2003 6.0 KR
Back story, this truck ran flawlessly two years ago in which it was parked, since then I’ve done a mild resto on the vehicle, bodywork and paint. The truck was only started intermittently and briefing to move as needed and ran without issue. Never put under any load. I finally put it on the road the other day and was driving it around for maybe 2 hours. I was a little low on fuel so I went to fill up, as I pulled into gas station the truck started to kinda surge and not sound quite right. I topped up the truck and it fired right back up but it wasn’t running at all. So I decided to turn back home, before I made it a few kilometres the truck went full misfire, shake rattle roll type of thing so I pulled over where I could and shut it off instantly. Since then the truck hasn’t start. Initially there was a code for cyl 5 contribution but since it’s been cleared it hasn’t shown back up. Otherwise no other codes than the ones from egr delete.

Since then, I’ve replaced the Ficm with a known running one, shows 48-48.5v cranking and 10-12v on the logic side depending how much cranking I’ve done that day. I replaced the Ficm relay and it shows 12v. Replaced fuel filters and I’m getting substantial fuel to the secondary bowl. There is little to no injector buzz, seems to change from crank to crank, but nothing like a 6.0 should. All grounds and harnesses have been gone over. Plugs are in back of Ficm tight! Ficm sync happens upon cranking. I’m getting upwards of 140RPM while cranking

I’m showing oil pressure in the dash as well as an ICP of over 1500psi while cranking. IPR is 14% key on and goes to mid 50’s while cranking. I tried unplugging ICP just to check, no change.

I’m learning towards stuck injectors but all help is wanted and needed… I have yet to try some silicone spray as I’m hesitant, I will unplug the GP’s first. If it did run in spray what would that tell me?

 

I would troubleshoot the lower than usual cranking rpms

 

I thought I read that you only need 100 rpm cranking to fire. So I assumed my values were already sufficient?… How would I go about troubleshooting if that really is an issue? What would cause that

 

Also if the truck was running when all this occurred, what would that have to do with cranking rpm?

 

Many people have identified that 150 is really the minimum for a reliable start. Typically you should have 170+ cranking rpms.

The PC/ED manual does indeed state that 100 rpm is minimum required, but my interpretation is that the 100 rpm is for the sync requirements or issuing a fueling command, not actually engine starting.

Also, with 150 rpms, you will get better oil pressure than with 100 rpms.

 

I’m reading that lower cranking rpm’s can be caused by the CPS.. but isn’t my ficm sync telling me the CPS should be good?

 

I think you have two issues.
Slow cranking and a bad injector or two.

What scan tool are you using?

 

I was using just my sct x4 at first and then I went and borrowed a big snap on brand one that I could read rpm’s. the cranking doesn’t sound any slower than normal.. all the things I tried to check out with the snap on scanner didn’t tell me anything. Shouldn’t a bad CPS throw a code? I can go get the scanner again today if you have an idea but I feel like I went through it all

 

FICM logic?

 

@TooManyToys. anywhere from 10-12v depending on how many times I’ve tried cranking already that day. Fresh charged batteries give me 12v but still little to no buzz

 

I forgot to mention that the truck does puff black and sometimes white smoke when cranking on occasion. Telling me some cylinders have to be firing. Sometimes the truck literally sounds like it’s on the absolute verge of running, but other times pretty much nothing

 

Glad you went to another scan tool. The SCT is NOT a good troubleshooting tool (does not read all codes).

You can not go by sound on rpms. I can not emphasize it enough - you need 150 for a reliable start.

You can have FICM sync and STILL have a bad cam sensor. That said, from what I understood, you tried a known good FICM and it still didn't start.

Usually you will get a code from a bad CMP, but not always.

If you are getting white smoke, and a "slower" crank, AND an injector code ......then that is enough for me to focus on the injector that threw the code.

You could try unplugging injector #5, and then cranking, but again you do not want anything confusing the starting process (ie get a strong crank).

As far as the ICP pressure goes, you really need to report ICP sensor volts when cranking because the CM could be inferring the ICP pressure.

After that, I would probably replace injector #5 if it/they are fairly old.

 

@bismic Okay so I got the scanner back. I am still not getting over 150 rpm.. could that be starter related? Can’t be the cause of the truck stalling while running? I can definitely throw a 6.4 starter on it anyways.

No codes from the CMP, on the scanner it read zero faults while cranking.

I have yet to get another injector code since the one that happened on Saturday. So just black/white smoke with slower crank I guess.

I did not disconnect injector number 5 yet but I did test the ICP volts. Reading .25 at KOEO and came up to around 2.5 while cranking

No injector buzz at all this time while testing. Even with the self injector buzz test on the scanner. Would one injector really cause this? Maybe I stuck a few?

 

You could have a weak starter, who knows.

Plenty of ICP pressure, 2.5 volts is close to 2000 psi.

The few times I have heard of all 8 injectors being stuck is when the oil was grossly dirty/contaminated. An aftermarket oil filter cap and OEM filter contributed in one, and metal from an HPOP was another.

Do you have access to an injector that you know is good? Reason being - see if your truck's FICM and wiring will buzz it.

 

Oil was changed shortly before it sat so that shouldn’t be an issue.. can we rule out metal from
hpop as it seems to be running correctly? I have always used the same oil cap and filter since I bought the truck. I can get access to an injector, still troubling me that sometimes some injector buzz and other times they don’t buzz at all