95 12 Valve. Been having a problem with low power but easy starting. So I did the test on the intake to check for leaks in the intercooler boots, etc. Found a small brass fitting with a 90 leaking at the back of the pump and the plastic line that runs from it to the IP is also leaking. I figured this must be the overflow valve, but after re-reading several posts found that it isn't. Well I ordered a OFV this morning, that is fine I am sure mine could use a new one. But what is this fitting that is leaking? It has a small hole where the air is coming from does that mean it is defective? Also I called Cummins today and the plastic tubing doesn't show up on any of their stuff. Does anyone know where I can get one or what it is called. Thanks for the help. I did a search for a picture of the IP but couldn't find this fitting.

 

After almost giving up I somehow stubled onto another site which showed a pic of the fitting in question. It screws into the back of the AFC housing. It appears that the 90 is a Boost Elbow that came with a BD fuel plate that I had installed years ago by a diesel shop. The question now: should air be leaking out of the small hole in the side of this fitting when I am pressuring up the intake system?

 

Does that whole have threads? They make those 90s with a threaded whole and an allen screw in them. You can adjust the allen in or out and meter how quickly the air goes threw, so you can fool the afc, or waste gate. Check and see if its threaded and if it is take it off and go to the hardware store and find an allen that fits.

 

Here is what i mean if you dont understand. You can see the allen screw in the brass elbow.

 

It shouldn't be leaking.
I'm thinking the allan screw has vibrated out.

 

Sorry everyone, I didn't give a good explanation of the leak. It is on the side, just a very small drilled hole. Almost seems like a pressure relief. The allen screw is still in the top of the fitting. I found pics of these fittings installed on turbos but mine is on the back of the pump. Thanks for the help.

 

It is common for them to be installed at the back of the pump. If the fitting is leaking from a hole other than the allen screw, then the fitting is bad. This is an aftermarket part, it is installed to delay the opening of the wastegate. If you need another you can search ebay for "boost elbow" or call up any turbo shop. They are around $20 if I remember correctly.

Hope that helps!

 

Thanks. You guys are great! I will put it back together and order the elbow. I would assume that it is ok to drive since it has probably been leaking for sometime now. Cummins didn't have the plastic line instock $60, but Kenworth made a 1/4" line out of spare parts that should fit.

 

I thought the elbow was supposed to have a hole in it?? Isn't that how it bleeds of the pressure??
The pressure does not bleed out from the allen screw, that is only the adjustment.
This is assuming I understand the problem correctly.

 

Good point. I just PMed one of the BD guys. Makes sense now that you mention it, I'll let you know what I find out.