kevin phillips Posted March 17, 2009 Share Posted March 17, 2009 I've got a 1997 f-250 with a idle of about 1400 all the time and no dtc's.Checked the throttle pedal for binding,Checked for overfull of fuel in oil no concerns found on either.I switched out the ipr valve and it diddn't help.Unplugged the icp,no change in rpm.Removed pcm and checked for a chip in rear of pcm diddn't have a piggyback style chip but may be programmed.koeo icp voltage .21 volts koeo,ivs says idle on datalogger.app voltage shows .52 volts while running and ipr shows 10.54% while running and icp voltage running is 1.13 volts.Any ideas of anything else to check guys.Thanks for any help,been a rough week so far.I've got 2 6.4's with misses and knocks and the heads off one and now this.It's gotta get better from here. Quote Link to comment Share on other sites More sharing options...
hitechmech Posted March 18, 2009 Share Posted March 18, 2009 I've seen a bias tps sensor cause this. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted March 18, 2009 Share Posted March 18, 2009 Interesting Kevin. The only times I have seen a high idle on a Power Stroke the ICP was the culprit, and if memory serves me, biased ICP sensors were the problem. My experience with IPR valves typically causes a lack of power condition or stalling on decel. I've seen a bias tps sensor cause this. If you mean the accelerator pedal the pedal itself would have to be binding and not returning to full off position. Remember there is an idle validation switch and not just a TPS. Any discrepancy between the AP and the IVS and PCM ignores it and gives you idle and only idle. If you notice TP and IVS are off idle while the engine idle speed is up look for a binding pedal or floor mats/carpet interfering with the pedal. Quote Link to comment Share on other sites More sharing options...
kevin phillips Posted March 18, 2009 Author Share Posted March 18, 2009 The throttle pids are indicating closed throttle and the spring tension seems correct on the pedal.Unplugging the icp does not have a effect on the idle speed.Unplugging the ipr will stall the engine and it has been switched out.The vehicle has no mats in it to hang the pedal and the high idle is constant from startup just like it is set to idle that fast on a rpm controller but it dosen't have one.If the icp was acting up and causing the high idle wouldn't unplugging it change it if it was bias.I have unplugged the tps and ivs and started it and it still idles the same.Everyone i have ever seen will only idle with the tps or ivs unplugged but not this one.Unplugged the alternator to make sure it wasen't sending any ac voltage out.I'm wondering about maybe a pcm issue.Any more ideas? Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted March 18, 2009 Share Posted March 18, 2009 Thats all I can think of. PCM? Maybe... there is only one way to find out. Quote Link to comment Share on other sites More sharing options...
kevin phillips Posted March 18, 2009 Author Share Posted March 18, 2009 Found a used pcm in georgia,I will update when it gets here. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted March 18, 2009 Share Posted March 18, 2009 I remember one years ago like this, I think it was overfueling due to an injector problem of some sort. I'm sorry to say I can't remember the details. Future reference: Used PCM's (and other parts) are quite cheap and easy to order through www.car-part.com Good Luck! Quote Link to comment Share on other sites More sharing options...
robp823 Posted March 19, 2009 Share Posted March 19, 2009 im interested to hear what the culprit is on this one keep us updated.95-97 dont have the high idle feature for cold weather correct? Quote Link to comment Share on other sites More sharing options...
kevin phillips Posted March 23, 2009 Author Share Posted March 23, 2009 A used pcm fixed it.Opened up pcm cover and pcm showed traces of water intrusion.I have no idea what circuit was causing it inside.Thanks guys for the help and ideas. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted March 24, 2009 Share Posted March 24, 2009 Interesting. What led you to cracking the PCM open? Shot in the dark? Thinking outside the box, crap shoot? Just curious. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted March 24, 2009 Share Posted March 24, 2009 It's common to verify a bad PCM by looking or smelling the inside. They commonly smell burnt when they are bad. That, and a bit of natural curiosity, I'd bet. Good Job! Quote Link to comment Share on other sites More sharing options...
kevin phillips Posted March 29, 2009 Author Share Posted March 29, 2009 A old man that worked at the dealer when i started always made me take the gem modules, ect ... apart years ago looking for signs of damage and now I take alot of covers off of modules just out of habit i guess when things seem unusual or I suspect a module.I seldom see a pcm fail with ford but i have seen a few. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.