High Idle Please Help!!

[zerosum6]

To answer your first question Yes I did search this topic. No usefull advice so far.

1993 240sx w/stock motor and just an intake.Car idles fine until it warms up then it jumps the idle to 1600 up and down just a bit. What could it be?Electrical system is perfect new everthing,new injectors and fuel lines/filter,appear to be no vacuum leaks. New IACV. cleaned throttle body,MAF tests fine. There is no hesitation or sputtering everything else is fine.

Any helps or suggestions would be much appreciated, I just want it to idle even!

[driftedsilvia]

Check Ur TPS and CTS....

[vancouverbc]

zerothread?id=161700

[vancouverbc]

http://www.240sx.org/faq/index.html

Troubleshooting fast idle If your engine continues to idle real high after it's warmed up, check the air regulator unit. It's located on the passenger side of the engine, below the intake manifold, near the rear. There's a hose connecting to it. Pinch the hose when you are having the high idle condition. If the idle speed drops, there's a problem with the unit. Also check the electrical ground connections on the engine for looseness and oxidation.

Another thing to check for is an air intake leak somewhere along the intake plenum between the Air Flow Meter and the Throttle Valve. Check all the nuts for tightness that fasten the intake system to the engine.

RogoMan

[zerosum6]

New TPS and CTS already and new air idle valve [IACV], checked all seals to throttle body.

Could it be a swirl control valve?

[vancouverbc]

What is the idle rpm while it is warming up?

make sure you air regulator is not stuck open. only supposed to be open during warm up. make sure aiv hose to filter is disconnected,

disconnect o2 sensor and ecu temp sensor(not gauge sensor) to see what that does to idle. im going by what the subsequent poster said.
Modified by vancouverbc at 11:05 PM 4/18/2007

[rotorimp]

So the car is perfectly normal--until--the car warms up? Accelerates/idles fine? I would look at the sensors that the ecu does not look at until it goes into closed loop--like the o2 sensor and engine temp sensor. both can cause weird idles.

[zerosum6]

Which engine temp sensor,ther one in the coolant? New o2 sensor by the way.Currently cleaning out the PAIR[AIV] Valve for fun

[vancouverbc]

Which engine temp sensor,ther one in the coolant? New o2 sensor by the way.Currently cleaning out the PAIR[AIV] Valve for fun

Cleaning the AIV wont help. The AIV is pretty useless. YOu have to worry about the reed valves leaking exhaust/water into you filter box and maf area. Disconnecting the hose is an easy fix.

Both temp sensors are in coolant but only one sends signals to ecu.

[zerosum6]

I changed the one to the ecu and I cleaned it for the heck of it, I bent the valves so it always stays closed. I wanted to do this to keep a factory appearance.My next plan of attack is to change the pcv valve and check that system when I rebuild the intake manifold with new gaskets.After some testing I found the car does idle fine from a cold start to warm idle normally, I can even Grandma drive it and it will idle fine; but when I give it half throttle of beat it the RPMs dip up and down like a valve is opening and closing.Again I have a new CTS,TPS,Idle valve,o2 sensor,ecu, now non functioning AIV Valve,new used injectors,new fuel lines and filters,even have a new throttle body gasket.If you feel I missed anything just let me know...

[zerosum6]

OK,I think it's fixed----I bled the coolant system and my idle seems fine now.

[vancouverbc]

OK,I think it's fixed----I bled the coolant system and my idle seems fine now.

you had an air bubble around the temp sensor?

[zerosum6]

Thats what it seems like...

[zerosum6]

But it is back again,DAMN!!Idle just bobs up and down after I give it a moderate amount of gas, What could it be?List of things left according to service manual check compression,mass air,timing,pcv valve, egr valve, manifold gasket

[zerosum6]

ok did some more experimenting............it ONLY happens when 1/2 throttle or more is introduced. What could possibly be failing after load is introduced, as I have no problem accelerating?Again any help would be great!!

[enjoithe240sx]

i also have the same problem when i apply just a little acceleration (only while warmed up runs fine when i just start it ) it bobs down if i keep my foot where its at then when i apply a little more up 1500 it gets better. After so n so time warming up the idle rises slowly to 1500 cuz it cant take anything lower so whenim driving or im accelerating and the rpms are uder 150 it bogs down and is ****ty i cant figure it out if i apply enough gas and gets out of 1100-1500 its fine im pissed

[thomasjamal]

ok did some more experimenting............it ONLY happens when 1/2 throttle or more is introduced. What could possibly be failing after load is introduced, as I have no problem accelerating?Again any help would be great!!

Gotta bring this back to life... Did you ever find the problem? I'm having a similar issue.

[leper421]

Check ECU codes...

[thomasjamal]

Can't speak for the OP but I was getting a knock sensor code. I replaced that and the code cleared but I'm still having the problem with high idle.