# 08 F250 high idle\potentiometer and cooling issue question?



## Luke_P (Sep 16, 2008)

ok here goes kind of two questions in one

1) I've got a 2008 f-250 with the 6.4 in it. Last winter even with the winter grill cover in it would not build heat to operating temperature when sitting from cold start or if at operating temperature and left idiling it would pretty quickly cool untill the gauge reads near the bottom. This would occur at temperatures around -10c for you yanks not much colder then 32 lets call it 20f and colder. The truck raises its idle a bit to try and warm up but it is not enough. question being has anyone else had this issue and what have you done about it?

2) while going over the above problem I researched the high idle function at the ford fleet body builers website(wealth of information) and I am going to hook up the high idle function and I would like the variable idle. For two reasons one for the above problem the other being it can't hurt to have it. From what I have gathered I require a potentiometer that varies between 500 and 50 000 ohms and can handle 12vdc which rules out most digital ones(from what i understand). 

Have any of you done this and what did you use? where did you get it? I would like something that isn't overly sensitive (ie 1\8 turn is half your rpm range) and robust enough to survive in a work truck at a reasonable price. I have some electricians at work looking into this but I bet plowsite could come through with something quicker!!

ps for anyone going to respond "just put 12 volts to such and such a wire or solder in a resistor it works fine" thanks but I have already found that info and would like the variable rpm so if it can be done for reasonable money.........


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## FEFMedia (Sep 17, 2009)

Well I can give you my feedback and take it how you want. 

1. The warming up issue. I plug in my truck every time its below 32 degree's. Mainly because it takes 2 minutes. I also Have the Ford external seat heater which doesnt do junx in my opinion.. course i havent tried it without. But long story short. Until I get moving it really doesnt warm up on really cold days.

2. High Idle. Well welcome to DPF baby. It sucks. When your truck is running it is collecting soot in the canister of your DPF system. After time your truck senses particles in the DPF and turns the Idle Higher to help burn those particles. Again all for emission bullcrap. Your idle going up is NOT trying to warm up your truck. Its to control the amount of particles in your DPF system.

Hope this helps. I am pretty sure the Canadian models and US models are the same in having the DPF system..


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## Luke_P (Sep 16, 2008)

FEFMedia thanks for the response, yes US and canadian trucks both have dpf filters and they are a pain. Yes I do have a block heater and I use it religiousily whenever the temperature drops below freezing I should have included that in my post. not to start a argument but

1. I agree my truck does not warm up to operating temperature below freezing wether the block heater has been used or not the owners manual says this will be the case, what bothers me more is that it will not maintain operating temperature once it has been driven around for a while and left idilng this bothers me because prolonged idilng of any vehicle isn't good, prolonged idiling of a engine not at operating temp is that much worse again especially diesels as they run cool in the first place and tend to build varnish and sludge and condensation in the oil easier in the first place(similar to propane powered engines). From asking around and reading the manual the only other option is the high idle function which is why I was wondering if anyone else has done the variable idle thing with a potentiometer. or come up for that matter come up with other solutions?

2. you are partially right about the raised idle it does have to do with emeissions and the dpf when the truck is not at operating temp it will raise the idle to try to acheive operating temp (from the owners manual, watching the gauge and seeing when high idle starts to turn on, ie as it drops to a certain temp it will raise idle and sometimes(if its not overly cold) successfuly raise it back to temp and conversations with ford diesel mechanics) as you will not meet emission standards on near any vehicle gas or diesel running cold which is why removing your thermostat or trying to pass a emissions test on a cold engine is a bad idea. the problem is the computer will not raise the idle enough to maintain this temperature why is beyond me because ford reccomends a high idle control if the vehicle will be left idilng in the cold for more then ten minutes (again as per the supplemental manual). JFYI the computer will not put your trucks DPF into regen either untill a number of conditions are met one of them being operating temperature. Not to try and lecture or whatever but I try to post correct info and have been corrected myself many times. Not even for me or you but someone reading this thread down the road.

*so anyways if anyone has any idea's that don't involve the high ide or have for that matter set up a variable rpm high idle please let me know what you think? what you used?* If i get it set up on my own I will post my personal experiences so its easier for others.


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## FEFMedia (Sep 17, 2009)

No worries.. some people dont read the little noticed they get when they buy the truck or buy a used truck and dont know how its supposed to run.. just trying to help out any way i can.. good luck in your search..


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## wnyps (Oct 11, 2007)

DPF, yank thank piece of S%!* off like i did and buy a delete pipe and programmer (spartan) u can idle for as long as you need with out worring about regeneration, plus more power (310rwhp more) better MPG(i see 14-15 city and 20+ hwy.) well,well worth the money in my opinion. Your truck will love you for it ! 2008 6.4 f350 SCpayup


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## Luke_P (Sep 16, 2008)

anyways so here's a update for anyone going to do the high idle deal. Before hand I am sure you'll want pictures and such but I am on dial up still so not going to happen, but I am suppossed to get something better in the near future. To be honest there isn't much i could show that you can't find at the ford body builders website.


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## Luke_P (Sep 16, 2008)

hit post by accident

So anyways heres what I used 

1 50k 5% tolerance linear pot that is good for 1\2 a watt and did its variance in one turn. A friend of mine picked it up in mississagua at a electronics supplier for 8 dollars. cost me a feed of wings. we found many sites that you could mail order from but most were american good for most of you, pita for me.

2. a 1\4 inch knob for pot also bought at electronics store and was included with wings (think they were a dollar or something)

3. some wire and non inslulated butt connectors\heatshrink

pretty simple to install. solder three wires to your pot one to the middle its the slider or variable ref.
one to the outside prong it can be your reference or ground depending later. third wire same thing.

you can check which is which with a multi meter but its easier to just hook it up and try it or you may not have a meter. once everything is wired if you want to turn the pot cw to raise idle and it is backwards switch the two wires around.

I installed my pot in the removable cover where fog lights would be, I don't have any so perfect spot.

run the three wires to the bundle of blunt cut wires by the e-brake where your upfitter blunt ends are. 

hook up the following wires small yellow\green to a twelve volt switch(ie upfitter) if you don't want a variable idle your done. when powered up in park or neutral with the e-brake on you'll get 1200rpm

the following get hooked up to your pot. small green this is your rpm input and goes to the middle post of your pot.

white\brown this is a 5v ref
gray\violet this is a ecm ground that completes the circuit

connect the above two to your two outside wires from the pot. start the truck and set the e-brake. hit you up-fitter switch with the pot in the middle of its range. your idle should ramp up. if you have to turn the pot opposite to what you would like switch the last two wires around.

voila variable idle much less bulky then the old stand alone units tie wrap your wiring, tape or heat shrink your connections and clean up!!


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## Dissociative (Feb 28, 2007)

some days i really love my emission free 6.0


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## KJ Cramer (Aug 20, 2009)

wnyps;815466 said:


> DPF, yank thank piece of S%!* off like i did and buy a delete pipe and programmer (spartan) u can idle for as long as you need with out worring about regeneration, plus more power (310rwhp more) better MPG(i see 14-15 city and 20+ hwy.) well,well worth the money in my opinion. Your truck will love you for it ! 2008 6.4 f350 SCpayup


What happens when you take it in for warranty work or emissions testing, is the warranty void and do you pass emissions? I have been thinking about doing this with mine for similar reasons, but I am worried about those couple of items.


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## wnyps (Oct 11, 2007)

No emissions testing here on diesels (Not yet) only safety inspections, but it only takes me an hour and a half to put it back to stock. In my opinion it is well, well, well worth the the modifications when im getting awesome fuel milage and power. My truck was in the shop at least once a month for repairs (3 EGR's, DPF replaced and towed twice for excessive exhaust gas temp, which limped my truck) in the first six months. Since the mods. dpf/doc delete and spartan programmer ive had 0% trips to the dealer in the last year and a half and 20k later. So YES it is it is well worth it. You wont be sorry at all.


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