I just got my 02 Jetta back from the dealer. It wouldn't start. The problem was a bunch of sludge that had accumulated in the pump. They drained the gas tank, cleaned out the pump, and it is working again. I've been running various mixes of B50-B100 for 40,000 miles without incident.

Anyone else have this happen? Anyone tried to install some kind of filter before the tank pump?

Any response is appreciated.

dt

Do you think the sludge came from the biodiesel (BD) or was it flushed from the tank due to the previous dino diesel? How clean is your BD? I have just started to run BD in my 03 TDI jetta and expect to plug a fuel filter shortly due to the 100k miles of dino diesel. But I have not heard of a filter problem in the tank.

I suspect that adding a filter prior to the fuel pump would simply back up the problem, and you would need to drain and get into the tank to clean the filter.

Sludges can form in your fuel tank. This is due to the type of feed stock, products of oxidation, Bugs and algae or bad batch process (glycerine and Sterol Glucosides).

All VW's have a stainless mesh filter locatted inside the fuel sender unit which is in side the plastic fuel atnk. Its about 200 microns. This can block up with sludge etc

The newer VWs (PDs) have a electric lift pump located inside the fuel sender unit. If the mesh filter gets blocked this can cause the pump to burn out.

Some folk have replaced this fine mesh with a course one and fitted an in line filter prior to the stock filter. These filters have glass bottom so you can see any sludge and deal with it. http://trueasset.org.uk/index.php?page=fuel-filters

Others have replaced the electric lift pump (week design) with a gear pump which can handle the thicker fuels. The VW lift pump is removed and replaced with a short section of pipe. The gear pump is located out side the fuel tank.

Slabs

quote:

Anyone else have this happen? Anyone tried to install some kind of filter before the tank pump?

An '02 TDI will not have a tank pump.
Only used in '04 and later Pump-Duesse TDI's.

In any case a filter will not catch all forms of possible 'sludge'. It will not stop glycerine or algae or bacteria.

Any residual petro based 'sludge' would have been dissolved in the first few tanks of B50+ long ago.

A sample of the bad fuel should be tested for excess glycerin. Thats a common problem with homebrew. It finishes reacting in your tank.