5.9 dying when warms up

[wrighttruck]

I have a @006 f650 with the 5.9 cummins in it with Allison automatic. When I start the truck when cold it will start with no problem. As the truck warms up it starts to loose power. After driving 2 to 3 miles it will slow down to max speed of around 15 mph. If you lift your foot off the throttle it will die instantly. To get the truck to restart you have to let it sit for few minutes without any attempt to start. If you can keep it going the truck will start to run better the farther you go. If you make it 20 miles the truck will almost run as it should. If you leave it idling to get to the bad running part it sounds like it is running low of fuel because it is missing. It also does produce excessive black smoke. I have replaced the low pressure pump, cp3 pump, and the common rail with new sensors and relief valve. The truck has gotten progressively worse since I bought it 2 months ago and is about unusable now unless I leave it running around the clock. Any suggestions?? I did take my truck to shop in the next town for troubleshooting. They are the ones that told me to replace cp3 pump. Truck had code for low supply pressure and low rail metering pressure.

 

[cerberusiam]

Start be re-TQing the cross over tubes and checking injector health, you have done every thing else in the fuel system. Assumed you have checked for oil contamination from a cracked injector?

 

[wrighttruck]

I am not really sure how to check injector health. I have not really checked oil for contamination but have been keeping an eye on oil level. I will try checking tube torque.
Thank you

 

[cerberusiam]

You need to run a contribution test on the injectors and a return flow test to get an idea what shape they are in. You didn't say how many miles or what the filtration setup is, but, as early as 150k you can have problems with the injectors.

 

[wrighttruck]

My truck as the factory spin on filter. I can look tomorrow to check micron rate on the filter. The truck is just shy of 440,000 miles. I have had the truck just over 2 months so I can tell for sure any work done to the truck by previous owner{s}. The only thing I was told that it had recently had a new turbo put on the truck previous of my purchase. It has the 16 pin deutsch style connector for the computer to the engine. I have to try and drive the truck to a neighboring city for someone to be able to do any diagnostic work. I got hit with $300 bill and was told it needed a cp3 pump that did not fix the problem. I'm just leary of going back and forth and feeling like I'm just replace parts.

 

[cerberusiam]

If injectors have never been touched and there aren't at least 2 filters on the truck they are a likely candidate. If you are not getting any obvious codes and CEL's that is a place to start. It is possible the transmission is causing the engine to derate in that configuration but would expect to see some indication.

 

[wrighttruck]

I finally got the truck fixed!!! I bought a complete set of injectors from Bosch and updated flow tubes from Cummins. All the injectors did not look good but number 6 was horrible. The flow tube had to be pulled with quit a bit more effort than any of the other 5. My problem is finally gone and I'm back up n running. Thank you for all the help!

 

[cerberusiam]

Glad you got it running right. Easy fix, just not cheap.