2001 Dodge Cummins question. What would cause a cracked fuel injector nozzle? It is number 6 and number six Bosh VP 44 port had no pressure. Are the two failures linked?

 

By nozzle, you mean the injector tip that's actually in the cylinder?

If there's no pressure at the #6 VP44 port, then I'd say it's because your injector is leaking off the pressure that's supposed to build up.

What happens on these systems is that the injector is supposed to be sealed closed, and it takes a certain amount of pressure to "pop" it open and cause fuel to flow through the nozzle. If the injector is badly leaking, then this pressure will be bled off.

It's possible that such a failure caused the cracked nozzle-- or even possible that the cracked nozzle is itself the point of leakage.

Nozzles can crack for a number of reasons. Foreign debris in the nozzle may cause a crack (both due to needle pressure, but also the lack of fuel flow to cool the nozzle).

That said, injector failures on this particular year of engine are pretty rare.

An cheap and effective upgrade/repair would be a set of RV injectors. They are genuine Bosch and high quality. They also add a little power and improve mpg. Figure about $270 for a set of six new injectors. If you have a lot of miles on the truck, you'll especially notice the improvement.

Injectors can get "tired" after a lot of miles.

EDIT: I see this is your first post on DTR-- welcome aboard! You'll love it here-- it's a fantastic group of people.

jmo

 

The injecter is cracked, a visable break, where the injecter body is screwed together. The internal lower threaded piece is broken toward the brass or copper colored washer seal. You can catch your finger nail on the break. I have had the VP 44 pump replaced because of a PO306 #6 cylinder misfire code. The old pump had very little fuel pressure when the line was loosened at the #6 injecter. The new pump didn't cure the misfire or code. Removal of the injecter found the crack.
Your mention of low fuel pressure from the VP 44 may have caused heat that cracked the injector may be my answer I was looking for.
Thanks for the welcome on my firse post. Lyle

 

I lost the engine due to my #3 nozzle cracking and breaking clear off...Everyone says its rare for a stock injector to do this, But I keep hearing more and more stories of the same thing!

Rick