'96 6.5 Sub with poor throttle response and lacking power.

[kulwap]

I have a 96 sub that was running poor about 1.5 years ago. I had done some work on it before including installing a remote PMD, and later a new IP, new glow plugs, new injectors etc...

With the most recent problems eventually I thought it was the PMD and I replaced my Heath remote kit with a SS Diesel kit. When I went to install the SS kit, my electrical harness did not reach the PMD (because of how I routed the harness when I had replaced the IP 6 years ago). I pulled off the intake manifold etc... rerouted the harness and at the same time I was checking out my single thermostat. I ended up cracking the thermostat housing and I could not find a replacement so I bought the double thermostat kit, but by the time it arrived and I had a chance to install it, snow was on the ground here in Spokane. About 2 months back I finally got around to installing it, bought 2 new batteries and got the sub to run. Thing is it idles OK, but lacks throttle response and really lacked power trying to get up a minor hill on a local country road. I am out of ideas and I don't want to spend the money to replace the IP. I should say too that about a year ago I had taken it to a local independent diesel repair shop and they quoted me $3600 for all the work including a new IP etc... AND they said something was wrong with my transfer case but the kicker besides the sticker shock was that my sub is a C2500 not a K2500. Thanks in advance for any suggestions. If I can't get it to run right I might be putting it up for sale!

[racer55]

I would make sure the lift pump is working first,open the water in fuel tee-valve with the engine idleing and if it stalls the fuel filter is plugged or the LP is dead.

Second have the TDCO timing setting checked/corrected,was the timing relearn done after the IP install?

Were you aware that the Heath PMD has a 7 year warranty?Or had it already expired?

I would not mount the SS PMD on the intake for any reason other than to take a picture for warranty,once that is done I would relocate it to an area outside the engine bay using the Heath extension harness for the longest life possible.

[6.5 Detroit Diesel]

Were you aware that the Heath PMD has a 7 year warranty?Or had it already expired?

I would not mount the SS PMD on the intake for any reason other than to take a picture for warranty,once that is done I would relocate it to an area outside the engine bay using the Heath extension harness for the longest life possible.

This ^^^ :D

If you are still looking for power, get the GL4 program from Heath. That will add some juice. Maybe open up the exhaust too....

[Robyn]

For sure, the fuel filter and the Lift pump are suspect.

If the filter is plugged these things will run horrible.

Replace the filter and be sure the lift pump is working. With the engine at idle, just open the fuel drain valve up front, fuel should come out readily and the engine should not die.

If no fuel coms out or the engine dies then the Lift pump is not working.

Is the SES light on ??


Missy

[kulwap]

Thanks for the input. I will check these items and repost.

[kulwap]

OK, so I replaced the fuel filter and purged the air and any water from the lines. The sub still idles fine, and in neutral I can rev the engine up to about 3500 RPM without a problem. With no load it appears to run fine and respond to any throttle input. Under load (ie driving) it still seems to run fine, it doesn't miss but it does lack power. I noticed this time while driving it that it almost seems like a transmission problem. I can floor the pedal and it doesn't want to downshift and accelerate. In fact in order to get it to shift (if I have it floored) I have to lift my foot off of the pedal and as soon as I do it shifts (and shifts hard), but still does not accelerate. It just has NO power and struggles up hills, even at 25 miles an hour in the neighborhood the sub struggled up a relatively steep hill and crested the top at just under 20 mph. Trying to manually shift it has no affect on it and does not show any improvement.

As for the lift pump. It appears to be fine, fuel does come out when I open drain valve (I don't know if I would describe it readily or not, but it does not die either), I had changed it out probably about 2 years ago so I had maybe 6 months of intermittant run time on it. Still I am not sure, I can hear a "clicking" noise that seems to come from the pump (I am deaf in my right ear so I have a hard time locating the sorce of noises) when I crawl under the sub and put my hand on the lift pump when the engine is running I can feel the same click that I hear. While driving and trying to accelerate the clicking is more pronounced. I saw this post (http://www.thedieselpageforums.com/tdpforum/showthread.php?t=39445) and I am wondering if it is my OPS or maybe the LP (because of the noise) or both.

Yes the SES light is on and I get one code (P0251).

Any more ideas?

[JohnC]

Does it have clean fuel? The screen on the tank pickup could be clogged. Put a fuel pressure gauge on the water drain line, open the valve and drive it. If the pressure goes negative, you have a fuel delivery problem.

How's the air filter? Boost pressure?

Otherwise, check the injection timing with a scanner.