i KNOW ITS NOT A MUSTANG BUT I JUST REBUILT THE MOTOR IN MY '86 BRONCO-302 EFI. IT WAS JUST A BASIC REBUILD. AND ALL THE ACCESSORIES REPLACED(ALT.STARTER.ECT.) NEW DIST., FUEL REG., OIL PRES. SEN., WATER TEMP SENS., TFI MOD.,...ANY WAY I CAN'T GET THE DANM THING TO IDLE RIGHT AT ALL. I REPLACED TH O2 SENS., YESTERDAY IT HELPED A LITTLE BUT IT STILL IDLES HIGH(1100-1300 RPM) I SET THE TIMING TO 10 W/ THE SPOUT CONNECTOR REMOVED. THATS ALL I CAN THINK OF, AND IT IS DRIVING ME CRAZY CAN ANYONE GIVE ME ANY IDEAS?
Is the idle steady or rolling up and down? Are you sure you dont have any vacuum leaks? Have you driven it? Any drivability probs? Have you tried loosening the throttle stop screw under the throttle body? Have you pulled the codes from the puter?
The idle surges about 300 RPM when the motor is warmed up, and has beed driven a few miles. It doesn't really do it when in gear. The truck seems to drive fine. When in gear it idles about 900RPM. I dont think I have any vacuum leaks that I can tell. (The brakes work, the cruise works, all the a/c controls work, ect.) When I turn the idle set screw down any farther than it is, it surges between 500-750RPM and sounds like it is going to stallout. I'm going to try and pull the code from the ECU.
Get some new gaskets, remove the throttle body and clean it out real good. Then set the throttle stop screw to where it is barely touching the tab that rests on it. Clean the IAB good while you have it apart. Take off the neg. battery cable while you are doing this, that will reset the puter. Hopefully it will learn a proper idle when you start driving it again.
This doesnt apply to you does it. I was thinking you had a mustang drive train swapped into it. This is a CFI system isnt it? Has a carb looking thing with 2 fuel injectors on top. I dont know too much about these. I imagine it still couldnt hurt to clean the throttle body. I dont know anything about how to set idle on these.
THE TRUCK HAS EFI ON IT, THE 302 EFI TRUCK ENGINES HAVE ALMOST THE SAME LOWER INTAKE AS THE 302HO. I CHANGED THE INJECTOR O-RINGS YESTERDAY BECAUSE I FOUND TWO OF THEM LEAKING, I ALSO CLEANED THE T-BODY WHILE I HAD IT OFF. AS FAR AS THE IAB(IDLE AIR BYPASS?) I'M NOT SURE WHERE IT IS. I ALSO ADJUSTED THE IDLE SKREW. IT RUNS MORE STEADY MOST OF THE TIME, BUT ON OCCASION IT WILL IDLE ERRATICLY WHILE IN PARK. WHILE I HAD THE INTAKE OFF I SAW SOME VACUUM LINES THAT LOOK QUESTIONABLE. I'M GOING TO REPLACE THOSE THIS WEEK AND SEE IF THAT HELPS. TO RESET THE PUTER I HAVE TO REMOVE THE NEG. TERMINAL FOR A FEW MINS. THAN RECONNECT IT AND START IT UP AND LET IT IDLE FOR LIKE TEN MINS. RIGHT? DO YOU THINK THE MAP SENS. COULD BE ACTING UP? I GUESS IF NONE OF THIS WORKS I'LL JUST PAY A SHOP TO FIX IT. I APPRECIATE YOUR HELP. THANKS