Electrical gremlin in pull truck

[golfer]

you're not checking gear run out...you need to be checking cam gear end play.

but on the other hand...if you have an rpm reading on scan tool (or scope)...why are you even dicking with the CPS/CPS wiring at all?

 

[ibestroken]

Because it keeps throwing the 0344 code. Guessing its intermediate. That's why I figure a wire or something may be rubbing or cut. I'll have a chance to check it out again starting tomorrow

 

[ToMang07]

The CPSs you pulled....any damage on them, where they go into the block?

 

[golfer]

Because it keeps throwing the 0344 code. Guessing its intermediate. That's why I figure a wire or something may be rubbing or cut. I'll have a chance to check it out again starting tomorrow

every 7.3L in the universe that cranks for an extended period of time without actually starting will throw a CPS code...

ie..do an injector change on a truck...alllll that cranking to get the LPOil and HPOil system primed will always throw a CPS code...but it has nothing to do with the actual CPS...it's just in the software.

what I'm saying is that if you have to crank the *** out of the truck to get it to start..that's why you're getting the CPS code not because there's (likely) anything wrong with the CPS/wiring/etc...particularly since you've indicated that you actually HAVE AN RPM reading ON a scan tool...whilllllle cranking....even when it won't start...right???

 

[ibestroken]

Yes I have rpm on scan tool while cranking. I can clear the code when I do get it to run and when it starts acting up and shuts off that's the code it throws before it dies. So you're telling me that doesn't mean squat? Honest question

 

[golfer]

Yes I have rpm on scan tool while cranking. I can clear the code when I do get it to run and when it starts acting up and shuts off that's the code it throws before it dies. So you're telling me that doesn't mean squat? Honest question

if you have rpm on the scan tool (allll the time, every time while cranking; starting or not starting), then there's nothing wrong with the CPS, or the wiring to PCM from the CPS, in my opinion.

if you have a 'scope..what are you seeing 'fall out' when the truck dies?

FDCS, CID, CPS signal(s)?

I'm more interested in what you mean when you said "when it starts acting up and shuts off"...

like it 'acts up' in what manner before it dies?
CEL/SES comes on prior to shutting off?
or runs rough (how so) before it dies?

what is the actual code being stored in the PCM? is a CEL/SES light being illuminated prior to the engine turning off??

it sounds like the cam signal may be dropping out...possibly from cam/gear walk...but maybe not if you abso-***king-lutely have rpm on scan tool under all cranking conditions.

have you checked your vRef voltage(s) on all 3-wire sensors?

one bad sensor can draw down the vRef enough to cause the (only important one) CPS signal to drop out.