Naw, the truck has sat since yesterday morning when I first posted. I let it sit till this morning, popped the hood, checked the reservoir level, and then posted my findings. The reservoir was within an inch of the top so that rules it out as bleeding off somewhere. Anyway, after I checked the oil level I put the plug back in and went back to work on my other appointments to think about the issue. Just now, after it's sat for since yesterday morning, I tried to start it. I cranked it for 15 seconds or so without it trying to start at all, just turning over with no romps or anything. I stopped myself and figured I'd better watch the numbers and see what was happening. Got my scanner hooked up and tried starting it. After a minute and a half of cranking it came to life. The first thirty seconds was nothing but cranking, and then it started to catch, as in started romp to life. if you let off when it first starts romping it will just die. keep cranking and eventually she'll come to life. The numbers are as they always are when this is going on, rpms are displaying on the dash and on the scanner, icp pressure is up around 2200, duty cycle is around 35% and voltage is around 1.0 and this is typical, since it's been here I've not had it start normal once after sitting. even if you let it sit for three or four hours it will start cranking hard after you take it out and get it up to operating temperature. After you get the vehicle started. it will start up perfect each and every time, till you let it sit. Sooo....here I am scratching my head again. The oil level is fine, the numbers are fine, the fuel is fine, the cps is fine, the air filter is fine. Glow plugs are fine, even if one or two were down it would still fire fine. This is very interesting.

 

is there any chance the IDM is causing these issues? I wonder if it's not supplying voltage to the injectors at times..i'm not sure, she's a head scratcher, that's for sure.

 

There is a possibility it could be the IDM. Did you clear the P1670 and did it come back? I don't think it's probably going to make any difference, but you might try cranking it with the ICP sensor harness disconnected. It also couldn't hurt to verify ICP with a mechanical gauge.

 

I have tried starting the truck with the ICP Sensor unhooked, to no avail. No oil in the harness or anything like that. it was one of the first things I tried. I didn't clear the codes on it but I will here shortly. Definitely a weird issue, it's also consistent, and by that I mean that you can let it sit and get cold and it always takes right about the same time to start, with the same symptoms. dry cranking for the first thirty seconds or so until either it gets fuel or oil. and then it begins to come to life. and it's always as if either the fuel isn't right there, or the oil isn't right there. but the fuel bowl fills right up, I took the filter out and watched it with the key on. Just a question, but is the oil pressure gauge on the dash watching the Low pressure oil side of the deal? This is a shame because one this thing fire's up, it's full of power. on a WOT throttle run the pump is putting out 2700 psi or so. Hmm...to be continued.

 

The dash gauge is nothing more than an idiot light on a stick. It has two positions, on and off. The sensor is just a switch on the top of the HPOP reservoir, and is on the LPO side of the system.

 

Also, I seriously doubt fuel is the issue. As long as there's fuel in the rail, the injectors will use it. This problem almost has to be electronic. Are you monitoring injector pulse width while cranking, too?

 

Okay, the only reason I say anything about that gauge is because sometimes it takes a good 30 to 40 seconds of cranking to come up. I had read that it was just a switch but it seems to come up at different times when cranking and just wanted to cover that base as well. I will monitor Injector Pulse Width in a few minutes when I try cranking it again. We're about to finish up here at work so i'll try watching it. my maximus scanner does a lazy job of listing off these PID's so sometimes it's a guessing game. What type of numbers am I looking for with this Injector Pulse width?

 

I've also noticed sometimes if you try cranking it when it is dry cranking, and you let off the key with it still in the on position and let it sit for a minute or so and walk away from it and come back that it will fire right up. Only sometimes though. Is our IDM anything like an FICM in a 6.0 and can be having issues when it's cold?

 

When the injectors are actually being commanded to fire, pulse width will be from 1.0 to 6.0 milliseconds. If you see a 0.5 ms or so reading, that's a standby value and won't fire the injectors.

 

I haven't heard of an IDM having issues when cold, but I'm sure it's possible. Temperature affects semiconductors, and could possibly cause it to malfunction. If you can run a buzz test when it's cold, that might help isolate the problem.

 

well I didn't get a chance to check the readings before I had to get home but will in the morning. So when you turn the key on, does the pcm do it's part and then signal the idm to trigger power to the injectors? how exactly does that process take place? Does the idm power the injectors individually? or by bank? the reason I ask is because when it's cranking over, one cylinder will start to light, and then as you crank all 8 will come to life almost immediately. the only way the idm was to make sense is if it was only powering one injector for a few seconds and then the other 7 were kicking in after a few seconds and was only having this issue after it was sitting for a few hours or till the idm cooled allowing the connections inside to be broken again. That's also assuming that our IDM works relatively the same as the 6.0's FICM. Hmm...well either way I'm going to get to the bottom of this tomorrow night after work. Whether it's a late one or not. I will post up what I find for readings on the Injector pulse width first thing in the morning though. Its hard to believe he went from it starting perfect, spending the day towing an empty trailer, coming home and parking it. to the next day its starting like this. Not to mention the master cylinder is going out on it, perfect brakes one second, then nothing, then some brakes, then no brakes, back to perfect brakes, both of these symptoms started appearing at the same time, after this trailer trip, but can't be related.

 

Doing a buzz test first thing in the morning will tell me if the idm is sending good current to the solenoids like you suggested pika, if I don't hear them that will point me in a direction.

 

Just a thought with the P1670 code try changing out the relay in the power distribution box under the hood then clear the code and see if it returns. I had that code a couple weeks ago and changed the relay for the IDM,PCM, and the other relay next to them and have not had the code come back (sorry don't have the location #'s). I also removed the wiring from the IDM and cleaned it then checked the resistance from the IDM to the UVCH just to make sure that I didn't have a wiring issue then checked the resistance from the IDM to the PCM via the EF signal wire. At the same time I cleaned all of the body grounds I could find there are a couple near the PCM on the firewall and behind the airbox which I believe is where the PCM grounds. There is a link for the IDM wiring somewhere but I don't remember where I found it just do a search for the P1670 code and you will find it.

 

Well, I walked out to the truck a few minutes ago to try some tests, turned the key on and let it sit, hooked up my scanner and started listing off the PID List I wanted to watch, by the way I can't do a buzz test on this particular truck because I haven't found the test yet, on my 02 and my new 01 350's the option is in a different place on this scanner, but when plugging it into this particular truck the scanner must use a different software for this year and month truck as I can't find the buzz test yet. anyway, as I listed off the PID list I wanted to watch, it took probably two or three minutes to set up. Turned the key to the start position and the truck fired right up. literally. just like it should have all along. WTH!!! So I'm down to looking over all the electrical components and wiring that can effect the truck's starting. Whatever is happening is within the first three minutes of a cold start. Tonight I'm going to trace all the wiring looking for corrosion, check all the ground and follow the IDM Wiring link as fiznuka suggested. The problem has to be electrical, and somewhere between the injection, the idm and the pcm. Danggg...she's running and starting like a top this morning. and there is no difference between this mornings weather and the past few days ive been fiddling with this thing. 80 degree days, nice and dry. the only difference is today I waited 3 minutes to turn the key to try and start it.

 

I just went out to try the truck again, it's sat probably an hour and a half since I had it running. I turned the key and it didn't wanna take off, dry cranked for a second and then had that romp but no start thing going on. all in all about 10 seconds of cranking. as soon as it started doing that I let off the key and left it in the run position. let it sit for a minute and a half exactly and tried it again. Vroom, fired right up. Whatever electrical issue it's having is taking place and fixing itself within a minute and half to three minute time interval after sitting for an hour or so.