Idle Issues - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

SiX_iN_a_RoW · 05-11-2003, 16:42

I am slowly ironing out the bugs since the mpfi conversion a while back

I have finally come to the idle issues

symptoms

very low idle on cold start-up, around 400rpm in park
once it warms up it will idle properly at one set of lights, then idle high at the next, can be up to 900rpm in DRIVE and 1200rpm in Park

on warm start-ups it will rev up to 1200rpm, then drop off to around 350rpm ( almost stall ) then kick back up to around 1000rpm then settle

I have tried cleaning the ISC, this helped a little but the problem still remains

Also, when trying to initiate the self test it wont rev like it used to, it will just idle very low at around 450rpm in park, when i disconnect the earthed wire it will sometimes stall or just stay at low revs until i switch it off, then turn it back on

The ISC is hooked up correctly and I have tried setting the base idle as per the book

SiX_iN_a_RoW · 05-11-2003, 20:24

I have removed the ISC and given it a clean out ( again ) and also checked for continuity across the terminals and it all checked out ok, I have yet to test the voltage at the ECU pin but will get around to it soon.

Also this morning I started her up with the ISC completey removed and obviously it idle really high but it didnt hesitate one bit, but i think if i were to have the isc installed and have my foot on the gas to replicate the revs it would hesitate

NZ · 05-11-2003, 20:57

Hi Anthony, you are earthing the wire before you start the car?
What I do is use a clip and use the negative terminal as the earth - cant get much better than that. Sometimes it took a fair bit to get a good earth. Youll have to wait at least 30 seconds between tests if something goes wrong ie turn the key off for 30 sec.

SiX_iN_a_RoW · 05-11-2003, 21:39

Karl, Yeah im doing how i always used to before the conversion \, I have made up a wire with a flat terminal on one end and an aligator clip on the other. Earth it out, switch the car on and it almost dies! idles very slowly at around 350-400rpm. The timing marks do seem to move but somethings a miss.

AcIlLaTeM · 05-11-2003, 21:49

Are you using original Motorcraft spark plug leads? I've been told that some aftermarket ones aren't shielded properly and can cause idle problems like in my car. I'm yet to get the original Ford ones back into it.

SiX_iN_a_RoW · 05-11-2003, 21:54

nah im using some high performance ones, but the prob just started happening after the mpfi conversion, nothing else was changed

oh by the way would the oil pressure sender not being hooked up create any dramas with the ECU? I wouldnt think so, but could it cause an error code?

sbcarden · 05-12-2003, 03:54

Are you 100% that the ISC is ok? I had one that checked out fine at the terminals, but when I applied voltage to it the valve inside move erratically/not at all/got jammed. This sounds exactly like your problem, high idle, low idle, etc. I got a new one from the wreakers off an LPG only ex taxi for $35. On the LPG only taxi pack option they were disconnected, but left on there so they have never been used......Just some food for thought

SiX_iN_a_RoW · 05-12-2003, 04:34

Well i am pretty convinced it is the ISC,
Today I set the base idle, when i disconnected the ISC it wouldnt start, turns out the idle was FAR too low. So i turned it up and followed the procedure. Hooked the ISC back up, and up she revs to around 1200rpm, if the isc is disconnected it will idle where it is supposed to. Another thing I noticed is, when it was "idling" at 1200rpm I put the air con on, headlights and turned the steering wheel and the revs dropped to around 500rpm, so obviously it is not doing its job.
Does anyone have one they are looking to get rid of cheaply? I think Im gonna disconnect the damn thing for a while! it doesnt seem to be doing anything other than causing a high idle so it cant hurt

sbcarden · 05-13-2003, 01:11

Like I said above, I think your best bet of getting one cheaply is from an LPG only ex taxi. Alot of EF's are coming into the wreakers now and the ISC's seem to get picked up pretty fast. Basically if your ISC is working and you've set the idle right, when you disconnect the ISC the car will stall. If you place a 0.75mm feeler gauge between the throttle stop and the base idle screw the car should idle at about 700rpm, once again with the ISC disconnected. Hope this helps....

SiX_iN_a_RoW · 05-15-2003, 22:49

Ok today I disconnected the ISC, set the base idle as per the book and she starts great and idles where its supposed to. It does seem to be running slightly rich on idle which is to be expected

Ok now another thing I have noticed...if I sit there in park, engine warm and rev it up to around 3000rpm, SOMETIMES when i let my foot off the pedal it will rev around 1100rpm, as soon as I turn it off, then turn it back on it idles as it should, which tells me it aint the throttle cable, does this sound like the TPS could be worn/faulty?