Head gasket change, no start, P0192

greiswig · **Posted:** Wed Nov 05, 2014 2:13 pm

gmctd,

Thanks for the congrats. This group has been really helpful.

I don't know whether the FPS is a resistive sensor or not, so maybe this wouldn't be helpful at all, but I wonder if it might not be useful to publish a baseline set of multimeter readings between the pins on a known good sensor under 1 bar (uninstalled) and then installed on the rail after the engine has run, but been left for awhile to let pressure settle?

gmctd · **Posted:** Wed Nov 05, 2014 4:02 pm

The Fuel Pressure Solenoid is normally closed to prevent rail pressure bleed-off - this prevents a DTC with 'no-start until rail pressure normalizes' conditon - I'm not currently working on the KJ, but have considered inserting a 0~10000psi gage inline with the supply pipe from the CP3 to show any excessive bleed-down

Also, prollem being, actual measured pressure exactly equals ECM desired pressure from idle rpm ~6000psi to 1000^rpm ~21000psi - P019x don't compute in my math\logic package

The DTC immediatly reflags after clearing, and engine rpm is limited to 3000

rancherman · **Posted:** Wed Nov 12, 2014 10:28 am

gmctd wrote:

It has to be of emminently greater importance on the 6-cyl CUMMIN(no g, eh)S engine and later V6's with 360/6 injection sequence of 60-120-180-240-300-360 - 3-cyl CP3 pumping pulse is 120-240-360, which could conceivably cause some co-event commotion in the fuel rail

Anyhow, my bad on the rail bleeding mis-info causing lost time - your head gasket thread subject plainy indicated complete aparting of the fuel injection system, which would require full bleeding of the system, yet I was addressing partial disassembly which would require little-to-no bleeding - feel free to ignore that earlier input

I was also mis-thinking some other fault becuse mine starts and runs with same DTC, which, due to not currently working on the KJ, I have not as yet solved - even gots a new not-installed FPS on the table, just waiting for cooler weather to rejoin the fracas

So, congrats on your perseverance in moving to the next stage

We've fooled around with the pump settings on our fleet of cp3'd rams, and can say one thing: hardly any performance difference in the amount of adjustment available.
But what we HAVE found, is NOISE. or lack of. I'm talking about the hydraulic harmonics barking through the pump and rail.

you're right on the 120, 240, 360 timing. Exactly what a 6 cylinder needs.... Just as our Jeeps fire every 180 degrees, our pumps are 'geared' for it.
The cp3 pump 'fires' all 3 of it's plungers at the same time, but it still has 3 impulses per pump rotation. There is an impulse every 180 degrees of crank revolution. That's where the different sized pulleys come in.
That is why it takes several rotations to align the 'timing' mark on the pump again.. Odd number'd cam in the pump, versus the even numbered amount of cylinders. Nonetheless, the pump is squirting once per 180 crank degrees.
Impulse 1 coincides with cylinder firing #1
impulse 2 coincides with cylinder firing #3
Impulse 3 coincides with cylinder firing #4
(Pump now has rotated 1 revolution...but engine still has one more cylinder to fire)
Impulse 1 now coincides with cylinder firing # 2
and so on she goes... until the timing marks align again.

gmctd · **Posted:** Wed Nov 12, 2014 2:55 pm

Ok, correct - stated confusion was resulted from having slept some since back then - back in the game, now, after reviewing these threads.................

CP3 Injection Pump description
- viewtopic.php?f=5&t=25047&hilit=bosch+cp3

CRD Injector pump update....................
- viewtopic.php?f=5&t=58007

Appears timing requirement is chiefly noise-related, tho in a smaller-displacement engine could have some (d)efficiency effect - much info therein with pics

rancherman · **Posted:** Wed Nov 12, 2014 5:05 pm

gmctd wrote:

Ok, correct - stated confusion was resulted from having slept some since back then - back in the game, now, after reviewing these threads.................

CP3 Injection Pump description
- viewtopic.php?f=5&t=25047&hilit=bosch+cp3

CRD Injector pump update....................
- viewtopic.php?f=5&t=58007

Appears timing requirement is chiefly noise-related, tho in a smaller-displacement engine could have some (d)efficiency effect - much info therein with pics

Very possible! (efficiency wise) I'd like to think, if something is 'ringing like a bell'... there has to be stress somewhere! Believe me, they really bark when 'off'.
There is quite a few older posts that think 1 of the plungers, or impulses per se, are for recharging the rail.. which would 'even' out the 3 piston pump/ 2 cylinder (per rotation) firing requirement. Simply not the case. It's 2 impulses per rotation of crank. All day long.

greiswig · **Posted:** Thu Nov 13, 2014 9:01 pm

Quick update: P0192 was indeed the FPS. Got a new one and installed it, and all seems to be well. I'll need to put some more miles on it and temperature cycles before I'm fully confident that the head change and everything are going to last and hold, but it seems good for now. Just in time for some winter weather to hit us here in the PNW.

RockyMountainYote · **Joined:** Sun Oct 20, 2013 8:32 pm **Posts:** 77

Glad you got it sorted out. Sorry It took me so long to get back to you about my extra fuel rail.

Head gasket change, no start, P0192

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