Failed 91 Jetta 1.6 injector pump

[shnidilydop]

I'm trying to aquire as much info as possible on this part. Why the seals leak? How to fix or rebuild and will the injector seals just go to pot again?

[82vdub]

Welcome to the forum. A few years ago when diesel fuel was changed to the 15 parts per million (PPM) sulpher content fuel, this causes the injector pump (IP) seals to shrink, causing leaks. It's an unfortunate cause from the changes mandated in the fuels that we use. You can reseal the pump yourself. It's been covered several times in the forum.

If your injectors are leaking, you need to look to determine where at the injector it's leaking. It can leak from the hard injector line fitting at the top, at the midpoint of the injector, at the fuel barbs for the return lines, or at the base of the injector. I'd default to the fuel barbs for the return lines as leaks there are fairly common.

[1984george]

I have the same engine in my '84 Rabbit. When I got it over the summer, the Injection Pump started leaking because I was filling it up with Ultra Low Sulfur Diesel Fuel (as the person above me talks about). I didn't realize it's all they sell now and that you need to add a Diesel additive to help lubricate the pump. Anyway, my pump leaked like crazy and I got it off and had it resealed for about $80 bucks from a local Diesel Specialist. I've driven 3,000 miles since the reseal and no leaks whatsoever....and I run Diesel and Waste Vegetable Oil in it. Don't run vegetable oil without a conversion kit though. You'll definitely run into problems. I'm new to a lot of the procedures also, but I'm starting to get it. Good luck with your pump. Once the seals are redone, you're golden. Maybe try buying a manual? I have a Haynes Manual that was only ten bucks. It's not as in depth as the Bentley manual, but it's all I have, and it's helped me do a few basic repairs. These forums are a great resource also. Try the search.