1995 Ford F350 7.3 diesel 4x4 crew cab, over 400xxx potentially over 500xxx? Km

So Saturday night I left my lights on all night. Killed my batteries. Sunday evening I decided to give it a little boost and start it. No luck. I was trying to boost from a small Kia car. Not optimal and I had to let the batteries charge up a bit before I could get a good crank. Anyhow I didn't get it to start blaming weak batteries and decided to get my battery charger from my shop on Monday and charge them up good and give it a go with good batteries.

Here goes the list of a few things I've tried.

-Batteries are solidly charged and I can crank on this ****er for a solid minute without it slowing down. Both are about a year old and 850 CCA
-Starter is about as old as the batteries, upgraded to the super duty model and also works great.
-Fuel bowl recently rebuilt by myself within a few months and filter is pretty fresh. Not entirely ruling out a clog somewhere but I have my doubts. Fuel looks very clean in the fuel bowl and it was full
-I have not confirmed fuel pressure at the fuel bowl, I'm currently lacking the tools to do so. Fuel pump is about a year and a half old and I've had no reason to doubt fuel pressure up until now.
-Ive checked all fuses with a multimeter in the dash and under the hood. I had one larger 30 amp fuse. I want to say #18,21 or 22. It was for charging a trailer battery. It was blown. I was towing a trailer on Saturday perhaps it blew then? Could this be in any way related? I jumped across it since I had no fuse to replace it but it appears to have made no difference. Perhaps it may have blown when jumping or recharging the truck batteries.
-I swapped around my relays with the Horn relay and tested out my horn and vice versa with cranking. All relays seemed to check out as fine. Confirmed via horn honking and no starting.
- Oil is topped up and I've peaked into the HPOP resovoir and there is oil up to the top. I have not checked HPOP pressure as once again I lack the tools.
​​​​​​-I once pulled a code for the CPS but my tach still moved, so I changed it with my spare. (And broke the Oring godamnit). Once sealed I no longer pulled a code and still no start. No code either but I didn't feel my tach was moving as high as it had been with my original so I swapped it back. No code coming up for CPS since. Tach hovers around 2 to 3 hundred under a good crank.
-Wait to start light does come on.
-I have had the truck plugged it. It's about 35 degrees celcius out and the block is damn warm.
-I got a tiny puff of smoke on one crank, no new codes showed up and definitely no firing.
-I tried starting with the ICP harness unplugged. Did I do this wrong? I assumed I should just unplug the harness when going off the Crank/No Start flow chart. Should I have removed the whole sensor. Code came up as ICP failure and no start/no change.

I have been regularly pulling a P1668 CODE, IDM to PCM communication error. I have seen the list for possible causes:

Open fuse
IDM relay
Open or shorted IDM enable circuit
Open/short in EF circuit
Open/short in FDCS circuit
IDM powering circuits
PCM

My question aside from any other advice someone may have is how do I go about testing these things. I seem to hit a wall finding any information regarding this. I'm a bit at a loss and way too broke to try and throw parts at this truck right now. Hoping to find the one and only solution to this problem.

Thanks FTE!

 

If there is no smoke your injectors are most likely not firing. Other than changing out your IDM with a known good one, you can start by checking the wires between the UVCH and your IDM connector for any open wires.

You didn't say which fuse was burned. Both the IDM fuse (8) and the PCM fuse (9) are 30 amp. The PCM fuse also powers the fuel bowl heater element if I remember correctly. Jumping a fuse can cause some serious damage, so be careful when doing that.

Pulling the connector off your ICP sensor just sets the IPR to a default 700 psi.

I hope someone who has gone through this will be able to help out. Low voltage does weird things to these trucks. Double check your grounds and keep your batteries topped off on a tender until you can get this figured out. You need at least 300 rpm to start these engines.

 

https://drive.google.com/file/d/0Byb...1qRU1VVGc/view

There ya go

 

Have you tried a buzz test?

To your ICP question, NO, you do NOT want to remove the sensor. You'd get a nice blast of high-pressure oil out of the hole when you crank the key if you did that. The purpose of that exercise is to eliminate a faulty ICP electronically from the PCM inputs.

You really shouldn't just jumper fuse sockets, esp. for something electronic like the IDM. Spare fuses of all applicable sizes and fuse ratings are as important to carry in the glove box as spare bulbs of all applicable sizes/types. Granted, those maxifuses aren't cheap, but they're cheaper than the components they protect.

 

Yup I have followed the flow chart. Haven't yet been able to check fuel bowl pressure or HPOP pressure. The P1668 code has made me skip the steps a bit and dig into that. I'm definitely hung up on trouble shooting it though. At work right now but hopefully I can dig into it again tonight just looking for ideas to pursue.

The 30 amp fuse I mentioned was one under the hood that was labeled in the owners manual as being for charging a trailer battery. I just couldn't remember which location it was numbered as. Seems to be unrelated to my no start issue. All other fuses and IDM and PCM relays check out fine.

 

Good note on the ICP haha.

Haven't tried a buzz test. I've just been pulling my codes off of an edge evolution programmer that came with the truck. Don't have a proper scanner for a buzz test.

 

PCM relay has been known to fail, can try to swap it with another relay

 

Yes sir, I swapped around the relay for the horn with the IDM relay and the PCM relay. Both were able to give me a horn honk. Going to do some thorough multi metering tonight and verify I have fuel pressure and then perhaps bite the bullet and buy a scanner to do a buzz test. I shall report back later.