I've got a 1993 K3500 dually with a 6.5 manual. The issue is it intermittently dies or just gets rather doggy. Other times it runs like a champ. I've already rebled the fuel system, cleared the return line, and replaced the line pump, injectors, timing chain and gear set. I'm not sure what else to do at this point. The boost gauge says the old Borg Warner is throwing 10-12psi at it so I think it's alright. Truck has about 165,000 on the clock with minimal blowby. Any help is appreciated!


Mods: 4in straight pipe, 2.5 crossover, SS diesel supply alternator,waste gate, and intake.

 

My first guess is the Injection Pump. Maybe there is too much wear in there with the rotor, pistons, and housing.??

 

The pump probably has about 60k on it. I guess it could be worn is there a good way to check the pump?

 

When it is doggy pour some water over the IP and note improvement.

Also replace the IP fuel return line with clear diesel rated tubing and watch it when the truck is parked safely and idling looking for bubbles-they indicate an air leak in the supply side between the fuel in the tank and the LP.

 

I've got the clear return line on the truck currently. There are a few bubbles at start up and that's all. I will try the water when able.

 

Bubbles at startup could be due to a leaking water in fuel or fuel heater O-rings?

 

I'm going to replace the soft lines post filter and check the sock filter in the fuel tank this weekend. I'll check for water in the tank then. What are fuel heater o-rings and where are they located?

 

Fuel heater O-ring is in the bottom of the filter housing and the water in fuel sensor is on the back of the housing-both have O-rings that can and do leak when and that shows up after it has sit for some time-the fuel that leaks out gets replaced by air.

 

Nice! I'll check that out too I was going to pull the housing anyway and look it over. I appreciate it!

 

Thanks for the help on the old truck the o-rings seem like they may have been the issue.