06' won't start... need guidance

We have had a similar scenario, that ended up blowing my mind with the final fix. We started with swapping in a good PRV and Rail pressure sensor from Larson's 06 truck, no change. Then we did a return test on injectors and it was at the max of the acceptable margin, so we installed a new set of Exergy 100hp injectors with no luck, so the only thing that was left was the cp3... installed a new sportsman cp3 and still had no rail pressure.

After scratching our heads, we pulled the complete rail assembly and lines off my brothers truck and swapped it on to test and bam, rail pressure. Mind blown. It had no return to the PRV and injector return rate was good and no external leaks, but somehow, someway the actual rail was the problem. I'm still to dumb to wrap my head around how it could effect it, but I took the chop saw with a metal blade and cut the rail in 3 pieces before scraping it to make sure nobody decides to install it on anything! Lots of wasted time/money on that truck. So I would recommend finding another 06 truck to swap parts with before spending the customers money on a completely new fuel system.

Lavon
 
I have had a truck that we tried everything and found in the end it was a bad rail, that evidently had a crack internally accross the return. Mine was on a 6.7 so like lavon said it doesn't make sense how it could even be possible with 5.9 rail.
 
That's crazy, Lavon. Rail assembly with sensor isn't too bad, I'd def give that a try.
You can use BB's to cap off all 6 injectors at the rail. Pull line off, set BB on rail, snug line back on. Be careful doing it.


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I would want to see rail psi somehow, before going further. Cap em off, get rail psi, then you narrow it down.


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LAmiller said:
We have had a similar scenario, that ended up blowing my mind with the final fix. We started with swapping in a good PRV and Rail pressure sensor from Larson's 06 truck, no change. Then we did a return test on injectors and it was at the max of the acceptable margin, so we installed a new set of Exergy 100hp injectors with no luck, so the only thing that was left was the cp3... installed a new sportsman cp3 and still had no rail pressure.

After scratching our heads, we pulled the complete rail assembly and lines off my brothers truck and swapped it on to test and bam, rail pressure. Mind blown. It had no return to the PRV and injector return rate was good and no external leaks, but somehow, someway the actual rail was the problem. I'm still to dumb to wrap my head around how it could effect it, but I took the chop saw with a metal blade and cut the rail in 3 pieces before scraping it to make sure nobody decides to install it on anything! Lots of wasted time/money on that truck. So I would recommend finding another 06 truck to swap parts with before spending the customers money on a completely new fuel system.

Lavon
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Thats interesting. did you guys have fuel coming out the overflow? Because I have none. we know the pump makes pressure as I sent it to Todd @ TC Diesel to be tested. The only thing we have Thrown at the truck was injectors, which the truck has 170k so it probably isn't a bad thing. I pretty much knew if we had them tested they would come back out of spec, whether causing the issue or not. The Rail sensor and PRV were swapped from a known good truck.

If a rail fixes it, I will be scratching my head for sure.... considering there are no visable leaks and no fuel returning from PRV.

The other odd thing is this truck will run when started on ether.....as long as you keep some throttle applied.
 
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I wonder if the rail has just enough of a crack in it that it is allowing pressure to escape, but so small that fuel cant pass?

When I re-read it it doesn't make sense, but obviously it's bleeding pressure off somewhere?
 
I had a similar problem, mine had a bad wire right at the rail sensor. When I unplugged it and tested for voltage it was fine but when the wires were plugged in it had enough bend/stretch to loose continuity.

Have someone crank and watch rail pressure well you wiggly wires. I'd check the whole harness.
 
One of our new Injectors was returning a ton of fuel. the Original Issue was in the injectors.
 
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