So, after a couple of days of really weird behavior, my old reliable friend has decided to stay up at the hunting cabin for the week without me. Unfortunately, this makes getting to work and picking up the kids from school kind of a PITA.

About a week ago, I jumped in and got the truck going, backed it up, and the electrical system went nuts. Dash lights going on and off, engine cutting out, bucking bronco headed backwards kind of thing. I got it shut off and stopped, and after waiting a few for the adrenaline rush to fade, it started right up again and went merrily on down the road.

Forward a couple more days of no-incident driving, and I'm cruising along at about 30 when it does it again, stops, starts, runs for about 20 seconds, does it again, rinse, repeat twice, then starts right up again and we're fine for another week.

No codes thrown, but I decided to put the tune back to stock anyway while I could just in case I needed to go blow the kids inheritance at the dealership sometime soon.

Drive it for several hours, park it for two days, start it up and run it for 5 minutes, park it again, and go to start it and it'll crank but the 303 relay is rattling like crazy and it won't fire.

At this point, it seems pretty obvious to me that with the 303 Relay acting funky, my Injectors aren't going to work like they should, so of course it isn't going to start. So I've got to figure out why the electrical leading to the ICM is going nuts.

I've got fuel pressure, and no fuel flow issues (bowl fills after drain nice and quick, and the in-bowl heater is disconnected like normal). Oil level is up and recently changed (~1200 miles). I've got good power with key off and while cranking. Replacing the relay and swapping them around in the fuse box just means it's a different relay clicking in the same spot.

I rode out on horseback, got to a buddies place and borrowed the phone to get a ride home, and started researching here. Found the Fuse 20 / 115 suggestion and went back this morning to check the rest of the fuse box with my multi-meter, but only found Fuse 22 blown. Replaced the fuse, but now she still won't start.

I talked to a friend who owns the shop I take our cars to and he thinks I need a new Engine Control Module. I think he's full of it , and that there is probably a simpler solution than that.

Any suggestions as to where I should look next, or do I toss this baby on the flatbed and kiss the kids college tuition goodbye?

 

Sounds like a battery or dirty terminals. When relays start acting up like that it usually is a low voltage issue. I would get your batteries tested and clean all your connections. What does fuse #22 go to?

 

Did the relay still chatter after replacing the fuse? Have you blown fuse 22 again?

Try swapping the 303 relay for the one next to it

Looks like relay 303 is for the IDM and fuse 22 is for fuel injectors / pcm. Someone needs to stare at the wiring diagrams and see what jumps out at them.

 

Fuse 22 is supplyed power by PCM relay and also supplies power to.
Break pressure switch
PCM at points 97 & 71
IAH relay
IPS
Glow plug relay
Glow plug control module

Your IDM is supplyed power by the PCM relay at point 67 to the coil of the IDM relay at point 86.
And BTW all this doesn't happen until the Key is turned ON.

Hope this helps.

 

The relay kept on chattering regardless of the fuse. The fuse didn't blow again after it was replaced. Sounds like it's time for me to go try and find a wiring schematic and get down to appreciating the $25 I spent on that multimeter again.

 

Actually, it helps a lot. That right there tells me I better sanity-check my GPR while I am under the hood this next round.

 

Here see if you can get into this site.
EBSCOhost - world?s foremost premium research database service once there input this.

user= marshall
passward= public

then Select= ARRC (Auto Repair Reference Center)
then select= your Year
Select= Make of vehicle (Ford)
Select= Type of vehicle F250/F350
Then Diesel
Wire Diagrams

 

That was an awesome reference link. It's going to be extremely helpful later today when I smack my mechanic around with that info. Reps given for that one.

 

Okay, the truck is back in my driveway and running like a champ thanks to some simple electrical work and the diagrams that Deluxe06 hooked me up with.

The problem was that 4 things were compounding each other:
1: Poor maintenance on my part (Dirty Battery Terminals).
2: Monkeying around without being sure what the heck I was looking at (Jumped the 303 Relay the wrong way, which screwed things up even worse).
3: There was more than 1 fuse shot in the fuse panel. (33, 22)
4: The 304 Relay (POA?) was working, but only intermittently.

The core problem: Bad ground connection for the ICM. Cleaning and putting terminal coating on both the negative terminals solved the problem immediately.

Bonus: Better ground seems to have helped the GPR cycle faster, and gets my fuel pump to cycle faster after key-on.

Again, thanks guys.

 

Fantastic!!! Glade you got it back running and all, was glade to help.
Any more problems just ask and someone will chime in.

 

Just put together a new motor and dropped it in the truck, and started havin this exact issue after about 60 miles of driving. IDM relay is buzzing/clicking at me and the WTS light won't go out. Actually, had the truck parked for a week or so and it had the problem when I got back to it. It will crank right over, but won't start.

So, would you mind dumbin down the fix you found for me? I'm great with a toolbox, suck with a multimeter.

Oh, and I don't have any blown fuzes that I know of. And no fuel bowl, or AIH. I removed the AIH relay as well.

I initially thought it was just a bad battery/no charge condition, the fuel pump I use is usually pretty loud with an even tone, and it was "warbling" at me a bit while the truck was doin this. But I was told that if it's cranking over battery connection or strength shouldn't be the issue.

 

Just because it is cranking over doesn't rule out battery strength, especially with the diesels. There's a lot of things using a lot of juice under that hood.

 

You were misinformed. The engine will crank over with less then 10 volts. Make sure your battery connections are clean and tight and the batts are at full charge.

 

Awesome. Back in line with what I was thinking, now to find what drained the batteries in one week.

 

They don't put two batteries in these things just to fill up space.