VW non-turbo injection pump question

[58custom]

This is a 1982 Rabbit truck with 1.6L diesel.

The PO had installed a small gasoline-type fuel filter in place of the original VW large filter/water trap. Following the filter was a small electric fuel pump (2-4 lbs psi). I didn't like the idea of the small filter and I assumed that it might be a restriction, so I got a stock filter assembly from the junkyard, replaced the element and installed it. After that, the truck became hard to start in the mornings, and would smoke when cold like it was way rich. I thought that the electric fuel pump might be a cause, and the stock fuel system did not use one anyway, so I removed it. That hard starting and smoke went away and the truck ran fine.

So my question is: Is the fact that the truck ran rich with the electric pump feeding the IP indicative of something wrong with my IP?

[Morninglight]

The injectionpump does not need a feedingpump, so if you add one the pressure inside the pump will be higher and problable cause it to inject too much fuel because the starting pressure was higher to start with.

A gasoline fuelfilter is too restrictive to use with diesel.. the previous owner like to solve problems instead of solving the cause I think ;)

[58custom]

The injectionpump does not need a feedingpump, so if you add one the pressure inside the pump will be higher and problable cause it to inject too much fuel because the starting pressure was higher to start with.

This was my assumption, that the added electric pump was presurizing the inlet portion of the IP and causing higher outlet pressures, but I don't have any documentation or exploded views of the pump and am unfamiliar with them. I gotta get hip to these pumps. Do actual factory VW manuals have rebuild info on these? I know the aftermarket repair manuals do not.


A gasoline fuelfilter is too restrictive to use with diesel.. the previous owner like to solve problems instead of solving the cause I think ;)

This confirms my assumption on the filter as well. Obviously, this is my first diesel. As for the PO being a bit short-sighted, you have no idea! Most of my time making repairs to this truck has been spent repairing the POs poor "fixes". Thanks!

[Darth Garry]

I've never heard of a diesel with an electric fuel pump. Take it out and see if it fixes it!

Garry

[mortskeg]

58 custom-
Welcome to the forum!
The bentley manual is great for most all repairs etc, however it tell mostly how to instal and time the injection pump, but not much on its inner-workings. For that I would suggest checking out this online manual provided by DR. Cool-
http://www.fostertruck.com/Files/VW_diesel_77-83.pdf
as it has a good amount of info on diesel theory and I.P. operartion.
hope this helps. :cheers: :cheers: :cheers: :cheers:
http://img.photobucket.com/albums/v400/glen_ekstrom/injpump.jpg
http://img.photobucket.com/albums/v400/glen_ekstrom/yellow.jpg