Pulled out my over flow valve last night, had to grind the head a bit. Pulled the valve apart, spring was in one not broken measured the spring, .325" read on forum should be .500" stretched the spring to .500" reintalled valve. Road test, Wow what a big diffrence. Way more power in lower rpm, and the slight miss at idle is gone. one happy camper!

 

What purpose does this over flow valve have and what kind of "problems" occur when this over flow valve is bad?

Rich.

 

The over flow valve is at the return line port of the pump. It is a relief valve that maintains fuel pressure. The spring can get weak or brake in the check valve. Symtoms would be low power, slight engine miss or hard starting.

 

and white smoke

 

Hmmmm... Now I cant help but to wonder if I just didnt pay out $2104.96 for a new pump when all I needed was this valve.

Oh well, I got a new/better pump out of the deal.

Rich

 

jlipskoc,
Yes, I got a better than stock pump, but I went with what Cummins calls a "175 kit".
Its the same basic pump as the 180 pumps on the mid 90's trucks.
My truck came with the 160 pump stock.
The Cummins kit also included new injectors (bigger, I dont know).
The reason for me taking the truck in was a stubborn miss Ive had since owning the truck.
I did not have any white smoke nor did I notice a loss of low end power, just a "miss" at idle.
The new pump took care of all that and gave me a little more power.

I dont think my problems were because of the Over Flow Valve, but Im not sure.

Expensive? YES! But worth it just to get rid of that aggravating miss I had.

Rich.