Where do I start?

[DickWells]

Got the old Burb buttoned up, yesterday. New PS pump and harmonic balancer &pully. Eight- mile test drive showed no more PS noise and the rattle from the bad pully was noticeable by its absence. There was much white smoke for more than a mile, which proved to be caused by no power to the cold start advance. Fixed that this morning.

So, we started a grocery run to Show Low, this afternoon. Got 12 miles out and had a shutdown. A few misfires and then, shut off, like it ran out of fuel. Had gotten to the side of the road, hazards on.
* This is a 4911 mechanical pump. The cold start is manual, as well, Toggle switch on the dash. Glow plugs controlled by a button, to a HD starter relay under the hood. All works fine.

Anyway, I'd had it shut down the same way, couple of months ago, right here in the yard. Wouldn't restart, ending with changing the fuel filter, which looked 50 years old. The lift pump was working well, but it still wouldn't re-start. Couple days later; fired up, instantly, which is usually the case.

Back to today, 14 miles away, since we had heavy traffic on rt 60 and had to search for a turn-around. Engine started 3 different times, ending with us back at about 12 miles from home, in a dirt parking area, where it quit again and - - - no start. First thing i did was, leave the switch on, pop the hood and crawl up on the fan shroud and Crack the filter bleed. Pumps like crazy. Called our son, Lance and he headed our way with his DM Dually. I had repeatedly tried to start, with no luck. Batteries are strong and it whips over real fast.
Lance arrived and we hooked up with a long strap. It had been less than 5 min since I'd tried to start it, but, decided to try again, just in case. The usual quick ayuh, and it's running! Lance yanked the strap off the hook and then, I remembered the transfer case was in neutral. Gears weren't meshing,so, I shut it off and engaged 2H, fired it right back up and drove home.

Okay. What I don't understand is, if it's not a failing shut-off solenoid, how come it fires up without one misfire? Any time I've ever dealt with a diesel that shut down from loss of fuel, I've had some very noticeable misfires as the injectors came back on line. Heck, yesterday morning, with no CS advance, it fired up instantly, but it certainly wasn't firing on all 8. More like all 4 or 5. Each time it shut down today, it ran flawlessly, until it shut down, again.

My plan, FWIW, is to start at the shut-off solenoid, unless the experts on the Page check in here with something that hasn't crossed my mind, yet. That old rig is such a delight to drive that I can't think about giving up on it, even though it's been down, more than it's been up, for almost a year. That diesel torque is dang near addictive and nothing handles like a 2500 Suburban.

[DmaxMaverick]

Ignition switch.
Oil Pressure Switch (OPS --it should be relayed, so add the relay to the list. If not, relay it. Or add a Kennedy fuel lift pump control for a gazillion dollars more, because it just works).
In no particular order.
Or something else.

[Robyn]

Like Maverick said IGNITION SWITCH
When you get a no start ...Grab your volt meter and check the voltage at the large red wire that connects to the injection pump.

The mechanical pump is crazy simple......With fuel delivered at the bleeder it points to the fuel shutoff either failing or the 12V supply is the problem.

You should be able to hear the injection pump go click when the key is turn to ON

As Mav said....Ignition switch may well be worn out.

As a work around.....A jumper wire from the battery to the power terminal on the injection pump.......

[DickWells]

Thank you! The OPS is already relayed. One of the 3 big relays that I have on the firewall. Glow plugs, OPS an I've forgotten what the 3rd one serves. Exhaust brake, which no longer there. Regardless, the problem being intermittent won't make it easy. With my home-made t-cable bracket being in the way, my oversized paws, etc., I'll probably remove the air plenum (or whatever it's called) piggy-back a new wire to one of my spare (16) switched fuse terminals and install yet another toggle on the dash, to be ready for the next failure. All depends on IF, I can make it fail with a VOM hooked up solid at the fuel shut-off.
Have either of you ever heard of the shut-off, itself failing? Once accessed, I can easily exercise it, to check it out.
Anyhow, thank you for your patience, while I sit here thinking in black and white. What goes through my feeble brain, that isn't backed up by a hand-written note, is soon irretrievable.

[DmaxMaverick]

I've heard of (suspected) failed ESS (Engine Stop Solenoid), but have never seen one fail in the wild that wasn't physically damaged (one DS4). I've replaced a couple suspected failed ESS (they weren't). Not saying they can't or won't fail, just never witnessed one. They are a coil with a specific resistance range (don't recall it), and can be read with a VOM. I would start with that, before moving onto more invasive actions.

[Robyn]

O have had the DS4 ESS leak fuel out the wire grommet
I had the solenoid on an 86 Burb 6.2 fail to energize ......Turn the key on and smack the IP with A STICK and it would work.

[JohnC]

Any time I've ever dealt with a diesel that shut down from loss of fuel, I've had some very noticeable misfires as the injectors came back on line.

Dick:
Every time you shut the key off is shuts down from "loss of fuel". Our '93 never had misfiring after shutting it down then restarting it. If your shutoff solenoid is loosing power or otherwise closing when it shouldn't, once it opens the engine should run fine, as far as I can tell. It's the same as when air gets into the system.

(Full on mud season up here).

[DickWells]

Hi, John C. I guess what I was making a comparison to, in my statement, is the difference, say, between pulling the shut-down lever, or rod, like on our Kubota, and having a fuel stoppage at a clogged filter, etc. I was aware that fuel has to be "right there" and ready, if the shut-down mechanism is functioning.

Anyway. For all who might tune in, I thought that I had the problem solved this morning, when I took off the intercooler/intake manifold adapter and found the female connector on the shut-off spade terminal was loose as the proverbial goose. Scads of black arcing evidence. BTW, the engine started instantly, as usual, with very little white smoke, since the CS advance has a new switched source and freshened wiring. Shut it down, wanting it cool to work on. Saw the sloppy connection, reached in and turned the switch on and checked with an ohm meter. Twelve volts present. Just for curiosity sake, I took a test cable, with clips at both ends and tested the solenoid from the positive bat terminal and it clicked noisily. So, I worked the connection apart, cleaned up the surfaces, dribbled some Drislide on it squeezed the female connector down for a hard fit and thought the World was in fine shape. Took some more readings with the switch on, and, still confident, got in, turned the switch on, the CS advance on, glowed it for 15 seconds and - - - no fire! Put my jumpers on , direct to the +terminal. No fire.
Well! No voltage to the solenoid, but, with my jumper getting 12 V, there, and still no fire, what am I to think?

This is where I started my second migraine of the day. I had awakened at quarter of six with the jagged, lightning-like light in upper-left. Got up, dosed myself and went back to sleep for an hour, or so. FF to the afternoon and the resulting no fire, with a new set of jagged lights, upper-left, and I get me back to the leather loveseat/recliner and two-each of faithful Tyl/Ibu, eyes closed for 25-30 minutes, and it's off to ShowLow in the Miata and late lunch at Wendy's. I've often suspected that stress is a great trigger for migraines, but this thing with the Burb isn't that big of a deal.

Anyhow, we're looking at several possibilities. Oh! Here's a bit of info that I haven't mentioned. The wiring to the shut-off is a #14, maybe 16 and it comes out of a 4, or 6 pin connector that was part of the factory wiring when it was electronic. I haven't traced it, nor have I looked at the wiring diagrams. When I do, I'll make sure of where it goes from ig-switch to the pump. Another thing that I need to check is, what will happen with my jumper and 12V, when I disconnect the wire from the switch? Another question. If the solenoid is bad , is there any way of proving it, other than taking the top of the pump apart? Proving the wire, and/or the switch, is fairly simple. Proving that the shut-off is junk, would be simple if it didn't sound so "normal". Regardless, I'm gonna be getting a lot more Old Man's purple bruises on my forearms and hands, me thinks.

[Robyn]

Dick

Connect a jumper wire (Decent size ) Directly from the battery to the solenoid on the IP
See if the beast will start ....

If the solenoid is clicking and it does not run....The issue may well be that the solenoid and or linkage in the IP has gone south......

[JohnC]

I guess what I was making a comparison to, in my statement, is the difference, say, between pulling the shut-down lever, or rod, like on our Kubota, and having a fuel stoppage at a clogged filter, etc.

I don't think there is a difference, unless there's also an air leak. If you don't allow any air into the system then the worst case is you will draw a vacuum, in which case you could have some bubbles of fuel vapor in the lines. There, I've contradicted myself.

[DmaxMaverick]

I don't think there is a difference, unless there's also an air leak. If you don't allow any air into the system then the worst case is you will draw a vacuum, in which case you could have some bubbles of fuel vapor in the lines. There, I've contradicted myself.

Not really. Outgassing can occur in #2 fuel. Higher temps allow it to occur at lesser vacuum. Actually, temperature can be linearly exchanged with vacuum. More vacuum just lowers the boiling point, which is what outgassing is. Enough vacuum can reduce the boiling point to the current fuel temperature. The DB2 transfer pump, and probably more so with the 4911, is quite robust and will itself pull fuel enough to run nearly as well as with a running lift pump. If a supply line were to be blocked, it's possible to outgas the fuel, more so at higher fuel temps.

It happens routinely on my 2001. I can tell it's time to change the OEM filter when I get a cold start stall. I have a first generation Kennedy Mega Filter, and it has an air gap. When the OEM filter becomes more restrictive, the suction increases quite a bit (I have a the Kennedy fuel system gauge to show it above 10" at about that time). At this time, a hot shutdown followed the next day by a cold start sends a slug of air to the high pressure pump, and it loses prime. It will start, run about 5 seconds, then stall. It's easy enough to prime and purge the air, which gives me enough time to change out the filter before it will stall again. The system had no air leaks, and will hold sustained vacuum indefinitely. I say "had no air leaks", because it has one now, at the fuel filter heater seal. Showed up a couple weeks ago. Stalled, then stalled again well before it should have. I have a seal kit and new filter in hand, and it will be dealt with in short order.

[DickWells]

Having a cautiously optimistic evening. Didn't bother trying to start the Burb, this morning. Started by checking my 12V source with ign-sw on. No voltage. Connected a questionable test lead (#16, W cheap clips), to known good switched, fused 12V. Couldn't hear the SO solenoid. Knew I wasn't gonna fool with the little lead from the pre-mechanical days, anyway, so I pulled the bigfem connector and clipped the wire. Got a length of good #14, crimped on a new 1/4" fem insltd flat connector for my aux fuse block, and, not being able to lay hands on a big connector for the spade term on the solenoid, I strpped the wire right back to the base of the original, did the same to my new lead. Put 2 layers of shrink-tube down the wire, twisted them together and soldered and insulated them. Found some shrink tube big enough to protect the big connector, which had been naked for ???. Clipped onto my fuse block, turn on the key, and, with a stiff breeze in the junipers overhead, making a lot of noise, I thought I could hear a click from the pump. Pushed the connector home with foot-long needle nose, got aboard, turned on the cold-start toggle, glowed for about12 seconds and it was running instantly! Before I gave up for the day, I'd started it over a dozen times and drove it about 10 minutes, overall.

Gonna hook onto the little trailer, tomorrow, and make a transfer station run. About 12 miles, each way. Gonna have enough tools on the floor behind me to take the top off and pull the shut-off to get home; worst case. Not a pleasant prospect, but - - -.

Reading your exchang on air leaks, reminds me of how many fewer incidents of priming and purging I've had since going mechanical. Then, there's the lift pump relay. Way back, I used to keep a paper clip under the fuse block cover. Now, I can't remember the right numbers to jump.82&30 It's gone from memory, now. Anyway, the old gal almost startles you, it fires off so quickly. Don't remember that it was that fast, when it was electronic.87&30??? This is gonna bother me all night!

Fingers crossed, for tomorrow. Take care and thanks for your help.

[Robyn]

Sounds like the issue was definitely a bad connection......

[JohnC]

82&30 It's gone from memory, now. 87&30??? This is gonna bother me all night!

30 -> 87

Sleep Well(s)!

[DickWells]

Thanks,John C. I'm not quite brain dead, yet. Well, except for the unknown number of common words that I knew yesterday and can't remember, today. But, I just glanced over by the front door, and confirmed that my keys are, indeed, on the key rack. Oh! I actually forgot to think about that relay, until I saw your message!