High idle problem December 11, 2014, 11:17:44 PM When the car is started, whether warm or cold, it idles high and will never drop down to normal idle rpms. The car will lunge when put into gear and when put back into park the rpms jump back up above normal idle Quote Selected
High idle problem Reply #1 – December 11, 2014, 11:54:21 PM What year and engine?Many times this is as simple as a vacuum leak. Quote Selected
High idle problem Reply #2 – December 12, 2014, 03:24:33 AM 85 and its a 5.0. I thought that it was a vacuum leak but I checked all of the lines and none of them seem to be leaking Quote Selected
High idle problem Reply #3 – December 12, 2014, 04:45:01 PM Iac motor check it and or replace it. Quote Selected
High idle problem Reply #4 – December 12, 2014, 04:53:34 PM Quote from: TOM Renzo;441520Iac motor check it and or replace it.Hey Tom, i have been trying to reach you, have a friend that needs someone to look over a fox body Stang up in your neck of the woods. Can you PM a contact number? (Sorry for the thread hijack) Tom is hard to reach.... :-) Quote Selected
High idle problem Reply #5 – December 12, 2014, 07:45:27 PM 85 5.0 should be CFI, so you will not have a IAC.The CFI has "carburetor type" controls for fast and slow idle.Is the car stock? How long have you had the car? Did the problem just suddenly crop up? Quote Selected
High idle problem Reply #6 – December 12, 2014, 09:27:16 PM We are buying another place as we speak . Me and JR are swamped where does he live!! Quote Selected
High idle problem Reply #7 – December 12, 2014, 10:09:34 PM Quote from: TOM Renzo;441528We are buying another place as we speak . Me and JR are swamped where does he live!!hey Tom, my friend is in Scarsdale, but the car he needs looked at is in Greenwich CT. Quote Selected
High idle problem Reply #8 – December 12, 2014, 10:28:54 PM The car is completely stock, I've had it for about 2 years and it's been doing it for the past few months. Only has 90,000 miles Quote Selected
High idle problem Reply #9 – December 13, 2014, 12:23:57 AM Read through this thread. Skip over posts 6, 9 & 10http://www.foxtbirdcougarforums.com/showthread.php?36574-High-idle&highlight=fast+idle+can Quote Selected
High idle problem Reply #10 – December 13, 2014, 08:48:52 AM Try tapping the IAC with a small hammer or the handle of a large screw driver. If the idle drops, well... Quote Selected
High idle problem Reply #11 – December 13, 2014, 10:43:20 AM everything softtouch said + this>>>>>Normally on CFI applications the base plate gasket is cracked when you can not find any vac line broke or cracked or just flopping in the wind.Or, in one case due to my own fault, a mounting nut of the CFI was over tightened. motor was really cold and upon warm up things expanded then one of the 4 mounting ears of the cfi broke.I have a write up on how to take off the CFI, it isn't all that hard.start with the kit sold at stores called a CFI gasket kit or "EGR base plante kit"-you will get the cfi to spacer and spacer to intake gaskets.-I say start here because if you have not replaced this gasket kit, it needs done and will eliminate a lot of possible variables.now while you are doing this, and when you get the CFI separated off the car, look for the vac fitting on the rear drivers side.flip over your CFI and you will see carbon buildup,, chip all that stuff away.now would be an ideal time to split the CFI in half so you can remove the injectors and then extract and toss the injector screens.just start a tiny screw into the top of the CFI then yank real hard with pliers, the screen will come out with the screw.-this is the **ONLY** cure to the "hesitation off the line" from a stop that most people cant figure out. You know,, that half second delay where when you floor it but the car hesitates then it goes!As for the Idle speed control motor, a sure way to tell if it is functioning right is this.-start car-move the throttle lever by hand and watch the idle speed control motor and see If the rod electrically extends out a tad further.~it does this so that when you stomp the gas and then let off, the idle speed control motor will catch the throttle linkage and slowly back off lowering the rpms. this makes it so that the "let off the gas" part does not "instantly" happen, it acts as a buffer so your not putting stress on your drive train by going to high then low rpms instantly.-if the rod does not move out or in, its not working right or the wiring going to it is damaged (likely the case as most I see have bare wiring at the connectors for some reason) or its simply not getting its signal properly.-next you can simply unbolt the mount of the Idle control motor itself and lay it to the side, start the car and if the rpms drop, the idle speed control motor is either improperly adjusted or its not working right.-there is an idle stop screw on the mounting of the cfi itself if you observe what "causes" the linkage to "stop",, only adjust this (small flat head screw driver) if all else fails,,, this is a factory setting that should not be touched.next,find the red vac line on the diagonal vac tree behind the CFI.disconnect the line and cap off the fitting on the vac treestart car, if idle is low now and seems better, find the broke / bad vac line or problem areaNext,behind the coolant fill tank there are a bank of vac operated solenoids "fed by" the red vac line. the red is the source to all reference vac pressures for the black, tan, green and orange or white vac lines.there is a white plastic union at the bottom of the first or last two solenoids where vac pressure is parallel.at this white fitting there is a weak point in one of the 90deg bends and it will suck air thus increasing your idle. Next up is spray carb cleaner along all the vac lines / connections and near & far end terminations and listen to engine rpm. When the rpm changes (usually goes high rpm), then you found your problem area. Quote Selected
High idle problem Reply #12 – December 13, 2014, 11:55:35 AM jcassity, the 3.8 and 5.0 CFIs are not the same. The 5.0 doesn't have a idle speed control motor.Before going for "open heart surgery" I recommend making some simple checks.The thread I posted the link to will give a little tutorial on how it works.Warm the car up. Remove the air cleaner and plug any vacuum lines you have to remove to get it off. Start the car and look in the CFI to see if the throttle plates are closed. If the plates are closed and the idle is high, you have an vacuum leak. If the plates are not closed, check to see if the high idle cam or the throttle kicker plunger is holding it open.Let us know what you see. Quote Selected
High idle problem Reply #13 – December 13, 2014, 12:16:24 PM yeah, the 5.0 has the vac rendition idle speed plunger , on the driver front side and the choke on the pass side,,, i wasted his time on that part, the gaskets and vac line layout are the same though Quote Selected
Topic: High idle problem (Read 3164 times)
previous topic - next topic
