Restart procedure post Overhaul. Won't crank.

[aw113sgte]

Still no K26 signal but the trans at 6 gallons is not above the hot-low line yet.

on another front, how many pumps does it take to prime a dry fuel system? I could not find a TM procedure on it. I pulled the black plug on the right side of the primer pump and gave it 100 pumps but still nothing coming out.

I replaced my suction line and it wasn't anywhere near that. Something like 20 pumps.

 

[MatthewWBailey]

I replaced my suction line and it wasn't anywhere near that. Something like 20 pumps.

I've never had to use it before so it may be having the issue described in @Ronmar 's video. I looked high and low in the TM on how to use it. I pumped it with the plug out, and the plug in, got no resistance on the button. There's probably a dead mouse in the bypass valve with my track record.

 

[GeneralDisorder]

Changing the fuel filters it typically doesn't take more than 20-30 pumps. Might have to do it a second time if it doesn't stay running. They prime pretty quickly in my experience.

 

[Ronmar]

I've never had to use it before so it may be having the issue described in @Ronmar 's video. I looked high and low in the TM on how to use it. I pumped it with the plug out, and the plug in, got no resistance on the button. There's probably a dead mouse in the bypass valve with my track record.

Did you look at the run out of fuel video I did right before the primer C&I? That shows how you use it, and how it is supposed to work…

 

[Ronmar]

Changing the fuel filters it typically doesn't take more than 20-30 pumps. Might have to do it a second time if it doesn't stay running. They prime pretty quickly in my experience.

If you pre-fill the filters, it doesn’t take much to re-prime. It would take quite a few to fill dry filters…

 

[Ronmar]

Both of those were not tripped. I don't have any codes on the WTEC and it says N on the display but the dash says check trans. I have 7.5 gallons in there now and the dipstick is at the hot-high mark. I'm going to go on a wire hunt to see if something is cut or shorted. What else could it be.

also check the K26 path to ground.

 

[MatthewWBailey]

Did you look at the run out of fuel video I did right before the primer C&I? That shows how you use it, and how it is supposed to work…

So that's pretty simple. Why do the instructions say "open vent"?

 

[GeneralDisorder]

So that's pretty simple. Why do the instructions say "open vent"?

You open the vent to expel water from the separator. That is supposed to be done weekly IIRC. For priming you don't need to open the vent.

Ron is using a filter without the separator it would appear. Our trucks (3126/C7 anyway) have two "filter" heads but the one with the primer has the water separator cup with heating element for capturing and draining water from the fuel. You can't prime the injection pump with the separator vent open - it will just pump fuel out of the water separator hose.

 

[Ronmar]

So that's pretty simple. Why do the instructions say "open vent"?

What General said, they should have used the word drain. You open the drain and use the pump to pump out the water/fuel sample from the bottom of the filter bowl. That is actually one way to confirm if your bypass flapper is sealing. If you open the bottom drain, nothing should happen except a little fuel may dribble out. If it sucks in air and you hear it bubbling up into the filter housing, that is the bypass leaking and the fuel in the fuel line flowing back to the tank creating suction to suck air up into the filter…

That Baldwin filter has the separator, it just doesn’t have the separate bowl Or a heater. Its bowl with a drain valve on the bottom is part of the one piece metal housing . Been using them for decades on gensets, good filters…

 

[MatthewWBailey]

What General said, they should have used the word drain. You open the drain and use the pump to pump out the water/fuel sample from the bottom of the filter bowl. That is actually one way to confirm if your bypass flapper is sealing. If you open the bottom drain, nothing should happen except a little fuel may dribble out. If it sucks in air and you hear it bubbling up into the filter housing, that is the bypass leaking and the fuel in the fuel line flowing back to the tank creating suction to suck air up into the filter…

That Baldwin filter has the separator, it just doesn’t have the separate bowl Or a heater. Its bowl with a drain valve on the bottom is part of the one piece metal housing . Been using them for decades on gensets, good filters…

I'll repeat the procedure in your video today starting with the feed line port suction test. I have a new separator filter I need to install anyway. Clearly it's not pulling vacuum.

 

[MatthewWBailey]

These are the instructions on the pump... hence why I was searching for a "vent"

 

[Ronmar]

These are the instructions on the pump... hence why I was searching for a "vent"
View attachment 928839View attachment 928840

The vent they are probably referring to is over on the second fuel filter boss, large hex plug up on top. on a non return system like on my tractor you would need a vent to purge air. On our looped/return system, they are designed to self purge, so it is just as easy to simply pump any air thru the gallery and back thru the fuel return line to the tank...

 

[MatthewWBailey]

Check my YT channel username Rronmar. Did a vid on the typical primer issue and resolution. Not sure which port you pulled on the primer assembly, but that may keep it from working... 16-18 pumps to lift fuel from tank to primer with an empty line, ~20 more)with full filters) to feel pressure/resistance build on the primer from the pressure regulator once the head gallery is full of fuel.

Your video was spot on. Thanks yet again! There was no vacuum on the inlet port when pushing the button. So I pulled it all off there and found 2 big pieces of RTV stuck in the bypass valve seat. IDK where it came from but it's definitely the consistency of rtv. Must be in the tank? Luckily no mouse in there but at first it looked like a mouse tail. Now it holds the button in if you block the port with a finger. Pretty awesome!

20 pumps and it got stiff on the button and you can hear fluid flowing

 

[GeneralDisorder]

Could be bits of deteriorated old fuel lines maybe? From the inner lining? Good thing you replaced them. I haven't run across anything that looked like that in the fuel system on these trucks. Maybe someone used some gasket maker on the fuel filter gasket?

 

[Ronmar]

Or crap in the fuel supply system pumped into the tank…

 

[MatthewWBailey]

Could be bits of deteriorated old fuel lines maybe? From the inner lining? Good thing you replaced them. I haven't run across anything that looked like that in the fuel system on these trucks. Maybe someone used some gasket maker on the fuel filter gasket?

It's rtv for sure. Feels like it when I pull it apart

 

[MatthewWBailey]

Well K26 is driven directly by the transmission. Do you have both transmission inputs, Battery and IGN? Allison controls some outputs by providing a ground, and others by providing a voltage. The voltage it uses for output is the battery input. Thats why the Vehicle interface Module on the A0 has 12V relays in it(NS and PTO) as the battery input to the trans is 12V(thats the A0 vampire load)... They kept this config into the WTEC 3 where k26 first appears as the neutral Start Relay, but using 24V for both batt and IGN input to the transmission... CB43 provides the trans battery input, CB79 the trans ignition input.

K26 ground is good all the way back to the alt ground. I tested the relay and it's good. I'm a little confused by the schematics bc they show 24v going to the coils but these relays are all 12v coil. Unless, are they halving by using theses R11 and R26 inline resistors? Those are 82ohms. I'll pull the trans connector next to see if it's actually getting power.

 

[Ronmar]

Thats exactly what they did. The A0 specced 4 different type relays, 12-24, 4 or 5 pin. Using the resistors on the 24v control circuits they can spec one type relay 12v 5 pin…

 

[MatthewWBailey]

Thats exactly what they did. The A0 specced 4 different type relays, 12-24, 4 or 5 pin. Using the resistors on the 24v control circuits they can spec one type relay 12v 5 pin…

I have a complete spare PDP for an A1 that I bought from Austin on eBay, so I was double checking voltages when I thought the relay may be bad. Then it dawned on me when I saw those 82 ohm resistors. Just a matter of time now before I find the missing signal.

 

[MatthewWBailey]

also check the K26 path to ground.

Success. It wasn't K26 ground, it was the K11 ground path bc the oil psi switch connector was not fully plugged. That 2 wire plug is hard to confirm, it was together but not aligned. Plus, the LD26 LED isnt working on the PDP, so I was chasing K26 for no reason. I was swapping a spare relay in there and it was clicking on as I put it back in. I'm like WHAT! I tested wire 123 and I was getting a neutral signal all along! Testing across the K11 relay 85 port showed floating voltage, not ground. Only S27 can break that circuit. I fiddled with the S27 plug and got it to click together. Hit the starter and it fired right up in 3-ish revs, oh baby! I turned it off asap bc I'm only at 7gals of coolant so far on the refill and only 6 on the trans.
ITS ALIVE!