Same song, different verse. And it still drives me nuts.....

A while back I posted that I had a 6.0 that sometimes wouldn't start, then it would, then it wouldn't, with no changes or improvements made. Turn great, just no start. Then it would, again....Much good discussion and assistance here, including the addition of a scan gauge to trouble shoot. Long story short, couldn't capture a fault code, so when it finally started again (it always does???) I drove it to a shop that knows diesels, and the 6.0 specifically, and left it with them, telling them to keep it and start it daily until it failed so they could diagnose the problem. Started everyday, for 7 weeks. They suspect an ICP, but until it failed again they couldn't be sure. Hated to replace something on a maybe. Finally brought it home last week in frustration, and you guessed it, it failed on my wife within a week and now won't start. I'm out of town but talked her thru the scan gauge enough to determine no fault or pending fault codes. Then I had her find the ICP indication on the xguage to see pressure during start. Was told by my mech that it should read 800-1000 psi to start, anything less would indicate a failure somewhere. Well, when she turned the start motor she got nothing on the ICP indicator, not even a zero. Before during starts it regularly showed 900 to 1100 during a start so I know the scan gauge is working, and the ICP WAS also. Now, if there was something causing the ICP to read zero, such as a stuck ICP regulator, the gauge should still show something, even if only a zero, right? I'm thinking (hoping) this 'blank' indication indicates a faulty ICP sensor or wiring harness. Am I out to lunch on this????

Also, I also realized that in my previous thread I mistakenly alluded to my '03 6.0, which was clearly a brain f*rt..... My apologies for the confusion. It is an late spring 04 model 6.0, with the ICP on the passenger valve cover, I hope...

 

Try pulling the ICP connector and try to start it again. It needs 500 psi to start and pulling the connector will give it the default number that should let it start.

 

I have heard the will start / will not start symptoms before.

It was a new engine install. A fork lift had been used to lift the engine at some point an one of the fork lift blades just nicked the reluctor wheel that senses the position of the crankshaft (I believe). I believe two teeth were slightly damaged so that depending on where the reluctor wheel stopped when the motor turned off, the engine would start or not start.

Now I may not be using the correct terms as I did not make the repairs and I have never seen a reluctor wheel; I just listen when others tell me problems they have had.

 

The SGII is having a brain fart. Sometimes they do at start up, especially if you wake them up before you try and start the truck. Tell her to try key for 30 seconds before she wakes the SGII up then crank the truck.

 

Will do, but will be a few days before I have access to it. I have to admit that once we got the truck out of the shop we drove it down to Phoenix where we expected to pick up a dining table we ordered next week. Now it's stuck there and I'm in Durango. Will be there this weekend and will give a try, if I can find a good illustration of exactly where the ICP is, and what I'm supposed to do with it. Cannon plug type????

 

Will try to talk my wife thru that this evening on the phone, although it may have to wait till I get down there this Saturday.......

Thanks all......

 

No motor work done, but you never know.......

 

A warn wheel or similar issue with such sensor system might give the same failure.

 

She just doesn't need to turn the SGII on before she turns the key on. The 03/04 PCM's are a little slow compared to the 05 and up trucks and the SGII responds slow also.

 

Understood....

 

In case it becomes necessary, or even I just decide to do it to take it off the table as a possible contributor to my starting problems, can somebody tell me if the ICP and harness are difficult to replace, even though they are located on the passenger valve cover. I saw lots of advice in the tech folder, but it all referred to the more difficult location on the older 6.0. Don't want to take anything for granted, and I may try replacing both on the 6th floor of an airport parking garage. In uniform, no less. Am I being overly optimistic, or just plain ignorant??? Also, parts numbers and potential OEM online suppliers would be a big help.....Thanx...

 

They are easy to get to and replace. All very accessible.

 

Thanks, my eyes are getting blurry reading ICP threads in the tech folder, but all reference the 7.3 or the early 6.0. Anybody give me a head start on tracking part numbers for the ICP, it's harness, and, what the heck, an IPR, all for the later mod 6.0????

 

I had a injector that broke in two pieces. It wobbled to one side a bit and the coil was shorting out on the oil rail. This caused a random no start one day. I showed up and unplugged the icp and it fired up. The truck ran fine with it unplugged. No miss no hesitation nothing. I changed the icp and had the same result. Cheesit told me to check the injectors and I found it. He said when somthing shorts out on that wire or whatever it causes your sensors to show shorted out or whatever. Ill try to find the thread and link it.

 

Wow, now that's some interesting info. The broken injector didn't cause a rough runner until you got it fixed? Hope I don't need to get into the injectors, that would definitely be beyond my pay grade, or at least my intelligence grade...But then again, being not too bright I'd probably climb right into it, then have to be bailed out with a tow truck Oh well, one step at a time.....