I have a 2002 F550, 7.3 PS. Increase problem with starting, even when temps are 50 and above. Truck will stumble with no power until op temp is reached, then seems to run fine. Engine light is on when you are in the throttle and off when not... or vise versa... but not steady. Went to have it checked out and no power to OBD port or cig lighter but fuse is good???
Glow plugs OK. Had problem with waste gate actuator, repaired, might be an issue??? Truck blows white/blue smoke when rev'd hard????
Any ideas?
R.G.

 

The cigarette lighter fuse also powers the OBD port.

Thread moved to the 7.3 forum

 

First off, welcome to FTE! Glad you're here.

Is it the engine light, or the fuel filter light? Sounds like the fuel filter light. Have you changed the filter lately? Also, when you have the filter out, on the right side of the filter housing near the top, there is the fuel outlet that goes to the regulator, and then to the heads. If you look inside that hole, carefully, you will see a screen, that sometimes plugs up. There are 2 10mm bolts on the outside of it that if you remove, you can pull the regulator off the housing and clean the screen. Be careful not to lose the o-ring, and be sure to line it up good when re-installing it. Now, what I do instead of removing the 10mm bolts, I open the drain valve on the filter housing, and with the filter removed, I spray it out with PB Blaster or WD-40, whichever I have available at the time, and I rinse the filter housing out. Be sure you're outside when doing this. You'll lose about a qt of fuel. I then fill the housing up with tranny fluid or diesel fuel, leave enough room for the filter, and install the filter.

 

If the fuse is good and there is power at both ends, then there is a break in the circuit downstream of that. You need to start chasing the reason why.
I'm betting that once you get that issue resolved the truck will run correctly.

 

On the 02's fuse #12 is what is shown for the OBD and lighter. Like Dan said, make sure the both sides of the fuse is hot and go from there.

 

i had a similar problem with no power to the obd and i was the f2.12 fuse mini 20a

 

Thanks for all the help. Much appreciated.
R.G.

 

Please let us know what you find to be the problem.

 

Oh yeah, welcome to the site and hang around here for a while.