Hey all:

So my son was driving my 2010 F150 5.4 Flex Fuel to work and it died on him on the entrance ramp to the freeway. He said it just lost power and he had to pull over. When he called it was still running but would not go forward and had the wrench icon showing. I had him shut it off just to be safe. When I got there I checked the oil level then tried starting it. It would turn over, but not start. I checked the manual and it mentioned Limp Mode. I had it towed and it's sitting in my driveway.

Over then weekend I had done some work which needed to get done for a front wheel alignment. Upper control arms on both sides and a lower ball joint on the passenger side. While I was doing this I replaced the rotors and pads with new Wagner rotors and Bosch ceramic pads I had bought a few months back but never got around to installing. Everything went well. However....

When I did the lower ball joint I needed to pull the front shaft out, which was no big deal. When I re-assembled, I did not have the torque specs for the bearing bolt so I over tightened it. Never drove it though, but I noticed the wheel was tight when I spun it compared to the drivers side. I figured it was just the pads but to be safe I backed out the bearing bolt the next day and re-torqued it to specs. Still seemed tight though, but I figured it was just the brake pads and they'd loosen up after driving.

I am only mentioning this in case it's relevant. I did a quick visual inspection today and did not see anything wrong. I drove it last night and everything seemed fine with no burning brake pad smell or anything like that. And my son drove it to work Monday and Tuesday with no problems. Since I bought the truck I have not had any engine problems. Runs great.

So that's where I am at right now. I did some research and it all seems to point to the throttle body. Is that the case? If I just clean out the throttle body would that tell me if it needs to be replaced,or do I need to replace it straight off? It's a $100 part so unless it's for sure....

I work from home so I can go without for a few days and try a few things so any help I can get would be much appreciated.

Thanks in advance.

Ed

 

If I were guessing this one based on what I know about it so far, I'd go with the throttle body actuator got wacky. Since they don't usually do a great job of fixing themselves I'd replace it if that's determined to be the problem.

First though, I'd check for codes as well as check the fuel pressure.

 

I had a friend stop by with a scanner and found nothing. He started to swap out some relays and then looked at the fuel pump fuse and it looked like it was shorted out. Not blown really, but there were black marks on the tangs. We swapped it with another one and the truck fired up. I had ruled out the fuel pump because my son had told me the truck was still "on" after it died. What he ended up meaning is there was still ignition power and lights, but it had stalled. So based on this I was about ready to go with the throttle body, planning to disassemble and clean and replace if necessary.

So everything is working fine. But I wanted to share a quick story with you all. I had mentioned in my post having done some front end work so while my friend was checking relays and fuses I jacked up the passenger side and the wheel would barely rotate. I removed the brake caliper and it rotated fine so I think I have a bad brake caliper. That's not the kicker though. While I had the tire off I did an inspection and found the nut on the tie rod almost completely off. I had forgotten to tighten it down after doing the front end work. Well not the original job, but when I was done I realized I had forgotten to install the stabilizer bar linkage I had purchased. So I removed a few things to take the tension off to replace it. But never tightened the tie rod nut down. Had the fuel pump not failed, my son could have gotten into a serious situation if the tie rod had come completely off. I have had this happen to me before with one breaking on my old F150 and it's not a fun situation. Very scary losing your steering.

Anyway, someone was watching out over my son and me on this one for sure. Going to pick up a new caliper and everything should be good to go. Not sure why the fuse blew, so I'll be getting some spares to keep handy just in case.

Thanks everyone who replied.

Ed

 

Wow, that's a good thing from a bad thing!

I'd wonder why the fuse blew. If the fuel pump or anything else on that circuit was causing the circuit to sit right near the fuse's specification, then it will probably do it again.

 

Fuel pump Fuse? That would be fuse #27. Known issue with that fuse for 5.0 and 6.2 V-8's but I thought that was only an issue with those two engines. Maybe it's just way more common on those, but still potentially an issue for other engines?
It it was that fuse, I'd fix that asap. Do a google search for "F150 fuse 27 relocate". TSB: https://drive.google.com/open?id=0B6...nhOT0czZlF5M1k

 

Excerpted from the TSB ...There is no engine specification and/or limitation. And -ALL- engines can and have been affected as noted at this forum as well as F150forum.
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On the front end IE Brakes, make sure the pad ears are on the inside of the caliper.

Pads with the ears go on the inside.