Installed a PFC from SR Motorsports 6 months ago with a base map specific for my mods. Or so they said. Since day 1 idle surged up and down w/o load, w/load and w/ a/c. Got better over time but still not right. The only time it idles smooth is with the headlights on....idles like a dream. SR Motorsports says it takes time to learn my car. Has been 6 months and 1000 miles and it has not "learned" my car. They say there must be something wrong with my car and I'm out of luck unless I can get to their shop... IN CALIFONIA. I live in Florida. My car has only 29,000 strictly maintained miles on it. All rubber(i.e. vacuum hoses) is patent and in good shape. It is like brand new under the hood and idles fine with the stock ECU. Any Ideas?

PERFORMANCE MODS:
Dual K&N Filters
GREDDY BOV
MED M2 I-COOLER
GREDDY PULLYS
AIR PUMP REMOVED
HKS DOWNPIPE, No CAT MIDPIPE, RACING BEAT MUFFLER
FLUIDYNE ALUM RAD
APEXi PFC

 

Check your idle screws. Many times there are not enough air coming into the engine, specially with air pump removed. This caused the PFC to keep on adjusting the idle. The target without lights are 750rpm, and with lights are 800rpm.

 

Do a search - this has been discussed lots

In any case
a) as reza said, use the idle screws - they work magic
b) did you do the initial learning correctly ? if not you might need to reset - only do this though if you didn't do it correctly initialy - you still might need to do a after having reset/relearned

I had to play quite a bit with the screws (about a week) untill the PFC got the hang of it

This should solve your probs

 

Try adjusting your target idle rpm with the timing idle error correction off, set the timing
with the air screw and match the rpm on the idle in the commander. Set a little higher than
normal maybe 800-850rpm, to offset the loss of the air pump . Then turn back
on the idle error correction, It should work. I deal with a lot of big injector and turbo apps
and I never have seen any PFCs learn anything. Maybe thats because of major mods etc.
I dont know?

 

When installing a PFC a "learning" stage is sometimes needed. If you're sure all of your connections/adjustments are ok, then just sit there and let you car idle for about 10 minutes. It sounds like your idle is hunting. Double check everything and then let your car idle for a while. Some take up to 20 minutes to idle until the hunt stops.

Jeremy

 

The PFC programmers really missed the boat here. All they would have needed to do was program an idle setup function that would hold the ISC in it's middle of it's duty cycle range so we could adjust the idle bleeds to our desired idle rpm.

If you continue to have difficulty, try unplugging the ISC solenoid and then try setting your idle with the bleed screw (may find your tb linkage screws need adjustment as well). I went this route after a short while trying to set the idle with the PFC and surprisingly it works very well with a smooth idle that varies a bit depending on air temp only. I would have to reset the idle between summer and winter but we're only talking about a turn or so on the idle bleed screw.

After this I just removed the ISC and installed a blocking plate, great location to mount your aftermarket boost control solenoid as well.

 

^^doubt it...

all you need to do is the learning procedure. search for it under my name in this forum.

 

This might be a stupid question but did SR Motorsports pre-cut the "appropriate wires"? I got my PFC from Gotham Racing and they do not pre-cut the appropriate wires. I had to do it myself. But I hear that if you do not cut the appropriate wires the idle will fluctuate like that? Is this a possibility?

 

SR cuts internally.

TWOKRX7 is correct about the PFC, APEXI could have made it better.


Most idle learning problems on modded engines is caused by the ISC, or by the O2 control. The engine just gets too much air at idle compared to stock and thus reducing idle air flow is the best bet. My car was idleing great and then recently all I did was replaced the stock turbos with a GT35R kit. Then the PFC would not hold the idle correctly until I closed the throttle some.

Even when you turn the O2 off, sometimes the PFC still tries to do it. Bad internal programming. To stop this crap you need to turn O2 back on then off and best to use a DATALOGIT and change the O2 parameter from 1.047 to at lease 1.000.

I have been fighting these problems since 1999 with the PFC.
And do not forget the A/C problem APEXI also gave us!

 

Try to adjust the injector map around the idle area to around 2.2-2.5. This seems to help significantly. i also change the PIM map for 1.0-1.5V to help that idle hunting issue. Alot of times, when a ported engine is in the car, the pfc reads less vacuum so it goes to a different cell causing it to idle rich. You can also adjust the idle screw to smooth out the ramp down on idle (ISC not fast enough to compensate for the need of air).

 

Hey I noticed that you had problems with your fc, I just had one installed on my 7 and my idle is also giving me problems did you ever get to fix yours?