starting 84 GMC diesel after sitting for 7 years?

[kidatheart]

I have purchased a '84 GMC with a 6.2 in it. It has been sitting for about 7 years. The PO said he drove it to where it was sitting. He said it was getting hard to start because the glow plugs weren't working properly. He had other trucks and just never drove this one again. I am very familiar with getting an old gas truck started after many years, but not so much on the diesel. Do I need to drop the tank and clean it out, or pump some out and if it looks good, give it a shot? What else should I do? I don't want to create more work for myself! Any advice will be greatly appreciated. Thanks.

[TKCR]

I found this, just looking around. This pertains to diesel fuel:
PRI-D & G stabilizes stored fuels. PRI-D & G can keep diesel fuel, kerosene and gasoline fresh in storage. PRI-D & G can actually restore old fuels to refinery specifications.
I would put the PRI-D & G in the tank along with 5 gallons of fresh fuel. I had the same issue with gas, in my truck, it sat for awhile and I was afraid the fuel was stale. Since mine was gas, I added a can of Seafoam, along with 5 gallons of fresh gas. She started right up. She smoked a little, but I drove it around to run some of the gas out. I then topped the tank off again, with another can of Seafoam.

[Ralph l]

Don't know if you got the truck started.
First open the bleeder screw on the filter housing on the fire wall right side and have someone turn the engine over , checking for fuel . If there is no fuel check the rubber line off the fuel pump on the right lower side f the engine to make sure it is has not cracks and sucking air .
Check fuel injection pump that the power wire is connected.

You should not have to remove the fuel tank unless you know there was something other than diesel put in it .


You can test all the glow plugs with a test light to see if they work . ground one end of the test light to the battery and pull the wire lead off the glow plug and touch the other end of your test light to the power end of the glow plug ,if it lights up its good . you can jumper the glow plug relay but only for no longer than 15 seconds at a time . You will burn them out if held for longer . fuel does not go bad as in a gas engine , so if there is fuel and it turns over it should fire .
Also check oil level in engine first .
I have be driving a 1984 gm diesel since new and do all my own mech work on the truck . If you need more information feel free to pm me i'm here to help.
Ralph

[kipps]

if it were mine, I'd not be concerned about the fuel quality. Diesels can sit for a decade and still pop right off without problems. I wouldn't even change the fuel filter. It's probably holding prime, so no point in losing that by disturbing the filter. Just hook up the jumper cables and give it a whirl.

[special-K]

I would cvertainly dump all fuel and replace with fresh mixed with a healthy dose of fuel conditioner. I am a big fan of Howe's. That old fuel has been having growth going on for years. You do not want any of that passing through your injector pump and there is no additive that can make that stuff go away. I've see 7 month old fuel kill an injector pump.

[44th Miss Inf]

I picked one up a while back that had been sitting at least 5 years without being cranked. Put two batteries in it, and after the glow plugs cycled, she cranked like it had been parked there the day before.

Give it a whirl, worth a try

[kidatheart]

Thanks for all the great information and tips!! I knew this would be the place to find out what to do. I haven't got the truck picked up yet, but as you all well know, once and old truck is on your mind, it's on your mind all of the time! thanks again.

[lowrollin70gmc]

I went through the exact same thing, my 84 6.2 was sitting for about 8 years in the woods behind my grandpa’s house. I’ve been driving it for 3 years and it runs great.

I brought 2 fresh batteries, a fresh fuel filter, and 5 gallons of fresh diesel.

I checked that there was oil in it, then installed the batteries, filter, and fuel. Then cranked it with the fuel filter bleeder open to bleed the air out. Closed the bleeder and she fired right up. These old girls just want to run.

I then drove to the fuel station and topped off both tanks with fresh diesel and started driving the truck (ok, I also swapped out the brake fluid, inspected the brakes, changed the oil, and put new tires on it for safety). I also ran each tank down as far as I’m comfortable with and refilled with fresh diesel.

Edit: Also, half my glow plugs don’t work as mice had chewed the wiring, but it still fires up great.

[kidatheart]

Thanks! You all are giving me hope. I hope my story has a happy ending also....

[44th Miss Inf]

I would update the 84 glow plug controller to the 85-93 one which is more reliable. Very simple to do, and if the glow plugs need changed, go with 60G ac delcos. I can tell you how to add a resistor to the 85 up controller to extend glow time for the 60Gs.

[100%Chevy]

If yours' has a block heater,plug it in a few hours before trying to start it.
The block heater makes it a lot easier to start a diesel!
Mike.

[100%Chevy]

Originally Posted by 44th Miss Inf

I would update the 84 glow plug controller to the 85-93 one which is more reliable. Very simple to do, and if the glow plugs need changed, go with 60G ac delcos. I can tell you how to add a resistor to the 85 up controller to extend glow time for the 60Gs.

I just noticed you're from Liberty,Ms.!
A few years ago,my company built the new jail there.
I did the wiring on it.
Dr. Tishners home was next door.
Jerry Clowers home town too!
Mike.

[kidatheart]

The more replies I get, with tips and good instructions, the more anxious I am to get the truck home. It is about 4 1/2 hours each way to pick it up, so I have to work around my job schedule and the weather. Hope I get it home in the next couple of weeks.

[kidatheart]

Originally Posted by 100%Chevy

If yours' has a block heater,plug it in a few hours before trying to start it.
The block heater makes it a lot easier to start a diesel!
Mike.

That's a good idea. Another one of the little things that will help. thanks.

[Ralph l]

Hi Kidatheart, do check the rubber fuel line from the mech fuel pump they do rough after time and my cause a problem . Hope to see some pic when you bring it home. Also as the post suggested earlier to replace the glow plug controller to the 85 and new as it will work a lot better .

[kidatheart]

I will definitely keep that I mind. I will probably try to drive it for a short time to see how much time and money it is worth dumping into it. Thank you.

[kidatheart]

Originally Posted by Ralph l

Hi Kidatheart, do check the rubber fuel line from the mech fuel pump they do rough after time and my cause a problem . Hope to see some pic when you bring it home.

I thought I would look over the rubber parts and wires before trying to start it-the years and mice could have taken a toll-hope not. The truck is an old farm truck and is kinda rough, but I like to tinker, and I enjoy the challenge.

[Ralph l]

The old style mechanical injection pump will run on just about anything that burns. I have run trany fluid to used engine oil mixed with diesel and it runs waste veggy oil is great to run in these old trucks also.

[kidatheart]

I am planning on picking up the truck Saturday, so there are lots of things going through my head! Another question I have is do these 84's have any kind of a water separator for the fuel-something with a drain on it?

Thanks for any help and info. Doug

[Ralph l]

Yes on the fuel filter on the fire wall there is a water drain which will drain water sitting in the bottom of the filter .
Only open this for a second or two ,is all that is required.

[kidatheart]

Originally Posted by Ralph l

Yes on the fuel filter on the fire wall there is a water drain which will drain water sitting in the bottom of the filter .
Only open this for a second or two ,is all that is required.

Thank you! I will do that.

[kidatheart]

Well, I got the truck home. I looked at the fuel tank switch tank and it was on the right side, so I guessed they might have used that tank last. I took the cap off and it let pressure out, so I figured the system was still air tight. It smelled like diesel. I put 2 batteries out of other trucks in it and it cranked. I rolled the dice, and decided to try to start it. The fuel gauge said it had about an eighth of a tank of fuel. I dumped a good dose of Howse in it, and five gallons of fresh fuel. I knew the glow plugs didn't work. I cranked it short time to get everything lubed up. Then I shot some wd40 in it, and not much changed. So I gave it a short blast of ether, and it fired right up and purred!! Sounded so good! I checked all of the fluids, and took it for a 5 mile crop tour. Amazing after nearly 8 years. It's almost a barn find, except that the guy who parked in the barn never lost it....It's rough, but it's mine....and paid for. Thanks for all of the advice.

[44th Miss Inf]

Good deal.

Give me a bit I'll post how to update to the glow plug controller to the 85-93 model

[Palf70Step]

Glad to hear you got it. You'll have to post some pictures of the ole girl.

[82Diesel]

I'm having a problem with mine 1982 C20 6.2 diesel 79k original. Turn the key & only lights come on, motors not stuck... but won't turn over took off starter tested it and it works.

I was told the relay or fuse thing on the firewall could be it. Any suggestions?