Could running so much fuel pressure cause the IP to sieze?

I was running veg with a Holley Blue gasoline pump. It made almost no pressure and the truck would starve up hills on the highway. I fixed the problem by opening up the vane to rotor clearances and it worked great!

After modifying the pump (and doing some other work), the IP busted its shaft. I replaced the IP and started installing lots of gauges to see exactly what's going on. Until everything is 100% I have not been running veg. Well I got a gauge between the lift pump and the filter and turned on the veg. I got 17PSI!!!! I quickly switched back to Diesel (Diesel uses the stock lift pump). I have a fuel pressure regulator to install tonight and will set it to 7PSI. I'll also be installing another pressure gauge right before the IP.

I don't know about your motor, but on a Dmax, a hot lift pump like that will cause all kinds of problems. I knew a guy who put a Glacier Diesel lift pump on a Dmax (ran about 14-15 psi) and that thing was bucking, surging, and stuttering so bad that could barely make it down the road.

Hey Donnie, why don't you see if DieselPro on the 6.5 forum can answer this?

Hey Donnie, why don't you see if DieselPro on the 6.5 forum can answer this?

I PM'd him about it. He feels that 10-12PSI is as high as you should go.
Since my stock Diesel lift pump makes 10psi at idle, I'll set my veg fuel pressure regulator to less than that.


10 t0 12 psi should be O.K. When you run 17 the pump will be fine till you tach it out. When the internal pressure exceeds 120 psi the pump can seize.

I do not reccommend veggie or bio fuels so you are risking failure every time you use it so be warned.

I PM'd him about it. He feels that 10-12PSI is as high as you should go.
Since my stock Diesel lift pump makes 10psi at idle, I'll set my veg fuel pressure regulator to less than that.

That's a good idea. DieselPro knows his stuff.