Ok guys, I am about to take a shotgun to something soon.

Car: 1996 EK Canadian
Motor: 1999 JDM ITR
ECU: JDM ITR (P73) OBDIIa
Timing: 16 degrees

Problem: since day one, I have never been able to get it to idle below 1100-1200 rpms. Last couple of months I have been cursed with the hunting idle syndrom. When it doesn't or when it stabalizes it stays around 1400-1500 rpms. It will start hunting when I get off the highway and come to a light. And of course never consistently.

Now here is what I have done:

new intake manifold gasket
new TB gasket
new map O-ring
new IAT O-ring
new injector seals
new IACV
tried another distributor
verified timing (2 different guns)
verified timing belt
bled and re-bled and re-bled the coolant
checked for vacuum leaks
checked for exhaust leaks
no codes other than 20 .... ELD (canadian cars have no ELD)
verified TPS voltages (0.45 and 4.5 volts)
scanned all values with SNAP-ON Scanner ... all good
new O2 senser
no looseness in TB shaft either
compression good
leak-down good

now here is where it gets weird. Tried a P73 (Canadian) car idles @ 900rpm I couldn't get it to hunt. But rev it and let the RPMs fall it will stop falling @ 1500 rpm for 2 seconds then settle down to 900 rpm. Codes were VPS (vtec pressure switch) and secondary O2 (normal since JDM ITR has none of those)

Then I tried a stock P28 (Canadian). Idles like possesed demon ... 1000-2000 RPM consistently no matter what I do. I can even feel it under low RPM driving.

I have never, ever seen anything like this before.

The only thing I can think of is that the lack of ELD is keeping the RPMs high, but I can't explain the hunting since the first 6 months went fine.

 

Seems like the only thing you didnt do was jump the jumper and mess with the idle screw. That would be my last idea to do for you. Also do you have a FITV?

 

the first thing i would have done is mess with the throttle cable.

 

Well, there is no FITV on the car (OBDII), throttle cable has proper tension (aka none), idle screw has been messed with, with all combinations of gaskets, ecus, distributors, timing, etc....

 

you should try adjusting the tps sensor maybe its off, and the ecu thinks the throttle is open causing an eratic idle, I know these are rivited on and are not adjustable but you should check the voltage with a DMM, grind the rivets down and try turning it, and replace it with screws (there weird there like half rivets, half screws)

 

What engine harrness are you using? Just though I'd ask... But, you should really look into your TPS. I had the same problem and what I found out was that the plug on top of the throttle body was pluged into the TPS. I have a GSR in my EK hatch DX by the way..... anyways, the plugs, for the tps and the one sensor on top of the throttle body, have the same plug. I thought maybe it was switched or somethin. If not, that TPS of yours might be telling the ECU that its reading open throttle..

 

nope TPS voltages are perfect, and even with the SNAP-ON scanner it registers 8% at closed throttle and 90% @ WOT, which is in perfect spec. with the HELMS manual. The harness is a hybrid CX, ITR harness. And yes, the IACV wires were switched and the third wire discarded as per KATMAN's diagrams

 

I assume you followed the correct procedure for setting your idle. (Unplugged EACV, set idle with idle screw, plugged in EACV and reset the ECU).

If you have already done that, which I assume you have since you already replaced a bunch of gaskets. Have you checked the ECU signals for AC and other accessories? This is a total shot in the dark (because I can't think of anything esle), but if your ECU thinks that the AC is on then it automatically increases the idle. Maybe the ECU is seeing something that it's happening and raising your idle accordingly?

You are sure your throttle cable is adjusted correctly and your throttle plate is closing all the way? Did you check your EACV valve? If it is reading incorrectly it can raise your idle above where it should be.

Good luck!

 

Yeah, I checked and rechecked everything. Car has no AC or PS, scanner recognizes that there are no signals present. I don't see how two different IACVs can both be defective. And if the ECU is causing the IACV to freak, then what the hell is causing the ECU to tell the IACV to go nuts. Oh, forgot to mention new coolant sensor as well. And there is absolutely no shaft play in the TB, and no tension in the TB cable.

 

did you try a different throttle body???

 

the B16 we're tuning at the moment is having trouble because the throttle plate doesn't go all teh way shut when off the gas. . . maybe you're having the same trouble? Remove the throttle cable from the TB just to be 100%, and rev by hand. Also force the throttle plate shut (from the outside of course)
If this makes any difference, I guess you could try some CARB cleaner on the car.

Hope it helps. Let us know what happens.
B

 

oh and when you figure it all out, can you help me figure out how to wire my side mirror Defrosters on my EJ? I think I've looked everywhere!

 

well when I changed all the gaskets, I also cleaned the intake manifold and TB. I checked to see if closed completely and it was completely sealed. And there is absolutely no tension on the cable

 

maybe pcv valve also after you do all that pull out your 7.5 back upfuse for 10 secs to reset your ecu. are you throwing and codes?

 

I didn't change the PCV valve, but it did still rattle when I took off the intake manifold .... however it is next on my parts to change. As for codes, only code 20 (ELD) as stated above, and the ECU has been reset many, many,many times.

 

hmmmm
Can you post any pictures of your underhood? May not help but who knows maybe we'll find something wrong.
B

 

sure, I'll take some pics tomorrow .... it ain't pretty cause of all the winter dirt, slush and grime. :D