Fuel leaking from bottom of air rail, 2003 Nissan 40 TLDI

[spoolin01]

After 20 years of flawless service, the engine wouldn't start today, and there is gas flowing off the bottom of the air rail box when it cranks. I don't see leaks at any hose connections there, but it's dropping off the bottom from somewhere. Bright sun made it hard to get a clear view of it. Can anyone tell me what I might be facing here? Normally I'd dig into this myself but I've never looked at an air rail, and I'm guessing learning resources are going to be slim. If it's a matter of some new gaskets, that's one thing, but if I need knowledge of other components or specialized testing, I'm inclined to take it down to Marine Outboard in Sausalito.

 

[pvanv]

There are o-rings and stoppers both top and bottom of the rail. Could be one of those.

 

[spoolin01]

There are o-rings and stoppers both top and bottom of the rail. Could be one of those.

Looks most likely to have been the compression seal on the lowest of the 3 air injectors behind the air rail. It looks slightly deformed, and has a bit of white scale or something on it. Could have been from the lower nipple on the air rail end as well, but that seems less likely. Will probably replace most of the externally accessible o-rings around the rail, though I may not remove the various injectors and regulators on the first pass of attempting repair.

Oddly, when I went to begin dismantling the air rail, the motor started and there was not a drop of fuel leaking. It was pouring out the day before. I'm going to start with replacement of a few rubber parts, then see what happens from there. Those seals seem hard to come by online. I'll see about the local service shops.

 

[pvanv]

Any dealer can help you.

 

[spoolin01]

Turns out that compression seal is not available anywhere but eBay. Dealers can't find it, and the one online site that is not OOS, boats.net, says 200+ days to fulfill. For what's essentially an o-ring. Managed to get a couple from eBay, hope they come through. I'm gathering info to order all of the o-rings that go with the air rail, though I may just replace those I've already exposed, on the first go-round.

Here is what it looked like: Leak was off the bottom left half of rail box. Middle pic is backside of air rail box. I didn't take a closeup of the lowest compression seal, but knowing what it looked like, I can barely make out the deformity and white stain in the third pic. I may pull out that lowest air injector to take a look at all of it.