Stumped! Help!

[racetruck]

So, truck broke down a few weeks ago and it ended up being a bad IPR plug. Replaced it, ran great, few nights ago did the same thing. Changed the plug, IPR valve, ICP, and still won't start. Hooked it up to scan tool and the ICP read 2700 which is more then enough to start. Super abnormal. Any ideas? We checked idm and it was not that. Thinking its a bad upper motor harness, opinions?

 

[G Racing]

If you have icp then you need to look at your cps, injector harness, check your fuses, can you buzz test your injectors?

 

[racetruck]

We checked fuses, they're all good. Changed CPS, haven't checked injector harness yet, I found an entire engine harness for around 50 bucks that I can pick up and try.

 

[golfer]

if your scan tool is reporting "2465psi" then that is a bogus number, and you (most likely) do not have actual pressure in the HPOil system.

monitor ICP while cranking....see if it ramps up gradually while cranking..or sits low (sub 300psi) for a while then instantly spikes to "2465"...

if it's the latter....you do not have actual pressure in the system...and the PCM is simply reporting a default value to the scan tool after extended cranking (and no real mechanical pressure being made).

list of modifications on the truck?
miles?
recent work performed?

 

[racetruck]

So would that be a bad hpop? Or bad harness? No mods. 193,000 miles. No recent work performed on it either.

 

[golfer]

no...it simply means that you aren't making enough (mechanical) pressure to fire the injectors.

as to which component is preventing the pressure to build?
that's called diagnostics.

IPR
IPR o-rings
HPOP
injector poppet valves
injector o-rings
any number of HPOil fittings and o-rings on the head &/or under the valve covers.
even a LPOil issue (preventing the HPOP from having any oil to do anything with)...will allllll have the same issue.

I'm most likely leaving a few items out..but if you aren't making ICP pressure...that only explains the no start...it doesn't tell you which part(s) to replace.

 

[racetruck]

So could it still be a harness?

 

[golfer]

doubtful...but at this point I don't see that you've even verified WHAT the ICP pressure is..you're going off what (seems to be) a bogus/default value displayed by a scan tool.

you need to first monitor what your ICP pressure IS WHILE CRANKING...either with a mechanical gauge on a cylinder head...or by ignoring the scan tool (assuming it IS going into default for 'ICP' pressure)...and checking voltage with a multimeter (while cranking)

1v ~~ 750psi of ICP (center pin on ICP sensor, plugged in, while cranking)

 

[racetruck]

Well when it broke down the first time it defaulted. It acts the exact same way now. Its reading 2500 while cranking, which is obviously wrong. I'll have to try the voltage thing.