New diesel owner - 6.5TD - maintenance questions

Blaze

Blaze

The Jeeper Reaper
Joined
Aug 9, 2005
Location
Wake Forest, NC
OK, so I have owned tons of gassers, but this is the first diesel I have ever owned. It is a 6.5L turbo in a 98 2500 Chevy truck.

I've heard to change the oil and filter every 4k miles without fail. I'm guessing that is a correct statement.

What other maintenance do I need to keep up? I know there is more than a standard gasser, but not sure exactly what and at what intervals. I know fuel filter and stuff like that, but how frequent?

The truck has new heads and head gaskets, new injectors, new PMD (relocated), new fuel solenoid, new thermostat and all that stuff, etc.

2014-05-31 17.54.52.jpg
 
Yes, change the oil every 4k miles. Diesels bypass the soot straight into the oil. Don't get too alarmed when you change the oil and check it in 100 miles and find it just as black as when you changed it.

Keep the fuel filter changed, I try to change mine at the beginning of every cold weather season just to be safe. Also, keep a spare in the vehicle. Not uncommon to have one clog up on the road due to bad diesel fuel. Had it happen to me once. If you have the factory filter system, I have extra filters I need to get rid of - can make you a deal....

I see the PMD is already relocated - very good thing. These electronics don't like the heat, of course. There are heat sinks and extention harnesses available on-line to relocate it. Most 6.5ers put it right behind the front bumper. GM/Stanadyne mounted these so, in theory, the recirculating fuel would keep the PMD cool. Didn't work and gave the GM diesels yet another bad rap in the 90's. I would also keep an extra PMD in the vehicle. These can go bad at anytime and they can be changed easily once you relocate them. A bad PMD can do all kinds of crazy stuff with the rpm's! I'm getting ready to Ebay the extra one I have if you're interested. Already mounted to the heat sink and includes extension harness.

Any hard starting issues are usually attributed to glow plugs or injectors. Cheap parts compared to Dmax's are any other of todays HP diesels.

Those are the main items. Get on the diesel forums...The Diesel Page is my favorite - LOTS of mature, experienced advice there. The Diesel Place is another good one. The Diesel Page has really helpful books you can purchase that has R&R procedures for most everything 6.5/6.2 and other maintenance info. I highly recommend them.
Had my 6.2 83 Sub going on 20 years. Also have a 86 6.2 K5 and a 94 6.5 K1500 (broken trans - planning to sell). Lots of miles on all of them - 340k on the Sub, 295k on the K5. Let me know if you have more questions.
 
Thanks a ton. I'm pretty sure I still have the factory fuel filter setup, let me verify. Would definitely be interested in those filters.

The PMD is on a heat sink behind the rear bumper. The guy also gave me a spare one that I keep in the glovebox.

The truck starts really easily, fires right up with no problem.

I'm glad you said that about the oil, the guy had a log of when he changed the oil and it showed he changed it 400 miles ago. I checked the oil this morning and it was black and it freaked me out a little. :lol:

I'll check out both those pages, too!
 
It'll be black as soon as your start the truck after an oil change. :rolleyes: However, if you take a drop of new oil on your finger, you can see the soot kind of separate from the "clean" oil.

I usually change the fuel filter every other oil change, but I might skip two every once in a while. Depends on how long it's been (time wise) since the last oil change. It may sound over kill, but clean diesel fuel makes for a happy truck. I'd rather spend money on fuel filters than aggravation or more money on fixing something or having it quit on me. My biggest thing is getting fuel from the same place every time once I know they have good, clean, fuel.

I'm also really picky about the brand of filter I use. I've got a Cummins so I use Fleetguard filters. On the old 6.2 I used a Purolator, but I'm sure anything other than a Fram would be fine.


There's really not much more to it than that. Change the oil and change the fuel filters. Diesel fuel seems to carry more trash and water than gas does and is much less forgiving about running it through injection pumps and injectors.
 
on the PMD< especially your spare, look INSIDE the connector, you should see a resistor in there

http://www.rockauto.com/catalog/moreinfo.php?pk=2194752&cc=1314023

if it's not, you'll need to either remember to remove the old one from the current PMD when it dies and install, or get get this and install it.

The engine will run all kinds of funky IF it runs at all with out this. ( very commonly missed piece by a DIY'er as they don't know it's there )

a #9 adds more fuel, #5 is somewhat an "economy" chip less fuel.
 
So this morning I started having a problem with the truck. It started fine this morning, but when I went to leave it died. Started it up and it died again.

I had a spare PMD so I replaced it really quickly (it is relocated behind the rear bumper) and it started up and seemed to run great until about 20 minutes later when I got on the highway and got stuck in traffic. It stalled, so I restarted it. STalled again and I restarted it. After that it ran great until another 15 minutes when I was sitting at a stop light by my office and it stalled again. Started right back up and drove it over to the office.

I also noticed that my brake lights now barely work. The third brake light on the cab works fine, but not the taillights. Seems like it is something with the rear body harness. Is there a ground somewhere that might affect the fuel pump and the rear taillights? The taillights wort of work, but they are extremely dim to where you can barely see them.
 
Well, figured out the brake light problem. The wiring in the back is all hacked up and the ground behind the spare tire is wiggly. I screwed around with it a bit and got the taillights working again.

The stalling, I am still perplexed by.
 
Hmmm. Usually the first thing to do is to change the fuel filter. Any blockage can make these things do all kinds of funny stuff. But usually it's not quite that sporadic as you described. But I would try that. You must purge the air out of the system. There's a way to trigger the factory pump on the 6.5 to get fuel to the filter housing but can't remember how right now. To get air out of the lines, crack open a few of the injectors with a 3/4" wrench, IIRC, crank the engine until fuel weeps out of the back of the injectors. Tighten the injector lines, then it should start with some huffing and puffing. The air should clear out shortly.

Maybe too much info for your unknown problem. But try the fuel filter. The OPS on these things can also go bad and tell the computer there ain't enough OP and shut down the engine.
 
Well, I think I found the problem. The PMD was relocated behind the bumper. I replaced it with a spare one and it still had the problem, so I unplugged the extension harness and plugged in the spare one to the factory plug and laid it on top of a bracket in the engine bay. No stall all the way home and I was in stop and go traffic for almost the entire 25 mile drive home.
 
Blaze said:
Well, I think I found the problem. The PMD was relocated behind the bumper. I replaced it with a spare one and it still had the problem, so I unplugged the extension harness and plugged in the spare one to the factory plug and laid it on top of a bracket in the engine bay. No stall all the way home and I was in stop and go traffic for almost the entire 25 mile drive home.
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> remember that part about " none of them are 100% " ?

Don't leave the PMD without a heatsink for long, it will cook itself in pretty short order ( those are resistors you see on the bottom side, they get HOT ) and before you get too excited that the harness extension is the issue, run the engine and wiggle the wiring to the injection pump, wires to optical sensor ( on top of injection pump ) and stepper motor ( on side ) have also been issue in the past, you my have just got lucky with the swap and moved the harnesses enough to make a reasonable connection.....for now.

there are engine/body grounds on the fire wall above the fuel filter, make sure they're clean and tight, the bulkhead connector under the dash thru the firewall to the wiring harness in the engine compartment get loose and dirty, check tightness ( one single bolt in center ) pulling apart and reseating isn't a bad idea either.
 
I just left it without one to get me home. I couldn't stop the truck without it stalling out. I plan to install a new harness before I drive it again.

If things act up again I'll start checking things. Thanks for the stuff to look for, I'll go down the list if things act up again.
 
Something not mentioned is fuel tank issues. I've got a 95 in the shop where the tank lining failed, prevented adequate flow to an already dying lift pump which in turn failed and filled the lines up to the filter with chunks of metal. If you ever notice silver slivers that are non metallic check the tank!
 
mysterync said:
Something not mentioned is fuel tank issues. I've got a 95 in the shop where the tank lining failed, prevented adequate flow to an already dying lift pump which in turn failed and filled the lines up to the filter with chunks of metal. If you ever notice silver slivers that are non metallic check the tank!
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This is reason enough to use a magnet in the fuel filter cup EVERY filter change, those slivers WILL AND DO work there way thru the filter media, and take out the injection pump

This was part of the Extended warranty on the 6.5 injection pumps, GM would only replace the injection pump under warranty ( over $1600 on customer dime ) IF the customer would agree to payment of replacing the lift pump AND dropping, inspecting and relining the fuel tank.

I've replaced several DS-4 injection pumps, only a handful actually had trash in the fuel tank itself, most of it came from failing lift pumps being contaminated by water in the fuel and the lift pump corroding internally.
 
Blkvoodoo said:
This is reason enough to use a magnet in the fuel filter cup EVERY filter change, those slivers WILL AND DO work there way thru the filter media, and take out the injection pump

This was part of the Extended warranty on the 6.5 injection pumps, GM would only replace the injection pump under warranty ( over $1600 on customer dime ) IF the customer would agree to payment of replacing the lift pump AND dropping, inspecting and relining the fuel tank.

I've replaced several DS-4 injection pumps, only a handful actually had trash in the fuel tank itself, most of it came from failing lift pumps being contaminated by water in the fuel and the lift pump corroding internally.
Click to expand...
This one definitely started at the fuel tank. I'll try and get some pictures. This is by far the worst I've ever seen! I pulled approx. A gallon paint can worth of old lining out. The customer is wanting to try and save the ip but I'm doubtful that will happen to be honest. I'm finding what I'd describe as "crumbles" of aluminum and other metals. I'll know more tomorrow. After I install the trucks 6th starter (in a year) a lift pump, fuel tank, strainer and fuel filter lol.
 
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So I think I found my problem. Pretty sure BOTH PMDs that I have here are bad. I put a new harness in yesterday and today I have the same problem. When I install one PMD it stalls repeatedly. When I install the other PMD it stalls occasionally. It stalls with both, but at different rates with each. If it was something else, it would stall at the same rate all the time.

Going to get another PMD and see if that solves the issue.
 
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