My son's truck wouldn't turn over today even with a good battery. While diagnosing, I jumped the starter relay, with the key in the On position, and it spun over. Replaced the starter relay and now it spins over but still won't fire.

Could I have done additional damage while spinning it over by jumping the relay with the key in the On position? All fuses I've inspected, both under the hood & dash, appear to be fine.

Any suggestions? Thanks!

 

Does it have fuel pressure? Is the THEFT light flashing?

 

Fuel spark fire. Get a gauge check the fuel pressure. Then spark. You'll need a light testor to see if the coils are getting power.

 

Thanks guys but I'm here specifically asking about this particular vehicle because it seems somewhat random that the fuel delivery system would be compromised in this scenario. Unless, you've experienced a fuel pump relay failing during my sequence of events.

Truck wouldn't spin the starter...jumped the big posts on the solenoid (starter relay) with the key on...engine spun...replaced relay on firewall...truck now turns over but won't light.

What I'm expecting or hoping to learn is what could have been harmed when the relay died. To all of a sudden lose spark AND/OR fuel seems somewhat random to me.

 

It is possible that while changing the relay, the sudden surge of current could have popped a fuse or fusible link - honestly can't remember which of my Fords has them right now. I'd start with checking those. As far as damaging something by jumping the posts, I can't see how that could damage anything.

 

If the failure to fire occurred simultaneously with the relay replacement, check your wiring at the relay. Make sure you didn't put wires on the wrong relay terminals.

Otherwise, go back to post #2 and answer the question about the THEFT light. There's a reason we ask these questions, so do not ignore them.

 

My sincerest apologies...you are correct, i should pay more attention to your replies.

And yes, the THEFT light is in fact blinking! I didn't notice that until just now.

Thanks! Any guidance you can provide now is greatly appreciated!

 

Is the theft light blinking slowly before you try to start it, then rapidly after it fails to start? A slow blinking theft light is normal, but a fast blink means the PATS system is active and I don't know why swapping a starter relay would cause that unless you're using a spare key without the "chip".

 

He's using the key he's always used, with the chip.

Could the process of winching onto the rollback have set off the fuel pump deactivation switch?

 

Yes, did you check the inertia switch? Also what about the theft light question I asked?

 

Blinks rapidly through the entire process...as soon as the key is in the ignition, through the starting attempt and after the ignition is turned back off.

 

Found it, although I'm fairly embarrassed to say what it was. Appears while while checking the fuses under the hood initially, prior to us changing the starter relay, my son removed a 15A fuse and put it back in the wrong spot. Missed it by one but when I realized it, it started right up.

Thanks for all your help folks!

 

OK, so you now have a PATS issue. Go into cluster diagnostics mode and lets see what that says.

https://www.f150online.com/forums/li...explained.html

 

Ahhh, you replied while I was replying. Glad it's fixed.