Hi there Forum Fiends, I'm helping a friend try and troubleshoot an issue he's been having with his '84 300D-T losing power while running biodiesel versus petrodiesel. The biodiesel is good quality ASTM-certified commercial stock, so I don't think fuel quality is the issue... A mechanic wanted several hundred bucks to open it up and diagnose! I'm thinking it can't be that complicated... Can it? Does anyone have any theories as to why this would occur?
I have a THEORY that it could possibly be his fuel lift pump going bad... Could THAT cause such a power loss with the higher viscosity of the biodiesel taxing a worn lift pump? (I also suspect the lift pump because a slightly shady mechanic my friend had work on the car right when he got it actually installed the fuel line ahead of the lift pump with a KINK in it - which took us a little bit to figure out, such a dumb mistake by a "pro"! So the lift pump was being choked off for a bit...)
Anyhow, any input would be appreciated to help us get my friend's sweet maroon cruiser back on 100% biofuel! Cheers!