Just as a baseline...

I have a PFC/commander ver 5 in a 94 touring
dp
catback...THAT's IT!!!

When I installed the PFC the idle would SMOOTHLY hunt then in a matter of minutes it would idle at around 800rpm. GREAT I thought.

Then after some drives and warming up the car the car would just die if I came to a stop. The car would never hunt before it would stall...it would just stall

As in other post that I searched for, I ended up adjusting the idle air bleed screw underneath the throttle body.

The interesting thing about everyones post was that no one clearly mentioned which way to turn the adjustment.

I tried to turn the adjustment all the way counter clockwise. All of a sudden the idle starts to bounce from 1000-1500. Good I thought, I read that it will do this then settle down....NOPE!!! Just continued with the bouncing idle then it would stall!!!

So then I turned it in almost all the way clockwise....almost right away the idle temporarily goes up to 2k...than nicely (without bouncing) goes down to 800....ROCK STEADY. I then let it idle for 10 mins....defroster for 10, ac for 10...NO probs...rock steady. I have driving it since and it did stale once but I am hoping it is still learning and will give it a week...otherwise I will turn the air adjust a couple more turns clockwise....


***my only question is to the guru's out there...turning it clockwise....am I addin or removing air from the idle??!??!?! Hope this helps somebody!

 

this is the air bleed screw...I think courtesy of Jonski....

It helped tons in finding this damn thing!

 

Clockwise closes the opening and thus admits less air.

 

ahhh...that makes sense from what I was reading about the PFC needing less air for idle...

Thanks!

 

All this time I've been d!ickin with the wrong screw! I was like "how the hell do you get a screwdriver in here without taking off the oil filter?" ...doh!

 

hey I feel good, actually contributed something!!!

The first time I had to remove the elbow to see where the scew was....now that I know where it is, I can just stick the screwdriver in and adjust the idle without removing anything

 

I received this e-mail from a friend of mine in WI.

Ken a good tip I have had for a long time had a hunting idle I unplugged the idle motor control and the problem is gone .the power fc and the motor control didn't understand each other the idle has never been this
good stays wherever you set the manual adjustment.

 

Which one is the "idle motor control"? Is it the same as the idle speed control (ISC) solenoid?

 

Yes, its on the manifold near the firewall it’s a motor and is horizntal to the ground.

 

can someone take a picture of it for the mechanically challenged?!?!?!

 

I dont get what you guys are talking about... I plugged my PFC in set up my maps and set my idle to 900rpm and it sits exactly there from the second I start it...

 

Twin triangles,

what version do you have?? What mods and maps did you "plug in"

 

Hmmm...I'm doing some idle-hunting troubleshooting too. I'll let you all know whats going with my FD when I get mine figured out. :p

Right now, its doing the damn hunting between 900-1500 RPMs in about 1 sec cycles when the car is warm. The problem is less severe when running A/C, and is even less severe when A/C and electrics are running too. I unplugged the air pump, and hunts less, and recovers from its hunting trips sooner. A mechanic diagnosed me with a bad Air Control Valve. I'm gonna swap it out later and see if this helps. I'm also gonna play with that air bleed screw. Wish me luck!

 

Well, I'm no guru...But I do know how to fix this problem. Rynberg helped me out with this one.

You need to do the PFC idle learning routine:

From the commander, reset the PFC
Key on, Key off.
Now let the car idle for 15 whole minutes
Next turn on the rear defogger while the car idles for another 15 minutes, then turn on the parking lights and let the car idle for another 15 minutes.

That should allow the PFC to "learn" how to control the idle with different electric loads.

 

jpandes,


I did that before and the PFC didn't learn the idle....that's why I had to adjust the air bleed screw

 

Listen to what ken said about the ISC. I had tried everything untill I unplugged the Idle speed control on the back of the upeer intake manifold. It has a white plug. Just unplug the stupid thing when the idle is screwing around and see if it helps. My car would start bouncing all over the place and would not keep running when it was cold, I unplugged the ISC and everything is perfect.

 

I thought I would share my experience.

I just installed the PFC and was searching for the fix for the bouncing idle. and my fix was the idle control motor (white plug on UIM near FW.

Thanks,
Sean

 

I've reset my PFC 4 times and done the idle learn thing. So far I've wasted about 3 nights letting it learn itself. I've even adjusted the air bleed screw too. I am going to unplug the ISC tomorrow. I hope that works... I am getting tired of the freakin' idle bouncing!

 

The first thing that should be checked when having idle issues, stalling or surging, is the clutch switch. You can check it with the commander under etc. This is a very very common problem. The switch can be taken apart and fixed with a standard ballpoint pen spring. It is important to know that you can, by adjusting the air bleed screw, fix the surging and stalling problem for the most part, but on occasion the car will still stall and or surge.

 

I appreciate the tip IGY.
Checked the clutxh switch, it was working.
I unplugged the ISC and the car would stall. I finally got it to idle half way with out stalling and then plugged the ISC back in. It has been better ever since.
I don't know what that did but it worked for my car.

 

I was having the same idle gremlins you guys are describing. Here is what I had to do to fix mine. I had a bad clutch switch so naturally I started there and replaced the switch. I have a SRmotorsports 9.5 flwheel and I called a friend who has the same FW. Apparently if you have a LWFW it helps to bump up the deceleration fuel cut recovery RPM settings, because with a LWFW the engines RPMs drop much faster than what the PFC expects. I bumped them up a little and ouila no more idle hunting.

 

Hey guys,

I'm having idle problems with my car also. When water temps hit 88 degrees on the PFC, the idle bounces from around 1200 to 2200 cyclically. Upon a warm start, the car revs to 3400 RPM, holds...when I blip the throttle it starts bouncing from 1200-2500. This is without any electrical load. But EVERYTIME PFC reads above 88 degrees, it happens.

Does this gremlin sounds familiar? Should I unplug the ISC?

Thanks in advance,

 

mine is doing the exact same thing as FD_Newb_1974s. any help would be greatly appreciated.

--john

 

Update. Idle hunting again. I'll try some of the other "fixes" today.

 

I gave up on the ISC years ago and have never looked back. Ever since I installed the PFC the idle was garbage, recently took it one step further and installed a blocking plate. All you might need to do is adjust the idle screw under the elbow if the ambient temps change such as winter to summer etc.

If your idle speed control works then buy a lottery ticket, you're a lucky one.