05 CR won't start, very low rail pressure, did fuel return test.....

texascadillac42

texascadillac42

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Customer brought an 05 CR (250,000 miles) to me for a hard start/no start condition. He bought the truck at an auction and it looks like its seen better days. It appears to have had gauges on it at one point so I'm assuming its been turned up in the past. As far as he knows now it has stock tuning.

He said the truck became progressively harder to start, finally requiring ether, then required being pulled to start.....

Once it runs it will stay running, drive ok (has a slight miss around 1200rpm and up) and restart ok as long as it hasnt sat too long. If you let it sit overnight, it will not start again.

My scanner shows that when it is running and then shut down and restarted, the commanded RP versus actual RP is very close, basically identical. When the truck does not want to start, actual RP is very low, around 1000 psi. I know this will not be enough, so I pulled the fitting out of the back of the head to check return flow, and with a buddy cranking it over, there appears to be no fuel coming out of the head.

I did notice that the PRV has been plugged with what appears to be a lug bolt from a VW Jetta.....

The truck has an AD 150 on it, and it has 15psi going to the CP3, which was checked with a mechanical gauge. Injectors are clicking and have power going to them with the key on. This is the first CR I've worked on/diagnosed and I'm not 100% sure where to go from here...

Thanks for any help.
 
I just went through this on my truck 2003.

I had a couple crossover pipes/ tubes that were leaking and a bad PRV.
You obviously dont have the PRV problem but what about cross over tubes?


If your getting 15psi to the CP3 then I would go with the CP3 maybe?

I'm pretty new to the common rail engine myself so if nothing else I'll follow your thread to learn more about these things.
 
I was hoping that the fuel return flow test would tell me if I had a crossover tube or injector issue. The oil level is not higher than normal, and does not smell like diesel fuel. I may order a cap from Cummins so I can block off injector lines one by one to see if my cranking RP changes....
 
Performed an FCA test following the instructions here...

http://www.genosgarage.com/helparticles/GG_TS-FCA.pdf

and the solenoid seemed to be operating consistently with a good "click" as power was applied to it. So I will rule that out for now. Aside from bad injectors/tubes or the possibility of a failing CP3, the overflow valve in the CP3 is the only thing left that could be bleeding pressure off, correct?
 
Not satisfied with the initial fuel return flow test I did, I did it again. This time, instead of just watching for fuel dripping out of the hole in the back of the head, I found some fittings in my shop that let me thread into the head, then run a hose into a cup, and also block off the line that was originally secured to the head.

With less then one minute of cranking I have right around 100ml of diesel. I know spec is 90ml for one minute so it looks like I am over the spec. Injectors will be coming out tomorrow and sent off to get tested.

The problem with my original test is I had to much leaking from the fitting/line that was originally hooked to the head, so I couldn't tell where fuel was coming from, the head or the line.
 
texascadillac42 said:
Customer brought an 05 CR (250,000 miles) to me for a hard start/no start condition.
He said the truck became progressively harder to start, finally requiring ether, then required being pulled to start.....
Once it runs it will stay running, drive ok (has a slight miss around 1200rpm and up) and restart ok as long as it hasnt sat too long. If you let it sit overnight, it will not start again.
When the truck does not want to start, actual RP is very low, around 1000 psi.
Injectors are clicking and have power going to them with the key on.
Click to expand...

Hard start on a CR is usually a high-pressure fuel leak - most of the time from a poor seal between the crossover tube & injector, caused by improper installation.
Using thumb pressure to seat an injector w/o the crossover tube removed is enough for the body to clip the tube end - feels like the O-ring seating in the injector bore, but the hard body just nipped off a bit of soft tube end.
Even a tiny amount of material removed is enough to prevent the CP3 from generating at least 3Kpsi in the rail at starter RPM... <3Kpsi = no command to fire solenoids from ECM.
Best practice is to always remove connector tubes completely for inspection & repair/replace as required - never had a tube tip yet that couldn't be refinished successfully unless the injector was installed via dead-blow.
High-pressure fuel line ball-seats are occasionally the culprit, if they've been overtorqued.
 
Unfortunately I don't think we will ever know how this truck is going to turn out, customer doesn't want to deal with it, and is selling it "As-is" and moving on to an 07 5.9.
 
I had a similar issue with mine last year and it ended up being a a bad rail pressure sensor, good luck
 
texascadillac42 said:
Unfortunately I don't think we will ever know how this truck is going to turn out, customer doesn't want to deal with it, and is selling it "As-is" and moving on to an 07 5.9.
Click to expand...

More info on the truck please. Im interested in buying it.
 
Just to give an update. Customer decided not to buy the 07 truck, and is now fixing this one. Injectors were pulled and sent to Garmon's for testing. I should hear back next week and hopefully get it back on the line.
 
Garmons said 4 of the 6 injectors were returning way too much fuel. A set of 6 new injectors is going in the truck and we should be back in business.
 
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