6.2l/6.5l Dead on Road - Now No Start

[thesameguy]

This is my first post here... and I really hope I haven't missed anything posted elsewhere. I am brand-new to diesels much less diesel GM trucks, and I imagine some of my questions are gonna be pretty basic.

Here's the basic rundown:

I'm buying (taking...) a 1984 diesel Suburban from my friend's parents to replace my '87 350 Suburban. Around three or four years ago, they had the oil changed at Jiffy Lube where the oil filter was not securely tightened, and it backed off on the freeway. Some nasty letters and threats later, Jiffy Lube bought them a 6.5l Goodwrench engine and paid for its install. So, it's an '84 with a 6.5l in it. I have no idea what accessories were or were not changed at the time, but it's been running for the last several years.

About a month ago, it died inexplicably on the freeway. It was towed home, and its sat for the last several weeks. This is where I came in.

Last night I charged up the batteries, and added 4 gallons of diesel just to rule out a bad fuel gauge. Adding the fuel moved the needle a little, so I assume the gauge is working, and it is very low on fuel.

I cranked it over for a while, smelled diesel in the engine bay, and upon closer examination found the return hose from the #1 injector was ripped to shreds, dripping diesel on the frame rail. I stopped there, because now I have questions:

1. Is diesel like old CIS injection, where it takes a certain amount of fuel pressure to open the injectors? I saw a reference to injectors "popping" and I assumed that's what's being talked about.
2. Would a ruptured return hose prevent pressure from building at the injector, thus causing no-start?
3. I noticed that the dripping diesel was coming from the pump side of the line, not the injector side. I don't understand why an entire bank of cylinders wouldn't have any return flow...?
4. The glow plug controller is LOUD when it turns on and off. Very audible inside the truck. Are loud thunks normal?
5. Is there any way to test that glow plugs are actually glowing?
6. What's the quickest/easiest replacement for return fuel lines? I saw the bit about using urethane - good idea, but I don't have the time right now to order. If I don't move the truck soon, it gets crushed...

Thanks much for any help... This is a one-owner truck with a ton of money put into the mechanicals. It needs some cosmetics, but its way too nice mechanically to let it go.... 3 year old crate motor! :D

[john8662]

1. Is diesel like old CIS injection, where it takes a certain amount of fuel pressure to open the injectors? I saw a reference to injectors "popping" and I assumed that's what's being talked about.
2. Would a ruptured return hose prevent pressure from building at the injector, thus causing no-start?
3. I noticed that the dripping diesel was coming from the pump side of the line, not the injector side. I don't understand why an entire bank of cylinders wouldn't have any return flow...?
4. The glow plug controller is LOUD when it turns on and off. Very audible inside the truck. Are loud thunks normal?
5. Is there any way to test that glow plugs are actually glowing?
6. What's the quickest/easiest replacement for return fuel lines? I saw the bit about using urethane - good idea, but I don't have the time right now to order. If I don't move the truck soon, it gets crushed...

Welcome to TDP Forums!!!

1. It takes a sizeable amount of pressure to pop the injectors, which is delivered to the injector via the hard metal line, not the soft rubber lines.

2. A ruptured return line would not keep the engine from starting, but is of course a fire hazard, and, well, messy.

3. This sounds as though the injector nut is loose allowing fuel to leak out. That injector won't fire, verify the connectors on the lines are tight.

4. Aww, the relay on the fender is pretty noisy, this is a GREAT sound, because your controller is still commanding glow.

5. Yes, you can test the glowplugs, get a test light, disconnect the glow plug connector, attach test light lead to the positive terminal on the battery, then touch the test light probe on the lead of the plug. If it light's the plug will work, if not, it's an open circuit and burned out!

6. The quickest and easiest way would be to contact one of the supporting venders on this page and order a fuel return line kit and replace them all.

This scenario sounds like the engine was run out of fuel, completly (like I did yesterday in my '82, ugh)...

You may get away with just cranking it over until you get it to fire (assuming you have glowplugs working), but you can also alleviate an airlock situation by cracking open a few or all of the injector supply lines (3/4 nut on injector) and cranking the engine over until you get fuel weeping from them all, then tighten them all back up. The engine should be capable of running then, it may start, then die, etc. but you'll eventually get all the air out of the system.

Maybe the injector return line had been leaking pretty badly, using more fuel than the prev. owner was use to. The ruptured fuel return line can also allow fuel to return to the tank, causing it to be harder to start too!

J

[thesameguy]

That is great information - thanks!

I'll try replacing the fuel return hoses and bleeding the injector lines and see where that gets me. It sounds very much line it was run out of fuel - the kid driving it isn't reknowned for his attention to detail. ;) Is 4g enough in that tank to get things going? I assume since it was dripping up front we're in fact pumping fuel, so I suppose so... Also, how long is "a lot of cranking," and how long can we run the starter? I was oberving standard gas engine protocol of no more than 20-30 second on the starter, then letting it rest, and trying again. Is this good, or can we run the starter longer? I do NOT wanna replace a $200 diesel starter... :D

[Robyn]

The 84 has a little rectangle shaped fuel filter over on the Pass side firewall.
replace the filter and open the bleed screw. Unplug the large red wire from the front of the injector pump. Spin the beast untill you have fuel flowing freely out of the air bleed on the fuel filter. A small hose run into a can is a nice touch and keeps things a lot cleaner. Once you have air free fuel at that point plug the injector power lead back in. Allow the glow plugs to cycle and try starting it. If you get no fire but eventually see white smoke at the tail pipe its a glow plug issue.
keep us posted
Robyn

[thesameguy]

Well, it took almost a month, but I finally was able to return to work on this diesel truck...

I picked up a set of replacement return hoses from NAPA - they are definitely not OEM quality, but I figured they'd work for now. Got another 5 gallons of diesel from a local station, and a new fuel filter.

Put it all in, bled the system at the filter and then at the injectors, and the beastie fired right up. We let it idle for a few minutes, changed the engine oil & filter, topped off fluids, then started the 30 mile drive back to my place.

Somewhere along the line the alternator belt snapped, but it made it to its new home without incident, running great.

Awesome! The truck is an '84 3/4 ton 4WD w/ a 6.5l transplant and 300,000+ miles. My plan is to keep it and sell off my '87 1/2 ton 4WD w/ a 350 ... it's been a good truck, but it has an unknown history, and the diesel has a 5 year old crate motor with I think about 20k on it and since I got the truck from the original owner I have some idea of its service history... No smog testing is also a major selling point.

Thanks for the help - I'm sure I'll be back once I find all the stuff the PO *didn't* attend to... :)

Actually, I do have one question - what the heck is the filler neck right next to the fuel distributor for?

Oh, and I used Shell Rotella 15W-40 for the oil change... hope that was a decent choice.

[DmaxMaverick]

......Actually, I do have one question - what the heck is the filler neck right next to the fuel distributor for?

Oh, and I used Shell Rotella 15W-40 for the oil change... hope that was a decent choice.

The canister toward the driver's side with the cap on it? That's the power steering reservoir. Follow the hose down to the pump.

If you mean the filler toward the front, that would be the crankcase filler. If that's your question, where did you put the Rotella?

Rotella 15-40 is good dino oil. As good as Delo.

[thesameguy]

The canister toward the driver's side with the cap on it? That's the power steering reservoir. Follow the hose down to the pump.

If you mean the filler toward the front, that would be the crankcase filler. If that's your question, where did you put the Rotella?

Ahh... crankcase filler. Makes sense.

I didn't actually do the oil change, I took it to JL. My friend and I were both beat and tired, so we outsourced the oil change... :)

I had seen the oil cap on the valve cover and figured that was it. Didn't realize there was a separate crankcase filler, although that's exactly what it looks like.

[DmaxMaverick]

Ahh... crankcase filler. Makes sense.

I didn't actually do the oil change, I took it to JL. My friend and I were both beat and tired, so we outsourced the oil change... :)

I had seen the oil cap on the valve cover and figured that was it. Didn't realize there was a separate crankcase filler, although that's exactly what it looks like.

Oil cap on the valve cover?? Shouldn't have one. If you are referring to the hose coming out of the passenger side cover, that goes to the CDR (Crankcase Depression Regulator, or PCV to a gasser). There should be NO filler cap on the valve cover. Could you post a pic of it?

[thesameguy]

Sure... will do later tonight... I suppose I could have imagine it, but I don't think I did... :)

[thesameguy]

Okay, so it wasn't later tonight... Anyway:

http://www.cal.net/~jvanabra/burbanoil.jpg

[DmaxMaverick]

Hmmmmm.....

There should be a CDR hose in that hole. What does the cap say? Can't read it, but looks like a cap from a gasser. I've been wrong before, but this one would surprise me.

[thesameguy]

What's a CDR?

It would not surprise me to find something missing from the engine. It's an '84 with a 6.5l transplant, and I don't have full faith that the guy who did the swap knew what he was doing... From the looks of things, he got a Goodwrench long block and bolted everything from the 6.2l onto it.

[DmaxMaverick]

CDR=Crankcase Depression Regulator. It's a Diesel version of a PCV. From the looks of it, the original 6.2 CDR was retained, and the 6.5 valve cover was plugged with an oil cap. The 6.5 has the CDR attached to the valve cover, where your cap is, and a hose runs from it to the intake pipe. The 6.2 has a hose running from the tube on the side of the oil filler (the correct one at the front of the engine), to the CDR mounted above the alternator, and a hose from it to the intake manifold. Just make sure the CDR is in either configuration, and it'll be OK. The only thing you need to know is which you have, so you'll know which to replace with. Currently, if it is there, you have the original 6.2 CDR. If you don't have either, get one on there, or you will have issues with oil consumption, or leakage, depending on what was done in place of it.

[arveetek]

You can see from the pic in this thread (http://www.thedieselpageforums.com/tdpforum/showthread.php?t=24550) that he has the stock 6.2L CDR sitting above the alternator, so he's in good shape.

Casey

[DmaxMaverick]

You can see from the pic in this thread (http://www.thedieselpageforums.com/tdpforum/showthread.php?t=24550) that he has the stock 6.2L CDR sitting above the alternator, so he's in good shape.

Casey

Yeah. I caught that once I made the connection it was "thesameguy":D

[thesameguy]

Glad to know that everything is more or less as it should be... :)