Techs please chime in, 6.0 HARD start

[6-ohPonyhaulR]

ok, for almost a year Ive had a hard start issue, It was getting worse so I started changing things.

I knew I had bad injectors..
I changed injectors, glow plugs, icp, ipr, cleaned turbo, egr deleted, RR fuel system installed, CFM large mouth SCT livewire and Innovative tuned. (all at the same time)

The truck runs great once it starts and will start right away after the inital fight. to fire the first time after more than about 8 hrs(reguardless of temp) it takes a little "help" (i call it help to save the lecture about ether....gotta do what you gotta do)

It has done this all summer, lows in the 70's and now into the 40s-50s.
I put an AE scan tool on it, all criteria good EXCEPT FICM V shows 40-42 v before start. After the initial start, it shows 46 constant and stays there.

I changed my FICM to a KNOWN good one yesterday and still get the same 42v before and during crank. give it some courage and it starts V jumps to 46-47 and stays.
every time i turn it off after the inital start, it is 46 and starts in 2 sec.wait 8-10 hrs(even in 90* days) and it wont start again.


is there a relay, or something I can check that feeds that voltage to the FICM?


Please please please help me ,
walmart is running out of ether!

[Socal-powerstroke]

There is a FICM relay, this relay is located by the fuse box in the engine bay, id replace it just to be on the safe side, 40-42v on FICM MPWR is low, the minimum spec is 45v... I recommed installing the scan tool when the concern is present and monitor icp pressure and ipr percent, if icp pressure is lower than 500psi when cranking you may have a high pressure oil leak, usually suspect the stand pipe o rings located in the high pressure oil rail under the valve covers or you may have a hpp stc fitting leaking, or if you own the early style 6.0L 03 or 04 they are not equiped with the stand pipes and the stc fitting, you may have the hpp going bad...

[6-ohPonyhaulR]

I saw that relay in my manuel. I wondered if that was what they were calling IDM.

Yeah i knew 40-42 was too low, M-chan has a great"what is required to start a 6.0" write up somewhere. My ipr and ICP both fall perfetly into range, oil pressure is good too, like 1100. Forgot to list STC fitting above but also replaced stand pipe rings and dummys when i did the injectors. when my STC broke before, the truck fired right off on a shot of fluid, yesterday I used enough to knock out an elephant.....


I'll try that relay. thanks

[m-chan68]

Originally Posted by 6-ohPonyhaulR

I saw that relay in my manuel. I wondered if that was what they were calling IDM.

IDM = Injector Driver Module

On a 7.3L this module is simply a "slave" to the PCM (Powertrain Control Module). Commands such as injection timing and cylinder identification still originate from the PCM. The Injector Driver Module only does what the PCM "tells" it to do.

Originally Posted by 6-ohPonyhaulR

Yeah i knew 40-42 was too low, M-chan has a great"what is required to start a 6.0" write up somewhere. My ipr and ICP both fall perfetly into range, oil pressure is good too, like 1100. Forgot to list STC fitting above but also replaced stand pipe rings and dummys when i did the injectors. when my STC broke before, the truck fired right off on a shot of fluid, yesterday I used enough to knock out an elephant.....


I'll try that relay. thanks

You just answered your own question. For what it's worth, if there were an issue with the FICM relay or circuit, you would be getting 0 volt readings for FICM_L, FICM_M, and FICM_V as well as a no-start. You better go get your FICM replaced without delay before it progresses into a vehicle "running on 4 of 8 eight cylinders", and then eventually a no-start situation.

[6-ohPonyhaulR]

ok, I replaced the FICM on sat with one from a starting truck.
the donor truck started right up no problems but in mine it shows the same 42v. although my truck idles quieter with the donor FICM

so, that being said. If the relay does what its told to do, that would put my problem in the PCM right?

so, anyone got a PCM for sale?