Truck Trend Garage: 2004 Ford F-150 King Ranch Starter Electrical Glitch
Question: I bought a 2004 F-150 King Ranch two years ago. I had some leftover cash from an Iraq deployment, so I bought some aftermarket goodies for it: Air Force One cold-air intake, JBA shorty headers, Borla cat-back exhaust, and electric fans. I also bought a $700 tuner with a custom tune. I liked the power I got from the tune, but it was doing a few things I didn't like (funky transmission shifting, etc). I reflashed the computer back to factory settings and have kept it that way ever since. The truck does everything I ask it to, but there have been several instances now, like on a recent trip from Carson City to Las Vegas (about 600 miles), where it won't restart. I turn the key and get nothing. No clicks, no noises, no lights of any kind. Give it some time, and it starts right up, no problem. On this trip to Vegas, it did it again but I just kept the key in the start position and it started after a few seconds. I now have a check engine light. I'm thinking of reflashing the computer again with the factory tune, but I'm not sure that's the problem. By awdding the intake and new exhaust, did I confuse the computer?
Answer: I'm not sure what you mean by "no lights of any kind." If you mean everything electrical in the truck is inoperative, or even just the instrument panel, there has to be a break in a circuit to a major power source. And intake or exhaust mods should not have an effect on starter operation. First, confirm what trouble code was set in the PCM's memory. If it's a simple no-crank condition, I'd look into the general operation of the starter circuits. Any kind of PCM programming issue would be a long shot in preventing starter operation. Aside from the heavy cable from the battery that powers the starter motor, there are several circuits and components that make the starter system work, including the ignition switch, the Digital Transmission Range sensor, the starter relay, the PCM, plus all the fuses and wiring in between. It's best when you have the condition present (no-crank) so you can quickly track down the loss of power or ground with a test light, and the correct electrical schematic. If you have both, practice your Direct Current knowledge. No experience? You might want to break down and get technician to do the job. There is a Ford technical service bulletin that may apply. TSB 06-19-14 deals with a no-crank condition due to a poor connection in the circuit between the starter relay and motor. This TSB supplies a part number for a kit to replace the electrical terminal at the starter motor, as opposed to replacing the entire wiring harness.
If you have a technical question regarding your pickup, SUV, or van, feel free to contact Alex, a master technician with the National Institute for Automotive Service Excellence. Send a letter to him in care of Truck Trend Garage, 831 S. Douglas Street, El Segundo, CA 90245, or e-mail us at firstname.lastname@example.org. Please include the VIN with your question. Due to the volume of questions received every month, we cannot guarantee that everyone's question will be personally answered or will appear in the magazine.
Can't wait for help with a problem you're having with your Truck or SUV? Ask the expert we trust here at Truck Trend Garage -- visit Alex Steele at www.RealWorldAutomotive.com.