94 6.5 turbo diesel

[david beesley]

I have completely redone my 94 6.5 turbo diesel. when it started acting up I thought the transmission went out. put a new one in, rebuilt the motor, and I still have the same problem. it starts but when I try to accelerate the rpms surge. please help me figure it out.

 

[ak diesel driver]

Sounds like a PMD or IP issue

 

[NVW]

Sounds like a bad Injection Pump

 

[Husker6.5]

Without more info, like what all was replaced in your motor rebuild, miles on vehicle, I would say classic symptoms of IP starting to wear out. Hint: If it is the IP going out and you choose to do nothing about it, not only will the light surging get to the point that it is 100-200 rpm swings and noticeable when going downhill as the TCC unlocks and relocks, but the bad IP WILL eventually take out your new automatic transmission with it due to the TCC going through those multiple unlock-lock cycles when going downhill eventually wear the clutch out and pumps your transmission full of clutch friction particles and fine metal shavings, if burnt transmission fluid from the heat of the TCC slipping/cycling doesn't do it in first. Speaking from experience, a new transmission and IP at the same time is a dent in anyone's budget.

 

[Pickseed]

What about fly by wire throttle?

 

[Will L.]

Welcome. Sorry you did t find us before spending all that money.

I agree with the others it sounds like a fueling problem. Before spending any more big $, I say cover a couple of basics.

With the engine running, open the brass drain valve on the front of the engine by the thermostat housing. See If it dies. It should not.

If it doesn't then replace the fuel lines going from the fuel filter to the injector pump 5/16" and the return line coming out the front of the injection pump 1/4" with clear line (hardware stores sell it by the foot).

Your looking for bubbles in the lines. If you have bubbles going into the IP, you are sucking air in and need to fix he leak. If it is clear of bubbles going in, but has bubbles coming out, time for an IP. No bubbles in or out, then buy a new pmd from Leroy. It does not mean ip is good, just need to do basics first. There is no test other than replace with a known good one. They are not considered reliable anyways- you need a spare pmd just like a spare tire.

I am assuming you ensured all the grounds that are on the engine- especially the ones by the tranny dipstick are in good condition. A bad ground will not let the pmd work properly.

 

[Husker6.5]

Also, again not knowing mileage on the vehicle and everything that you have or have not done to it, ascertain whether or not your lift pump is operating. Not just running, but pumping fuel up to the FFM. If the lift pump goes out, the IP will run fine at idle, but when you accelerate the IP tries to suck fuel (something it is not designed to do) all the way from the tank and this will cause starvation surging, too. This will also eventually destroy your Injection Pump if it has to try and suck fuel for very long. It can also be something as simple as the filter sock in the fuel tank is plugged up, too.

Filling in your vehicle info in yor signature helps tremendously.