Vormax System in W123...problem when switching to "main" tank...

[pgellers]

Hi-

I'm brand new to the forum and new to MB and to running WVO, etc. So please forgive me if I say anything foolish, or that doesn't seem right!

A week ago we purchased a 1982 300CD with a two-tank Vormax system and a hot fox tank heater. The system was professionally installed about
5 years ago. We have put about 400 miles on the car and all has worked
just fine until today. Always started and finished on the small
diesel purge tank (after 80C reached). The "main" tank has a mix right now of a little bit of SVO and mostly conventional diesel.

When I switched to the main tank earlier today after 80C was reached,
the car began to sputter, lose power and then stalled. I tried to
restart with no success. I switched back to the purge tank and tried
to restart....nothing. Finally I decided trying to use the primer
button on the injector pump. I primed about 10-12 times and then
restarted the car with no problem. The car ran fine for another 20
miles on the purge tank. Feeling brave, I decided again to try
switching to the main tank. Shortly after flipping the switches the
car again lost power, sputtered and stalled. So I repeated the
priming, restarted, and got it home on the purge tank.

After I got home I tried switching to the main tank at idle and it worked fine for several minutes. When I gave it some throttle though it started to run a lot more rough and stalled after 20 seconds or so. In noticed that the "bulb" (looks like a primer bulb on outboard engine) on the outlet side of the vormax was quite full and firm. Seemed like it wasn't this way when all was working fine.

So, now what? I'm am fairly mechanically inclined but the complication added by the SVO system has me a bit lost! Do I need to change
the fuel water separator? (the gauge is hard to read but looks like it
is pointing on the line between white and green). Is there another
filter for the SVO? I am assuming the main spin on filter is fine
since all runs fine when running on just the purge tank. If I do need to change the separator and / or other filters, what is the air purge process with the two tank system?

Does anyone have diagrams of a similar system?? Any help would be most appreciated! Thanks, Paul

I tried to include a few photos that might help understand how this thing is plumbed.

[pgellers]

Good news (I think). I ran the car to and from work today on dino-diesel in the small (purge) tank. Still no problems. When I got home I switched over to the main tank and return lines and let the car idle for about 7-8 minutes, thinking this could possibly clear out any obstruction or purge any air back to the main tank (probably flawed thinking). After idleing, i tried upping the throttle and it still worked fine. So I went for a ten minute test drive and everything checked out ok. So, I'm not sure what caused the problem or what fixed it, but it works at the moment. Stay tuned!

[John Schroader]

Not familiar with your system, but I'd venture to guess that your WVO filter is clogged. With clogged filter, car may idle OK but when it needs more fuel (upon accelleration) it will stall. May want to check this out.

[pgellers]

Thanks John. I ordered 3 filters yesterday for the WVO side of the system. I will have them with me in the car at the very least, should I need to make a change on the road. I'm sure that will happen at some point! Paul