Engine Idle Control
I could use some help here PLEASE... I have an '05 and hooked up the elevated idle as indicated on this thread and IT WORKS GREAT! (Used the purple/lt green as suggested instead of the orange to avoid locking up the torque converter - and connected it to Upfitter switch #4 as suggested)
My problem - I bought a Radio Shack 50K potentiometer (unfortunately all they had was a 20% tolerance 1/2W) and hooked it up between PTO_VREF and PTO_RPM as also indicated in this forum... but it didn't work.
Have tried various combinations, but can't get the variable aspect to work. Should it make any difference that it's not the 5% 1/4 Watt??? I have tested the Pot on a meter and it works OK.
Any and all help appreciated.
Thanks
https://www.ford-trucks.com/forums/s...d.php?t=325000
and this
https://www.ford-trucks.com/forums/s...d.php?t=303583
I did check those links out before I posted, (and did a search as well), but unless I'm missing something they don't address my problem. As I said I have done the original mod and it works great! I can flip upfitter switch 4 and it goes to 1200rpm every time.
I am trying to add the variable RPM control (also mentioned in this forum) using a potentiometer so I can adjust between 1200 and 2400 rpm. I did find a couple of references, the original posted by rocknmud. However when I tried to follow it, for some reason it doesn't work for me. That's where I need help. Could it be because I used the purple/lt green instead of the orange wire?? My setup works fine to activate the elevated idle without the resistor, so I don't see why it would be.
I am connecting the middle terminal of the potentiometer to the PTO_VREF (Orange with Red tracer) and the end terminal to the PTO_RPM (Orange with Yellow tracer).
I am not connecting to PTO_GND at all (and although document Q108 of the Truck Body Builders says to connect it in series...those posting on this forum have only specified 2 connections as above) I have also tried switching those connections - no luck.
I can follow detailed instructions, and I'm not afraid to get into the guts of things, but I'm not mechanically inclined and when things don't go like I'm expecting them to - I can't really troubleshoot, other than to go back and read the instructions again to see what I missed. In this case - I can't tell.
So I have re-read the Engine Idle Control section in the Tech Folder as you've suggested, but I still can't find anything to help me out here.
Thank you me1mckee and you Tim. I re-wired to the orange wire and then hooked up the potentiometer and it all worked fine first time. The fact that Radio Shack sells a 20% tolerance and 1/2 watt rather than the 5% 1/4 watt Ford calls for, doesn't seem to matter. (The advice given in this forum to use the purple/lt grn wire works great if you're NOT going any further than the set 1200 rpm; otherwise you HAVE to use the orange).
Drilled a hole in the dash and installed a rotary dial on the shaft of the resistor and it looks and works real slick..
Things were going so well, I did the Marinco heater block plug mod as well...It went real slick as well (other than I decided to put a hole in the bumper and burned out a new hole saw BEFORE I got the hole finished... oh well - all's well that ends well)
Now I gotta go back and read some more of these great ideas on the forum and pick out my next Mod!!
Ford Trucks for Ford Truck Enthusiasts
Last edited by 3BLADZ; Mar 31, 2005 at 11:13 PM.
I have a 2003 Ford 6.0 built May 2003, I read your threads hooking up the blue wire w yellow stripe to white wire w blue stripe with switch to get 1200 rpm when idleing, there is NO blue wire w yellow stripe. There is 6 wires in the bunch that are not connected to another wire they are ,brown,white,green,white/blue,blue,black/white. And none of them have power with key on. A white wire w blue stripe is one of the 7 wires in the plug at the peddel. I`m not sure if it is one of the same in the bunch I`ll try a continuity check. Any Ideas ???
Last edited by me1mckee; May 12, 2005 at 09:50 PM. Reason: sorry bad link, got it right now
If your not sure what you are looking at, look at the three wiring harnesses that come through the firewall to the left of the steering column shaft into the passenger compartment. The top harness is big, the middle harness is smaller than the top harness and the last harness closest to the floor is smaller still. The wire you are looking for comes out of the the middle harness where the harness routes up to the dash directly behind the parking brake handle.
One of these wires will be Light Blue with a Yellow stripe. This is the PTO function wire from the PCM. Placing battery power (battery positive) on this wire will command the PCM to raise the idle speed to 1200rpm as long as the transmission is in Park or Neutral and the service brake is released, meaning your foot is not on the brake pedal and the brake lights are not activated.
The other wire you are looking for is a White wire with a Light Blue stripe. This one is also easy to find. While looking under the dash direct your attention to the black OBD II datalink connector mounted to the lower part of the dash to the right of the steering column. This connector is what a service tech uses to hook up a scan tool which is needed to communicate with the vehicle PCM in order to check engine sensor data, engine trouble codes and to REFLASH your PCM. (You've heard about FLASHES haven't you???)
Anyway, look at this black connector and follow the wiring harness from the plug back up and inside the dash. Along the harness not too far up from the plug you will find the White wire with a Light Blue stripe included in the bundle of wires but the wire just stops short of the connector. Yes the wire does not plug into any one of the ports of the datalink connector.
This White wire with a Light Blue stipe is your positive battery source wire that you will connect to the Light Blue with a Yellow stripe PTO wire through a switch.
What I did was stop at Walmart's automotive section. I purchased some wire, a switch that has a Red illuminating paddle switch lever and some female crimp connectors and some butt connectors. (Note: The crimp connectors I purchased were manufactured or has 3M's name on the packaging and the plastic insulation on the connectors is heat shrinkable).
I used the wire and butt connectors to extend these vehicle wires so I could mount the switch under the dash to the right of the OBD II datalink connector. I crimped the female crimp connectors on the end of each wire so the wires could plug into the male terminals of the switch.
So far I have used two wires connected to the switch. The switch I purchased has three terminals. The last terminal is a ground connection that is used so that when the switch is turned on the switch paddle illuminates. (Note: The switch paddle lever on my switch is not bright enough to see during daylight and is dimmly lit and seen at night. Heck, with the idle speed at 1200rpm I don't think you will forget the switch is on).
Warning: This info is for a 2004 model year Power Stroke with the automatic transmission.
Thanks for the link to the Body Builder. After reading the information there I found that my speedo CAN be calibrated for a tire size that is not in the list of preconfigured tire sizes. Now all I have to do is convince some tech to follow the instructions...





