Hey folks,

I just scored (I think it's a score anyway, remains to be seen) a 1994 K3500 4x4 with the 6.5 Turbo and a 4L80E. It has the stalling issue (PMD I assume) and the fuel line going to the bottom of the fuel filter is leaking at the moment. This is my 1st 6.5, I have been screwing with the 6.2's for 10 years or so.

Here is the plan, tell me if I am barking up the wrong tree and/or add anything I am missing.

PMD Replacement/Relocation/#9 Resistor. Relocate to behind the bumper.

Change the oil pressure switch, and install the relay between it and the pump.

Replace the lift pump (WALBRO), and the line from the pump to the filter. Change filter.

Change the wastegate controller for a manual version.

Dump the vacuum pump.

Upgrade to the Dmax fan.

4" exhaust.

Did I miss anything important? I really want the truck to be rock solid dependable. I am setting it up for my dad, and he is pretty weak on diesels.

Thanks!

Offio

 

Use only AC Delco or GM electrical parts.

I would test the OPS before changing. Once you do the lift pump relay upgrade, Your OPS will last forever. I would save time and money by not messing with the OPS.

aRE YOU MAKING YOU OWN LIft pump trlay upgrade? If so, I would make it like Leroydiesel.com makes his. Plug and play, with an on off switch to prime the fuel filter or doagnostics

I would add a fuel pressure gauge.

 

Thanks for the tips!

Yeah, I saw a video with the Leroy setup, and was planning on putting in a push button for priming...oh, yes, I am making my own relay upgrade. I was an Aircraft Mechanic for 12 years, with a specialty in electrical systems...before switching over to wind turbines for a while. Wiring doesn't scare me.

Why test the OPS before changing it? I agree the load will drop alot, but it still seems like a good idea. Oh, I probably forgot to mention the truck has 333K miles on it...engine and trans were replaced about 150K ago. So, I figured it was just cheap insurance to change the OPS and be done with it.

Cheers!

 

Don't do the cutting and splicing like some of the schematics online show. Make it plug and play like leroy's.

I used toggle switches instead of a momentary switch. I never have an extra hand to hold a button when priming the filter or doing diagnostics.

I think Leroy has also got away from the push button and gone to an on/off switch. I would not buy his previously because of that. Why buy something when I am going to modify it to what I want?

I would also do the prime feature. I think that is also something that leroy has started including. I think you used to have to ask for it.

Why change the OPS if it's good? With the relay upgrade it might outlast the truck.

I've bought so many bad new parts - parts that didn't work from the gitgo and parts that did not last a decent amount of time, that I have shied away from changing most parts in a proactive manner.

Seems a good old part will last as long or longer than most new parts anymore. And I shop for quality parts as I don't have time to do things once, much less twice.

With the relay the OPS only needs to put out enough juice to trigger the relay - not much.

Even when completely trashed they most often still put out enough juice to trigger the relay - so there isn't much reason to waste you money there.

The part that sends the signal to the oil pressure gauge rarely goes bad

If you're rich and just want to spend money, I would take a donation on the 1200 trees I have to plant.

I have posted a link to the connectors needed to make your harness plug and play someplace on the Wide Wide World of internet. I think I posted it on this site also.

If you find a link to the connectors, post the link to this thread for others that find it in the future.

If you are in the rust belt, I would go with the stainless exhaust. Give Leroy a call or Walt at SS Diesel. Or Heart Throb Exhausts in Minnesota - I don't care much for Walt or dealing with him.

I had my down pipe rot off the aluminized system the previous owner put on my 94.

I demand a removable down pipe. Heart Throb has the connector you can add in or you can install a 4 bolt flange like some of my vehicles have.

The ball and socket connector from down pipe to the exhaust is an easier deal in my opinion. But the bolted flange isn't bad either

While you are doing the D'Max fan, you might want to consider the year 2000 water pump - that is supposed to be the best option.

If you are doing the manual waste-gate controller i would also add a gauge pillar. With fuel gauge and boost gauge at the minimum

I prefer to just run with the OEM vacuum system.

But the manual system is less problematic.

You could also do the fed the beast mod while you are at it.

The PMD's on the IP seem to last as long as anything. They are just a pain to change out there. They all go bad eventually.

Add your new PMD inside the bumper and if that cures your issue, then you are good to go.

I use the license plate bracket bolt to mount the PMD heat sink. I orient the PMD so the plug is inside the bumper nostril, but pointing towards the nostril.

I mount my spare PMD's inside the other nostril. So all I have to do is switch the extension cable if I have an issue.

In an ideal world I would have 2 extension cables run and do the switching under the hood if need be. But I cannot afford 2 extension cables for every vehicles.

Buy only made in the USA extension cables - leroydiesel.com has them.

For dependability add the extra grounds and do the battery bolt mod. and upgrade the battery cables - a lot of older cables are corroded on the inside where you can not see the damage.

I add an extra OEM alternator cable, from a salvage yard or where ever from the alternator to the battery that does not presently have an alternator cable going to it.

On a 1994 and older - upgrade the cable going to the lugs on the firewall - the OEM is not very big.

For grounds I add a ground to the stud at the back of the engine - I have seen that stud lose connectivity to the block several times,

I add a ground to the battery box bolt on the passenger side, I add a ground to the frame by the starter.

I add a ground to the PMD heat sinks.

I add a ground from the heater blower ground to the dash mount bolt just inches away.

Might want to check out the heater blower while you are there.

I use 1 1/4" Allen screws for the battery bolt mod. You have to cut any taper off then end of the Allen screw.

I got battery cable ends and other connectors from Waytekwire.com

 

3 other mods I do for dependability and longevity are the Fluidamper, Amsoil or FS2500 bypass filters and Amsoil 5w30 heavy duty diesel engine oil.

I like the filters mounted under the hood. Just because I have done some stupid damage to things under the vehicle.

I had a brake flex line ripped off by bean stubble, I had a flat tire from bean stubble. Had other thing underneath ripped off or damaged in ways I would never even think possible.

I install a T in the return line from the engine oil cooler to feed the bypass filter and return to the engine fill neck

 

Check your T stats as well make sure they are AC Delco they have a design feature for porting coolant correctly that provides better cooling, also "DEEP CLEAN" the external fins/cores of Rad & AC you would be surprised how much crud is packed in there, and kills airflow across them. Proper cleaning with garden hose pressure only so you don't bend over the fins takes about 3 hours to do correctly.