My afc valve on my m919 ntc400 cummins is not working. I think the bellows has a hole. I ended up hooking up regulated air to it and could make decent power but now my ip is leaking fuel. It looks like I will have to pull the pump and have a shop work on it. I found a NIB pump from someone on here and am wondering if I could just put it on and it would work or does it have to be tuned first? Thanks, Ross