Hi,

I am thinking of using a lift pump for my dual tank vegoil conversion, since vegetable oil, even when mixed with diesel is rather thick. With a lift pump, pulling it out of the vo tank, I dont have to worry about supply problems due to viscosity before the heater...

The thing is, I am not too familiar with the lift pump/injection pump setup on these cars.

Is the lift pump part of the injection pump? i.e. if I have one inlet hose going to the injection pump, will the lift pump pull fluid from whereever it originates, or is the diesel lift pump on the tank or somewhere else?

If I do go with a lift pump for my vegetable oil, what pressure and flowrate should I specify as output? As I understand it, if a lift pump pushes too much fuel through the injector pump, it can be bad news as too much pressure on the fuel input lines can cause IP seal problems.

Maybe I am overthinking this, it just seems to me that if I am pulling unheated, higher viscosity vegoil (albeit through a tube with a larger opening)up to the heater, and then lower viscosity vegoil through a smaller tube, the fact that the fluid is thick up through the heater seems to me that it will cause more stress on the injection pump, as it has to pull fuel harder before it can inject it. With a lift pump, it would assist in having enough vegoil there to supply the IP or depending upon design, the other fuel pump tacked onto the injection pump. The question is, what pressure would I want to feed the IP / IP with diesel lift pump so that it can always have enough without being overpressured or forcing pressure on the return lines... Perhaps 2.5psi?

Thanks,

JMH

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (116k)
1991 350SD (206k)
1991 300D (228k)
2008 ML320 CDI (199k)
1996 Dodge Ram CTD (442k)
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Past Diesels:
1983 300D (228K), 1985 300D (233K), 1993 300D 2.5T (338k), 1993 300SD (291k)