Converting Frybrid back to original
 

I just got a very clean 1982 Mercedes 240D with a Frybrid WVO system. After researching this company I see that it is no longer in business. I made the mistake of attempting to switch over to WVO from biodiesel and experienced an air lock that after days of attempts to clear, convinced me to revert back to straight bio-d and decommission the Frybrid system completely. I want to bring this car back to its original system, running on bio-diesel only using factory design.

My question is, Does anyone have a fuel line schematic for the original system so that I can correctly revert the wacky Frybrid system to Mercedes factory operation?

I downloaded Frybrid's fuel routing schematic and found a Haynes Manual that assumes I already have factory lines and hoses in place. Diagrams in this book are poor and pictures fuzzy. I've included the Frybrid schematic for your perusal.

Any assistance would be appreciated.

Yes, I have never laid hands on one, but am familiar with at least the design installation. I was an active participant in the frybrid forum and ran and modified an SVO system on my 240D, and will do the same on my 190D shortly. If you're not too far from Buffalo, NY, could I pick up or cover shipping on the remains?

The frybrid system uses a coolant heated supplemental fuel system to provide heated vegetable oil to the injector pump at a design temperature of 160F or higher. Once turned on it switches from diesel to SVO when the coolant temperature reaches 160F. A purge button is used to flush SVO from the injector pump about 30 seconds before you stop and turn the motor off.

You should find coolant, fuel and electrical additions to the stock system.

Does it look like there is an electrical sender on the aluminum fuel tank in the back?

The design installation of the frybrid system uses a spare fuel tank with coolant heated pickup and aluminum tube in hose (TIH) WVO fuel lines, a heated SVO filter and a 'final' heat exchanger- either a coiled tube in shell or flat plate heat exchanger (FPHE), probably installed near the engine.

2 or 3, depending, Hydraforce solenoid valves, probably installed near the engine. (Black or silver metal squares with 3 ports and 1 or 2 wires. You should be able to follow these wires to the frybrid electrical controller)

So, there's a bunch of things not supplied by mercedes, coolant, fuel electrical. They should tee into the respective lines, and you can disconnect these things at these points. I would love it if you could do so with a little care and I could take these things off your hands.

There are also some changes made to the hose routing to the lift pump and the stock fuel filter because the lift pump was shared by the diesel and SVO fuel systems and the passage between the fuel return line and the diesel filter should have been blocked to prevent cross contamination of SVO into the diesel filter. You might need to replace the hollow bolt on the stock filter.

To avoid splice points, I'd just replace the lower coolant hose and coolant line from the back of the head to the heater control valve. These are the points that were probably tapped to supply coolant to the frybrid system and return it.

Electrically, you probably just have a wire tapped to IGN HOT (12V if the car is turned on, like the radio) feeding the Frybrid controller.

Fuel wise, I'd just replace the fuel lines, running one from the hard line to the (lift pump or filter) and one from the return to the hard line.

There's some particulars, I'll take a look at my 240D and notes and sort it out.

Ben, if you decide to sell that Frybrid system, I'd be interested in it.

The system is simple, air locks are really not possible. You should simply clean out the system and refill it with vegetable oil, there is likely old contaminated oil gelled in the tank or a line from sitting. The manual clearly states that if the vehicle is to be stored, the Vegetable oil should be removed and the system purged with diesel fuel. I just revived a system that had been sitting for 6 years by simply cleaning it out.

Attached is the additional manual for Mercedes vehicles that would have come with the kit, it shows the original routing.