Cummins 4BT startup help

[Hojack]

Got to point of starting up 4BT. Got fuel to injectors and turning over but not firing. Perhaps we have the fuel lines backwards. Which is sending and which is return?

 

[Prairie Swamp]

Is this a Bosch rotary pump? When you crack the lines at the injectors fuel comes out?

 

[Hojack]

Is this a Bosch rotary pump? When you crack the lines at the injectors fuel comes out?

Fuel is coming out the injectors in spurts.

 

[Hojack]

On the fuel lines which line is sending and return?

 

[61twpw]

If you have fuel squirting at injectors, you have it hooked up correctly. Try tightening the #1 and#3 injectors, then crank again. Should fire up. Can tighten #2 and 4 while running.

 

[Hojack]

Fuel not squirting from 2 or 3

 

[61twpw]

Sounds like you still have air in the system. Seems like it took forever to bleed mine.

 

[Prairie Swamp]

Yeah thats why it's nice to get it running on a couple pots - let the motor do the pumping.

 

[Hojack]

Frustrating
Checked to make sure we were correct on timing
I’ve tried to trace the fuel lines. Which on is the supply and the return?
I’ve got the one closer to rear for the supply and the one towards front return.

 

[Hojack]

We may have traced it to the electric fuel pump. It’s still in but we are not using it.

 

[The Phoenician]

That sucks dude. I remember mine took several tries before turning on. It had to be primed a few times, but mine is an inline pump so it may be different.

 

[Hojack]

I’ve read about problems starting these motors. One thing at a time.

 

[Zjohnsonua]

If you're getting fuel to any of the injectors then you're getting close. Got any info on which injector pump it has? Those engines came with several options depending on it's intended use.

 

[Hojack]

It’s a VE pump. It was removed back in January and we now think it’s off on timing.

 

[Hojack]

Injection Pumps have a key to lock the pump. Apparently we forgot to lock it when we removed it. Hopefully this is the problem.

 

[Zjohnsonua]

Indeed they do, it sets the pump to correct timing for #1 TDC. Lock the pump and set cylinder #1 at TDC. Make sure the pump shaft and gear bore are clean before installing the pump gear. I mean, like the cleanest thing you've ever seen. No residues of any kind should be present otherwise you'll risk slipping the gear after install.

Best of luck with the install. Hopefully it gets you squared away and has that diesel rattling before long.