic autoparts store MKIV power steering line that is about 15$ cheaper than driftmotions and you dont need to pay any shipping and has a spot to bolt the VSV on the line) if you are missing the valve from the swap/or its broken the 7m one should work the same just pull it off the old p/s pump

 

[suprastanger507mgte]

I also suggest that you loosen the throttle cable fully and give it as much slack as possible, this will make the throttle close as much as it can, then adjust from there.
Once all vacum hoses are routed and or plugged properly, the idle should settle. I had the same problem at my first start.