I just installed a custom built fuel pin that a member now makes on here. I was very impressed with the power gains! Anyway, before installing this fuel pin, I have never had injection pump leak issues before. I installed the new fuel pin carefully and it seems to leak diesel fuel out of the rubber vent tube. To be more clear about it.......... I took out the performance fuel pin, mopped up the fuel inside, reinstalled, drove the truck normally for several miles.........no leaks! After checking for leaks under the hood, I drove back home and romped on the throttle hard 2-3 times. The drive home was a little more than 1 mile. When I returned home, I popped the hood and found diesel fuel dripping from the rubber vent tube on the side of the VE pump. I left the pickup idling for about 2 minutes. Only 2 drips came out in the 2 minutes idling.........then the leak stopped!? bottom line: It seems that this leak has occured after putting in a non-stock fuel pin and only leaks when you drive the truck hard. Does the aggressive grind angle of the new fuel pin allow the smaller pin to spring leaks around its O-ring? I would like to know if anyone else is experiencing fuel leaks after installing a different fuel pin.

 

a lot of times the little pin that rides on the fuel cone is somewhat gummed up and when it goes out of where it has been running it causes a leak, are you running the nylon washer?

 

Old Smoky ran into this years ago. There are some pumps that have a shorter side pin, they will leak if the fuel pin allows too much travel. Mike changed his design after running into this on Monty's truck so the pin would work on any truck.

 

Isnt there a sticky somewhere on how to make a longer pin?

 

Yes, I am running the stock nylon washer (unmodified). Everything internally & externally is stock settings/parts, except the 366 spring. The pin is your "M5", that I am running.

 

you could try to limit the travel of the pin more than your nylon washer does.

i havn't seen any of the short small pins like wannadiesel is talking about yet, but yours could be the first.

 

What are the possible sizes for the fuel pins? ? vs. ?

 

One of the schematics I have with p/n's shows two sizes of guide pin listed just like I have them below. The one on the bottom fits the description better from what I have seen. 3mm is less than 1/8"...

Guide Pin, 24,3 MM

Guide Pin, 24,8 MM

 

I would recommend that the regular use of a fuel conditioner such as "Injector Kleen" or "Seafoam" should prevent the buildup of deposits. How ever it may work too well. The gunk my be the only thing preventing leaks.

 

Seals do not last forever. You put the new fuel pin in and the guide pin is going where it has never been before. I'm not surprised at all.

 

my thoughts exactly

 

Is this a common problem with the Denny T pin also?

 

It can be a common problem associated with a high mileage pump or even a low mileage pump with a stock untouched fuel pin or any aftermarket or custom ground fuel pin.

 

It is no particular fuel pin manufacturers issue. If you grind your own the little Guide Pin that rides on the fuel pin eccentric cone will travel further out than it used to. That is the cause of the leak. The o-ring seals do not last forever. Change how something slides thru them and your bound to get a leak.

 

To that I would add, especially a seal that is prone to leak from age, solvent-induced hardening, or a lack of fuel lubricity.