Dreaded Lift Pump Leak

[TR4]

Originally Posted by jleamo1

There are two different designs, both called CAPS.
1, ISB and ISC (lower HP engine on the ISC) runs all the time, Bosch VP44 Injection pump. The VP44 while it can draw fuel it doesn't have a fuel pump internally like the big brother in the photo below does.
1, ISC (higher HP), ISL, ISM lift pump is only a primer, Cummins designed Fuel injection pump, not a Bosch pump. looks like this;

jleamo1, thanks for explaining this and clarifying the pumps. I didn't know the VP44 was also called a CAPS.

Bill

[jleamo1]

Originally Posted by TR4

jleamo1, thanks for explaining this and clarifying the pumps. I didn't know the VP44 was also called a CAPS.

Bill

Bill, CAPS tends to follow all of the engines in those years, I'm not sure if its slang or correct. When you speak to someone they identify the Cummins line up as the following;

Mechanical engines
CAPS engines
HPCR engines

It really confused me and I had to ask a bunch of questions to gain a better understanding of what people were talking about. I wouldn't call a VP44 a CAPS system since I do not believe it has accumulators in the pump which is where CAPS comes from, but what do I know

Cummins
Accumulator
Pump
System

Honestly I believe the VP44 gives the actual CAPS pump a bad name (not that its a great design), when you read up most failures are the VP44 when you really dig into it. And with the VP44 in the 5.9 Dodge there are a bunch more of them on the road.