6.5 Missing like crazy

[The Lurch]

I have a '94 6.5 and it is missing like crazy. We just replaced the motor and we put on a remote PMD. But even after it runs and gets warmed up, it still misses. We have gone through all the injectors and they seem to be fine. When I read codes, it throws almost all the 90's, where the cylinders are off balance. Also, a # 36, which is impulse long.
My worst fear is .......the injection pump.
HELP ME!!!

[Cowracer]

I have a '94 6.5 and it is missing like crazy. We just replaced the motor and we put on a remote PMD. But even after it runs and gets warmed up, it still misses. We have gone through all the injectors and they seem to be fine. When I read codes, it throws almost all the 90's, where the cylinders are off balance. Also, a # 36, which is impulse long.
My worst fear is .......the injection pump.
HELP ME!!!

First off, Dont panic. (aplogies to Doulas Adams). There are some electrical gremlins that may be present.

The cyl imbalance codes are not too worrysome, but the 36 is.

What I would do, is...

Pull your upper intake and cleand and inspect all the connecters under there, like the Optical Sensor plug and whatnot. If you have the radio harness on the OS, unplug it on both ends and try it without it.

Then check all your grounds, including at the batteries.

If you remotely mounted the PMD, there might be a problem with the extension cable. Temporarily relocate it (and its heat sink) back to somewhere on the engine where you can plug it in without the extension.\

Also double check and triple check your injector line sequence on the pump. If you changed motors, I will assume you put your old pump on the new motor? if so, Its really easy to get a couple crossed at the bottom and that will cause a miss.

You also might try a mega dose of a good quality fuel conditioner. Some guys have cleared up a 36 code for a while by doing that.

Lastly, if nothing else seems amiss, get a good DIESEL compression gauge and pull a compression test on all 8 cylinders. Look for any more than a few percent off from the rest.


But, if worse come to worse, and you have to pull the pump, its really not that big of a deal. I just went through it. It was about $700 from SS Diesel supply for a rebuilt pump, and solid day of wrenching to change it.

Do a search under my user name and you will see a post by me with some instructions and tips.

Post back with what you find, and good luck!

Tim

[moondoggie]

Good Day!

Temporarily replace the short black piece of tubing (it's ~ 4" long) that comes out of the top-front of the IP with clear - if any air gathers there, you're getting air in somewhere.
Does it idle fine? Maybe even run OK at low load? Test your LP system, & if you do so, don't just listen to see if the LP is making noise - that in no way means it's actually working. If the truck is idling & you loosen the filter nut (I'm assuming you have the same filter as my 95's do, which I really don't know for sure), fuel should squirt out; if the truck immediately dies, the LP isn't providing fuel pressure during run, so it's either not getting adequate power or it has failed.
As you're aware, the FSD can cause symptoms like this, although their normal fail mode seems to be runs fine, then dies on the highway.
Good hunting - let us know what you find.

Blessings!

[gmctd]

Also - low battery voltage will cause same code - check both battery's for +12.6vdc

Then check the ESO solenoid for same voltage - if low, start with the FSOL fuse in the center

BTW - give my regards to Thing........

[Ooowillow]

What did u find wrong with the truck

[trbankii]

Looks like he hasn't been on the forum for seven and a half years...