Strange Crank No Start Condition

[dherman304]

Sounds like you are not getting any fuel to the IP, even with the run solenoid in shutdown the lift pump should fill the body.
I would look closely at the lift pump, also have you removed the check valves in the fuel system?

interesting thought, I feel very strongly the lift pump is doing its job as it shoots diesel out of the fuel filter. In fact as soon as I loosened the clamp on the hose it started spraying diesel. Also, why didnt it run when I filled the IP with Diesel? BUT I will investigate!

 

[TOBASH]

If you’re getting fuel to the IP and not getting fuel to the injectors, only two things comes to mind.

Bad fuel cutoff.

Bad IP.

I feel your pain.

 

[Mogman]

interesting thought, I feel very strongly the lift pump is doing its job as it shoots diesel out of the fuel filter. In fact as soon as I loosened the clamp on the hose it started spraying diesel. Also, why didnt it run when I filled the IP with Diesel? BUT I will investigate!

The IP does not draw its fuel from the body, the high pressure end get its fuel from the transfer pump at the fuel inlet, If you have sufficient fuel pressure at the actual IP inlet then one possibility is the fuel inlet filter in the IP is plugged.
As I said even with the fuel in shutdown you should get fuel in the body

 

[dherman304]

BINGO !! What did it win? Not another toaster lol.

Sleep or study up on the DB2 metering valve. It's a little fuel control valve down in the bottom center rear (from front of truck) of the reservoir that needs to move freely. Looks like a little wing flipper thingie with linkage. If sticky / sluggish action it MAYBE gummed up.

Since you have the housing cover off, check for play ... flip flop like in the movie. ( I don't endorse statements, just the visual to locate it and action) Pictures worth a thousands words haha. SEE >

Funny statement at end "that what you want to do" LOL

One can refill / top off reservoir, CAREFULLY and proper reassemble cover / wires. Attempt to give it a few tries to start. This may not be the fix or a permanent solution. As I said "a free guess" to get fuel flowing if it is all gummed up.

There's a LOT going on in the DB2 IP and not enough bandwidth here. Save up some $$$ if one need a pump.

Wasn't BINGO a dog? CAMO

armature moves freely and the solenoid requires a lb or so to close then opens back up very easier.

The IP does not draw its fuel from the body, the high pressure end get its fuel from the transfer pump at the fuel inlet, If you have sufficient fuel pressure at the actual IP inlet then one possibility is the fuel inlet filter in the IP is plugged.
As I said even with the fuel in shutdown you should get fuel in the body

As I dive deeper I think if there is an inlet filter on the IP than it must be clogged.

As a side note, I did notice the overflow line from the lift pump was melted shut, I just fixed it with some tubing. I wonder if they over pressure at the IP could cause any damage? ALso explains why fuel squirts all over the place when I crack open the fuel delivery line to the IP.

 

[Mogman]

armature moves freely and the solenoid requires a lb or so to close then opens back up very easier.





As I dive deeper I think if there is an inlet filter on the IP than it must be clogged.

As a side note, I did notice the overflow line from the lift pump was melted shut, I just fixed it with some tubing. I wonder if they over pressure at the IP could cause any damage? ALso explains why fuel squirts all over the place when I crack open the fuel delivery line to the IP.

Have you busted the line at the IP to make sure fuel is getting there and not relying on the fact you have pressure at the drain valve?
It seem unlikely that you would all of a sudden have a plugged filter at the IP, it most likely would have low power first.
How many miles has it been since you changed the firewall mounted filter?
That filter on the input of the IP is not meant to be serviced with the IP in place and is a real PITA to work with on with the IP installed.

 

[dherman304]

Have you busted the line at the IP to make sure fuel is getting there and not relying on the fact you have pressure at the drain valve?
It seem unlikely that you would all of a sudden have a plugged filter at the IP, it most likely would have low power first.
How many miles has it been since you changed the firewall mounted filter?
That filter on the input of the IP is not meant to be serviced with the IP in place and is a real PITA to work with on with the IP installed.

checking the IP inlet was what I had planned to do today but found it impossible with the intake manifold still on. Its well over 100 deg. here in texas so Im waiting for the evening to start on the intake manifold.

filter and screen looked great when I replaced them last year. I dont drive it much since its so hot, maybe 100 miles.

I have surgery tomorrow so I wont be able to work on it much. Once I can, I'll pull the IP and look at the filter.

 

[Dieselmeister]

Before you pull the IP - do you have any bore scope you could use to look into the fuel inlet of the IP to see if it's clear. Also, after all the disassembly work, you most likely have air in the injector lines. I would keep looking into the fuel supply into the IP before pulling it (major project), and purging the injector lines again. If you can, hook up 2-3 feet of clear tubing to the IP inlet, tape it to the window center post, fill it with fuel, crack open all 8 injector lines, then crank the engine and see if the level in the tubing drops. If you need to do an extended crank, you could pull all glow plugs. It will crank much faster and easier with no compression.
The fact that it ran before, and also started before the problem started makes me think its a simple problem we are overlooking. My thought - When you started it after vacation, it started with the residual diesel in the hose, then air got pumped into the IP, and now you are fighting an air lock in the injector lines.

 

[NDT]

All this fuel diagnostics rabbit hole and we still haven’t established if the glow plugs are working.

 

[dherman304]

All this fuel diagnostics rabbit hole and we still haven’t established if the glow plugs are working.

They are pretty new and when the truck goes into wait mode I can see and measure and voltage drop but Its still worth a check of all of them. Im still more worried that nothing is coming out of the injeciton line headed to the injectors.

I wont be able to work on it for a few more days, Drs. orders.

 

[dherman304]

I think I found my problem, After fighting to get the advance screw plug off, I pulled the advance pin and found it had sheared off in the pump. I only found part of the sheared part. Still missing the nub at the end of the pin....



anyone have a trashed IP they could grab the advanve pin put of? Cant find it anywhere on the internet!

 

[Dieselmeister]

HPG shows them in stock.
5740654 / 01-189-2141 5315-01-189-2141 - PIN, CAM ADVANCE | Hummer Parts Guy (HPG)

The question now is, what produced enough force to shear it off? Was it an anomaly, or is that problem still lurking in the pump?

 

[dherman304]

HPG shows them in stock.
5740654 / 01-189-2141 5315-01-189-2141 - PIN, CAM ADVANCE | Hummer Parts Guy (HPG)

The question now is, what produced enough force to shear it off? Was it an anomaly, or is that problem still lurking in the pump?

My concerns exactly.

 

[Mogman]

My concerns exactly.

Can you turn the input shaft? if so does it have some resistance? If you take the top off can you see the fly weights turning in the governor housing?
That IP needs to go to a diesel injection shop, replacing that piece will not likely get the IP going.
EDIT, It does look like something seized in the IP, if that happened then two likely scenarios occur, one is the input shaft in the IP shears off (the best scenario) or two the key in the gear that drives the IP sheared off, this would require dissembling the front of the engine to open up the gear case.

 

[TOBASH]

Best idea is to purchase new IP.

My mechanic suggests marine IP and swap the 8 nipples to accept military style. Upgrading to marine IP and injectors wakes up the engine according to him.

 

[dherman304]

Can you turn the input shaft? if so does it have some resistance? If you take the top off can you see the fly weights turning in the governor housing?
That IP needs to go to a diesel injection shop, replacing that piece will not likely get the IP going.
EDIT, It does look like something seized in the IP, if that happened then two likely scenarios occur, one is the input shaft in the IP shears off (the best scenario) or two the key in the gear that drives the IP sheared off, this would require dissembling the front of the engine to open up the gear case.

any chance you know the rotation of the injection pump? I keep reading conflicting info. At first I saw all are clockwise, then I saw someones was running counterclockwise, but the spare IJ I just bought is clockwise?

 

[Mogman]

any chance you know the rotation of the injection pump? I keep reading conflicting info. At first I saw all are clockwise, then I saw someones was running counterclockwise, but the spare IJ I just bought is clockwise?

The cam is driven by a chain off of the crank, the IP is gear driven off of the cam.
So standing in front of the engine the crank and cam turn clockwise and the IP turns counter clockwise.

 

[dherman304]

Got a new cam advance pin and reinstalled the injection pump then filled with diesel. I tried turning it over with the intake manifold off and an injection line cracked open but nothing is coming out yet. Currently letting the batteries recharge before I give it another shot.

 

[Mogman]

Got a new cam advance pin and reinstalled the injection pump then filled with diesel. I tried turning it over with the intake manifold off and an injection line cracked open but nothing is coming out yet. Currently letting the batteries recharge before I give it another shot.

You are going to have to make sure you are getting fuel to the fuel inlet, that IP does not draw fuel from the governor housing, that is the excess, the last place the fuel goes before being returned to the tank.

 

[dherman304]

You are going to have to make sure you are getting fuel to the fuel inlet, that IP does not draw fuel from the governor housing, that is the excess, the last place the fuel goes before being returned to the tank.

I have a solid flow of diesel leaving the seperator/filter at the flare fitting going into the injection pump. Still nothing at the open injector, is there any chance this has something to do with the cold advance solenoid affecting the injection pump bleed back line to the tank? I disconnected the bleed back line checked the tiny check valve which was ok., tried to start it and nothing came out the bleed line?

 

[Mogman]

While you had the IP out did you confirm that the governor weights were turning? was there resistance to turning the input shaft?
The only reason I can think of that would cause the advance pin to be sheared is because the IP seized, sometimes that shears off the shaft, I would think if that were the case the input shaft would now turn rather easily.
You obviously have more time than money, I would not go through all that work without installing a known good or rebuilt IP.
Do you have the factory port caps for the intake ports? if not be extremely careful not to get any trash in the intake ports.

Even with the fuel in shutdown and or the pistons (they actually are called plungers) stuck as long as the transfer pump is turning/working it should be pushing fuel out of the return port with the fitting (check valve) removed.