TIL a loose ground wire can cost you 4 hours of diagnosing a no-start on a Ford 5.4

Last Saturday I had a 2010 F-150 come in that would crank but not fire. I threw a scanner on it and got nothing useful, no codes, no communication errors. After chasing fuel pressure and spark for way too long, I finally found the ground strap from the engine block to the frame was corroded almost clean through. It took me four and a half hours to find a simple electrical problem. Has anyone else had a ground wire drive them crazy like that?

2 comments

2 Comments

patriciamoore1mo ago

Dude, grounds are the worst lol. Had a Chevy Silverado that drove me nuts for a whole afternoon because the ground from the battery to the fender was loose, it would start fine cold but die after ten minutes. Finally found it by accident when I bumped the cable and the truck shut off lmao. Nothing makes you feel dumber than a simple ground issue after hours of checking everything else.

blair_green861mo ago

@patriciamoore read a thread last week where a guy had a similar issue on a Ford F-150, turned out the ground strap to the engine block was corroded to hell under the insulation. Ground problems are always the last thing you check even when you know better lol.