My question is about a fuel leak that is coming out of my injector pump. I know what caused it and where it is leaking from, but would like some information about how to fix it. It is leaking from around the fuel pin that rides on the eccentric cone inside the afc housing. The reason that it is leaking is because I had gutted my AFC, including the diafragm, cone, and spring, causing upwards of 30 psi of boost to be applied to the seal around this little pin. I have since replaced the diaphragm to seal the boost from this pin, but left out the spring. My AFC housing has been completely full of fuel ever since and is slowly leaking down the back of the pump and side of the block.

I am wondering what kind of seal this is that would need replaced. Is it something I would need to get from a Cummins distributor, or is it a generic o-ring that I could find in almost any o-ring kit. I have not taken my pump apart but am planning on a 3200 gsk in the near future, so i figured I would get everything lined up ahead of time and replace this all at once.

I think I have heard mention of somebody else talking about making this same mistake in an earlier post (wannadiesel?), but am not sure if i remember right.

thanks in advance for the help

Adam

 

Nope, not my mistake. I think that one happened to Pastor Bob when he shaved the shim too far. Your problem is that the little pin has a boat-tail shape at the end, and by gutting the AFC you allowed the pin to come out too far which allows fuel to leak around the pin. You need to put the fuel pin back in, you can grind it some if you want to keep the extra power, but if the pin is sticking out too far you will still have a leak. As long as the O-ring didn't get pushed out of its groove the pump should reseal once you put the fuel pin back in.

If you grind on the AFC lever when you do the gov. spring, you need to have the AFC functional again anyway. You really don't want ALL the fuel the pump can put out right off idle. You need some boost before you get full fuel.