Michael_in_DE

1999 f150 5.4 supercab, 207k miles.

Story time:

Sits most of the time as a backup. My main ride failed so I started driving the truck. Drove it for several days in a row, filled it all the way up on Sunday. (something I rarely do as it sits most of the time). It sat overnight. The next day, I drove it to work. I went to leave and it wouldn't start. Sat overnight, next day, wouldn't start, wouldn't start...randomly started. Got it home, won't start.

What you actually need to know:

Battery was/is fine. Replaced relay, and checked appropriate fuses. all fine. COPS and spark-plugs were done 4 months ago. Been running like a champ for months.

After some research on here, it seems 90% of them time the answer is to replace the fuel pump. Should I check anything else before doing so? Any other advice? How to do it, where to buy parts etc?

Thanks guys,
-Mike

R&TBabich

It's probably the fuel pump, but I would check the fuel pressure at the test port of the fuel injector rail.
Harbor Freight has an adequate fuel pressure tester, #62623, for $20 (less with coupon).
Are you getting 12v at the fuel pump, or at least the output of the Inertia Switch?

Michael_in_DE

Thank you for responding R&TBabich, I have not done much diagnosing beyond the relays and fuses. I have a text out to a friend to see if he has a pressure test kit.

I'll have to investigate the power at the fuel pump and find out where the inertia switch even is to check those.

jstockert

Probably would be a good idea to check connection @ the crankshaft position sensor. If that sensor is loose it will not start.

the01kingranch

Switch is to the exterior of where the passengers feet would go up front. Behind the plastic