RaPtOr-T

I simply cannot get my car to stop idle hunting! I had just finished a vacuum hose job that I had to perform after breaking several vacuum lines getting to the waterpump/turbo coolant line that erupted.

When I did the hose job I removed the DT system and plugged the AWS. I used Dale's check valves and when everything was back together the car still shot to 2000rpms on initial start, but than It would slow down to about 1400rpms and just sit. Ocassionaly it would hunt, but not every time.

I ignored this because I wanted to see that everything was working properly and that I had boost, so I had been driving the car about a week when yet another coolant host ripped. This time it was the lower throttle body hose.

I now have the coolant line bypassing the TB, and did the proper modding to the TB. Everything back together and now the idle still flys right up to 2 grand, than it ALWAYS hunts between 1-1.5k, If it ever decides to stop hunting it idles right at 1.2k rpms, but a tap of the pedal sets it off hunting again.

I have adjusted the idle bleed screw, my TPS is in spec, I am 99% sure there are no disconnected hoses, DT is gone, AWS is gone, thermowax is gone. I have left the EGR and Switching Solenoids on....ISC has been cleaned/WD40ed.

The only thing I can think of is a gasket is no longer doing its job, I have removed the UIM twice, and the TB from the UIM 3 times. These gaskets seem pretty hardy, but are they shot? When testing the silicon hoses last week something popped lose and caused me to hit .9 "cm^2/KG" or whatever on the PFC, could this blow a LIM gasket?

Running out of ideas guys....help!

nashman69g

iTrader: (3)

Do u have a PFC? If so reinitialize it so that it can relearn the idle. I had the idle hunting problem and I tried everything. Then I reset the PFC and did the idle process--problem solved. Just remember to copy your settings over.

RaPtOr-T

Yeah I've tried to relearn, I'm still using the base map so its not a big deal. Heres what happens...

10 minutes of no load
Car is started at 64C, Idle hunts for about 1 minute than settles to 1300. Holds steady but occasionaly starts hunting, watching the PFC you can see injector duty being killed when it hits 6.0%. The fans came on toward the end but did not upset the 1300rpm idle.

10 Minutes of A/C load
Engaging the A/C bumped up the RPMs up about 100 or so, but it fell down to ~980rpms and was rock solid there the entire time, only 80rpms higher than it should be! Injector duty and timing was SOLID the entire 10 minutes.

10 Minutes of Electrical load
Disengaging the A/C rockets the idle up to almost 2000rpms, it drops than goes back to hunting ~900-1500 again. After a while it settled to 1300 but would hunt again every now and than.

nashman69g

iTrader: (3)

THe idle learn only happens after reset. You have to reset the PFC(IGN on, reset PFC, IGN off, IGN on, Start), then you let it idle for about 10 Min , then Elec load 10 Min , then A/C 10 Min. You'll know if its working when you start the Elect load--Give it a min and if the idle still isn't settled then the problem is else where... Check to see if the elect load sensor is coming on under "Sensor check". Try this and see if this works.

RaPtOr-T

Wierd, the sensor ELD is always "highlighted" with either no load or load, so does my car think its constantly under load? Stereo turned off any everything, I can't think of anything that could be drawing any current that would be considered load....

nashman69g

iTrader: (3)

Have u reset the PFC yet?...The ELC communicates with the ECU to tell the ECU its under elect load. This is the metal square box behind the ECU...Try this: Unplug your BAC/IAC/ISC or what ever u want to call it and see if the idle returns to normal.

RaPtOr-T

Yes! I don't know why I didnt think of this already since I actually turned the engine on when it was unplugged and it idled perfect. So whats the best way to go about the problem, leave it unplugged, or figure out why my ELD is constantly tripped? I guess for now I leave it unplugged and just set the E/L IDLE like it was my normal idle?

I'm going to reset and relearn it again with the ISC unplugged and the E/L Rev to normal and see what happens...

nashman69g

iTrader: (3)

U need to keep the ISC plugged in or it will be hard to start and idle with loads on it. You can try it I guess though--it can't hurt... Have u tested the ISC and checked the resistance value? Look at the wiring diagram of the ELC (section b-1b pg Z-30) and check the wires going to it for a load. The only signals that it could get are the lights, rear defoster, a/c, fans, or the inside fans on 3or higher.

RaPtOr-T

Well unplugging the ISC will just be a temporary fix. Even with the ISC unplugged the PFC decided to "learn" the idle from a nice 800rpms to 1100rpms, BUT it dosent hunt so I guess thats a plus. Whats wierd is the PFC is saying ELD even if the ELC is unplugged....The only thing I could find on having a constant ELD was not cutting the 4 wires on the PFC harness, which I did. I don't think theres anything wrong with the PFC wiring since the car was idling fine a year and a half before this with the PFC in. Could my ELC randomly have taken a dump on me?

I'll check the resistance and ELC wires tommorow afternoon. Thanks for the quick replies!

nashman69g

iTrader: (3)

Is the car hot when u were doing the idle learn?

Improved FD

raptor, what color is your car? I saw a nice black FD with sleek lights this afternoon and I'm wondering if it was you

PhDMDRX7

I had a similar problem. Turned out it was a leak in the PVC hose between the oil filler neck and the throttle body.

RaPtOr-T

This time it was, earliar it started @ ~60C Im not sure but its in my first post..

Nah, in fact I've never seen a black 7 around here? I'm Montego Blue and I've only been out this weekend to do some WOT runs to make sure everythings bulletproof. This month my car blew 2 coolant hoses and got backed into, its not looking pretty

I eliminated my PCV hose, but tommorow I'm going to recheck all the gadgets on the UIM for leaks...I'm fairly confident now its the PFC at fault.

nashman69g

iTrader: (3)

U need to find what E/L are on otherwise the idle process will never be done...Try to disconnect the battery for a min or two. Do u have any fan mods done? If u can get the E/L off then this should allow u to relearn idle...

Marshall

rxtech

Check your fast idle cam wax pellet.This is coolant fed assembly near the tps.Make sure it is not keeping the throttle plate open after warm up.Make sure your tps is set correctly and run your bypass air screw [this is at the bottom of the throttle body] all the way in to start with.Also make sure your secondary and primary throttle plate screws are not holding the plates open too far.Do this check by backing off the stop screw until it is not contacting the arm and than run it down until you feel the plate just start to open.Any excessive air bleeding into the engine at idle will freak out the pfc which is why the pcv valve hose leak caused this same problem.

rxtech

Sorry,i some how missed the start of the thread where you remove the thermowax.still check the plates real close,this was my problem with idle hunt.Good luck.

Archangel Studios

Just a thought. My idle was hunting after installing the PFC and I adjusted idle settings several times with no results. Turns out that somone (don't know when or why) had disconected the clutch sensor. While the stock ECU could compensate, the Apexi could not. Idle is rock solid now.

RaPtOr-T

Hmmm well starting the car in 1st with clutch in produces the following sensors to highlight...
FPD
APR
CCN
ELD
CLT

So the fuel pump is active....good
Airpump is active...good
Charge Control...I'm assuming this means either open/closed? turbos work so...good
Electrical load
Clutch is in

I have read that forgetting to cut the 4 wires can cause this, I have cut these wires. I have an after market alarm I tried unplugging that, it did not make a difference. PFC reads ELD with ELC unplugged or plugged in....I have disconnected the battery and held the brakes for 30 seconds. How can I determine what is causing the ELC to show load? I took voltage reads of each pin and did not find anything spectacular.

RaPtOr-T

Finally I fixed this, amazing how far the car has made it like this...

When I installed the PFC a year and some ago I must have somehow cut one of the wrong wires! There are 2 blue/yellow wires on the main harness piece, but they are not very close to each other (3 pins or so apart)...I must have followed the wrong wire and cut the wrong one! I patched this up and cut the proper wires, double checked everything and plugged the PFC in.

woohoo NO ELD!

What a stupid *** mistake, but wait, theres more stupidity to come...

The PFC was learning and still hunting, and idleing high! I went back to double check everything was set and guess what I found? Somehow I completly missed the HUGE idle adjustment screw/plate. Moved it out to the "barely touching" position and viola, perfect idle.

My FD was not done mocking me yet....

I closed the hood and started cleaning up all my tools, when walking around the car I found a HUGE scratch in the drivers side fender, this must have been from the leather jacket I was wearing when working this time

So now my car is running great but looks like total ****! Since my car was backed into last week I will try to have the fender resprayed when the rearend is if I cant buff it out.

Thanks for all the help guys.

nashman69g

iTrader: (3)

Good job...This should be a lesson to all--double check your work!

Marshall