I purchased my FC from SR about a month ago. I recieved it, followed the instructions for install and found that the car hunted for idle. It would settle down, only to act up again when ever I touched the pedal. I called Ray at SR and he told me there must be a mechanical problem. I put the stock ECU back and had the compression and vacuum checked. Both were fine. I have since tried to install the FC again. This time taking extra care to unhook the negative battery cable, install the FC, run the car for 20 minutes, then continue to run the car for 20 minutes with the A/C on high. Car seemed to settle, but would hunt for idle every once in a while. I called Ray again and he told me to raise the 6 idle points by 50 RPMS. He also said I need to drive the car for a while. I have driven it for a week in all kinds of conditions, and the car continues to hunt for idle. Can any one help me? Where do I go from here? Should I ask for another FC? Should I go to a local Apexi authorized tuner? Should I go straight to jail, not pass go and not collect $200? HELP.

 

I have had my PFC dyno tuned and every once in a while it still does the idle dance. I think its just a PFC problem. One thing I did that got rid of most occurances is to go closed loop. If you don't know what that entails look at past posts (its in there). Personally I think its just a PFC problem in general. The software seems to constantly want to refine the idle point and gets confused occassionally. Good luck, and I doubt anything is wrong with the car.

 

For the #$$# time.

The PFC makes the engine idle more efficiently than the stock ecu. The results are that the revs increase so much that the "idle parameters" are now out of the control range of the PFC. This causes the "cycling" affect.

The engine is geeting too much air for idle now. You have the ability to adjust this parameter (air flow) by two methods! Try using the throttle body air bleed screw to bring the revs down or use the linkage idle set screw.

The idle set screw should be opened by about 1/4 to 3/8 turns from fully close throttle butterfly valve. The fast idle cam must be disengaged when making this adjustment. The air bleed screw should be opened enough to then control the idle so that when you get off the acclerator, the revs slowy drop to normal idle. Mine is opened 1/2 from closed.


These 2 adjustments are part of the simple basic tuning skills that every FD owner should know and learn before messing with anything else on their car! Just like changing plugs, oil, brake pads, etc.

It is so sad that so many owners try to mod their cars without knowing any basics.

 

Chuck,

I understand your frustration with us beginners. Your post helped me fix my problem. I am grateful. I am also now more educated. Thank you for your assistance and understanding as I become a better FD owner.

Scott

 

Easy killer, my car was tuned by RP (Chris doesn't know jack about 7's right?). They adjusted the screw and the idle settings in PFC. Mine still does it every once in a blue moon. Usually after sitting for a week or more. Granted this was not the situation of the above case. However, I'm just trying to help him out. I know about the bleed screw but I forgot to mention it. I'm sure there is something I could do to completely eliminate it but I don't know what that is. Were supposed to be helping each other not flaming each other.

 

I have nothing against beginners who really want to learn and try to learn. This includes getting and studying the manuals for your car, and learning the basics.

Too many do not even do this. They want someone else to tell them how to do everthing and solve all their problems. Even when a little common sense would do it for them. Many times they ask for help without even doing any basic diagnostics.

Too many mama boys with a man's toy!
I taught myself automotive skills and electronics while in highschool before most of you-all were born. My dad was a tough *** Marine career officer. I spent 7 years in the USAF during the Vietnam war perod. Being 56 very experienced rebel years young, I claim/take the right to bitch when I fell like it!

 

I have done all of the so called "Idle fix-it" adjustments and still have the idle hunt problem every once in a while. I can tell you that the more air-flow your car is getting the worse it is.

Another thing to check that helped my car out the most is the TPS which should be tested regardless of the idle problem. Look under the (ETC mode)/ (Sensor/SW Check) and check the VTA1 and VTA2 voltages. VTA1 refers to the full range mode of the TPS and VTA2 refers to the narrow range mode. Check your manual to see what the normal range should be and go from there.

I'm sure that most Rex's out there could use this quick check!

Good Luck!

Rob

 

SilverR2,

Good point about the TPS. I have tuned some cars
that even with the correct TPS voltages, they still idled a little off. Sometimes adjusting the
TPS a little high helps. This tricks the ECU to think the throttle is opened more than it really is. This was a problem with some of the earlier PFS PMCs. They would not go into "learn" mode at WOT with correct TPS voltages. The voltages had to be turned up higher.

I also find cars with incorrectly adjusted throttle cables.

Bad O2 sensors, bad/loose wiring, loose hoses, leaky gaskets, incorrect fuel pressure, bad injectors, etc. Many little things can affect the idle.

Always start with the easy and less complicated parts and work your way up.