makorunner

With the key in the run position and clutch depressed one wire (light blue?) on the driver side harness by the firewall smokes. I know I don't have a lot of information to give out but does anyone have any idea what could cause this? Any help would be greatly appreciated. Thank You, makorunner

kd3pc

You would need to identify that wire in a wiring diagram.

Is it the only wire that smokes and does it NOT smoke with the clutch not depressed??

I would look to see if the clutch linkage has worn a bad spot in the insulation and is shorting out what ever the blue wire is controlling.

Generally wire does not smoke, unless it is heating up abnormally, and that is due to either - too high current on the wire, or a direct short to ground.

Perhaps if you give a year and model on the truck, someone may have a wiring diagram or manual for it and could give you more specifics.

bests

makorunner

It's a 88'F150 302cid stick shift. I did just finish installing Shorty Headers, MSD Cap, Rotor and Wires. Cleaned the engine compartment (I covered all electrical components and Sensors as required) I hadn't started the Truck until a week or two after the Engine Bay was decreased. I also cleaned and painted the undercarriage weeks ago. The blue wire looks like it goes towards the nose......

makorunner

Of the Drivers Side grill/headlight area. It SMOKES with the key in the run/start position WITH the Clutch Pressed Down and it does start and seems to run fine for a few seconds until the smoke starts to appear than I shut the truck off (naturally). I will inspect the transmission, linkage and any wires under the truck first to loook for anything obvious
then l will try and trace the wire inside the wire loom. Thanks for your previous advice and I hope to hear from you again. Respectfully, makorunner

makorunner

O.K. Upon further inspection the "blue" wire is actually a gray wire with a yellow tracer. Spliced into the gray/yellow wire is the "blue wire" and then that short length of "blue smoking wire" is again spliced into a black wire spliced back into the gray/yellow wire. Right next to that wire is a red wire which is spliced into a white wire with a yellow tracer. Now both wires turn off from that main harness that runs toward the front of the truck and across the front of the truck to what looks like the solinoid area on the passenger fender wall. These two wires now in question is now the "smoking" gray/yellow wire and the white/yellow wire which go into a connector (Right next to each other) from the Driver Side Main Harness which splits to the right and this "offshoot harness with plug in connector" seems to go back toward the D/S firewall area. After repairing the gray yellow wire I re-inspected both wires for other obvious damage and found nothing. I am now going to start truck and see what happens? makorunner

makorunner

Here are some pictures of the problem area. I am not sure they will help but they might.

makorunner

Forget everything I just said. The only wire that is giving me trouble is the Gray with Yellow Tracer wire. It only "smoked" at the spliced section. I noticed the original wire is a much thicker gauge wire than the spliced Blua Wire. I cut out the "problem" section. I then started the truck. No smoke, and with the wire still cut everything seems fine. I have Headlights, Wipers and the Duel Fuel Tank Switch. All 3 work fine with the wire not connected to any thing. I have no A/C or power anything inside the truck. It was a stripped down model truck. Why do you think this never happened before I cleaned the engine bay and added the upgrades that I previously noted. I haved owned and driven the truck since November 2016. I am going to repair the wire with the correct gauge and see if it is still O.K. I will let you know how everything turns out after the wire repairs and test drive. If you have any thoughts please reply. P.S. The clutch depressed had nothing to do with the cause of burning wire. Just the ignition key in the "Run" position would start the wire smoking.

Thanks Again, makorunner
Problem part (Smoke) of wire from harness in Engine Bay.

makorunner

GOT IT! The "unused" 02 Sensor wire from the old exhaust manifold was pinched behind one of the stater bolts. No place for 02 sensor on the Headers. I cleared the pinched wire from behind the starter bolt and the repaired Gray/Yellow wire at the engine bay harness and all is well. If you hadn't told me to check the Transmission Linkage area I would have never found the problem. I also found a small crack (leaking) at the brake line near the R/F wheels brake hose where it goes through the frame towards the Master Cylinder. So I am repairing that now and hopefully I will be done for a while. I really appreciate your help. You are a "Gentleman and a Mechanical Scholar". Thanks Again, makorunner