Helping a co-worker diagnose his non starting (but healthy cranking) 2002 F-150 4.2L w/ 220K. It began by working intermittently (but never left him stranded), seemed the colder the weather, the more problems he had on initial start. He took it to a local-yokal mechanic who charged him to clear "security codes" and suggested he take it to a locksmith to have his keys reprogrammed as he says this is a common problem when keys lose their programming. That sounded a bit odd to me, so I offered to help. This was my ginuea pig for my first use of Forscan and I didn't see any issue whatsoever with keys or security system. Even went through key reprogramming.
This is what I observed:
Starter cranking just fine, nothing odd with the theft light, it comes on with turning the key to ignition and promptly goes out.
Using my scan tool to command the fuel pump ON, there is no output from the fuel pump but the relay DOES engage. I verified power to the relay output terminals. Go to the fuel line and press on the valve at the rail, and there is zero pressure in the fuel system.
Pretty sure this is enough to condemn the fuel pump at this point, but his "mechanic" insists that faulty keys will not allow the fuel pump to turn on. My logic is that if the fuel pump relay is engaging when the pump is commanded on through a scan tool, it should be working.
Any thoughts?
This is what I observed:
Starter cranking just fine, nothing odd with the theft light, it comes on with turning the key to ignition and promptly goes out.
Using my scan tool to command the fuel pump ON, there is no output from the fuel pump but the relay DOES engage. I verified power to the relay output terminals. Go to the fuel line and press on the valve at the rail, and there is zero pressure in the fuel system.
Pretty sure this is enough to condemn the fuel pump at this point, but his "mechanic" insists that faulty keys will not allow the fuel pump to turn on. My logic is that if the fuel pump relay is engaging when the pump is commanded on through a scan tool, it should be working.
Any thoughts?