Hello,
I need some help!
I am converting a 1986 Military Blazer which has a 6.2L in it.
I have a 2 tank system. The second tank is in the back of the truck and I have run heater hose all the way to the back for heating the tank and filter. I ran all of the hoses together so that the WVO will stay hot.

I have a electronic fuel pump mounted near the 2nd fuel tank. WVO is sucked out of the 2nd tank and pushed into a preheated 2 Micron filter. (I pre-filter at .5 Micron)
I have a Pollak fuel switch mounted near the mechanical fuel pump in the engine compartment.
I have WVO at the electronic switch. The hoses all read over 100 degrees. (heater hoses running a lot hotter).
When I make the switch to the WVO, the motor dies in about 2 or 3 seconds. It almost seems like it is not getting any fuel.
I am confused about a couple of things:
Do I need a electric fuel pump for the second tank? Do I have stalled in the right order? (2nd Tank, Pump, Filter, Switch, Mechanical Fuel Pump, Injector Pump)
Where is the better place to tap into and install the fuel tank switch?
Any pointers would be appreciated.

Steve

I did get this to run, but still had issues in the end. I was able to flip the switch and run for a few seconds at a time initially. I then took the truck down the road for a test run. It does run a lot quieter on WVO! However I did loose HP and when I flipped the switch. The motor would not idle properly either.
On my test drive, I blew the mechanical injector pump. I am thinking the shaft broke. I also noticed that I have antifreeze pouring out of the cylinders when the glow plugs are removed. Yup - cooked a couple of head gaskets.
I will pick up this project as soon as we do a motor swap. The swap should be completed in less than 2 weeks. Hopefully, I can get some help from someone who has experienced the slow, low performance when running WVO on the 6.2. Anyone ever replace a 6.2 with a 6.5? I hope that the 6.5L long block that I have fits in the 6.2L's place. Should still be the same block..?

Looks like you have several things going against you here. One I think you have water in the WVO(thats how the pump seized)second you need to have the WVO at 150 degress before entering the IP. I know of several guys who have heat exchangers in the WVO tank and also a vavle block with glow plugs to heat the WVO before the IP. If you do a search on this site for 6.2-6.5 IPump died-killed-seized you'll see it is right after switching to WVO at speed(water in WVO) I have several 6.2,6.5,6.5TD I have studied this for a long time. GM pumps are very fragile. Heat the WVO!!!

quote:

Originally posted by stepmo:
Anyone ever replace a 6.2 with a 6.5? I hope that the 6.5L long block that I have fits in the 6.2L's place. Should still be the same block..?

Not quite the same block, but interchangeable. The 6.5 has stronger webbing in the bottom end.

Thanks for all of the help.
As Dieselherb points out, I will need to heat up the WVO more. I was only at 130ish with my heater hoses method... I agree that I should have had hotter WVO. I like the glow plug idea. I may purchase a couple of those unless someone knows how I can make one. I also want to put a oil filter heater on the system.
This is a project truck. Well at least the first motor was. It has had bad head gaskets, or something worse, for 2 or 3 months now. That is why I have a spare 6.5 in the shop. I wanted to run WVO on the bad motor to see if it would actually work. It did.
So, the 6.5 should be a straight bolt up in the 6.2's place? Am I understanding correctly that it will bolt up to a TR400 too? When you speak of "webbing" what are you referring to? These are Military vehicles and motors. Very basic motor. No computer with the exception of the GP controller. This is a complete long block. Manifold and IP are already installed. This motor was tested but never reinstalled back into the Military Humvee. I hope that the exhaust manifolds from the 6.2 bold on to the 6.5. The long block has Humvee exhaust manifolds on it right now.
Is there anything that maybe a "gottcha" that I should be aware of when or after I complete the bolt up? Any special pre- starting instructions? I know that I should probably pull the glow plugs and prime the fuel system. Anything else that anyone can think of?
TIA.

Stepmo,
Yes, the 6.5 will bolt right up. fits the trans too. Webbing is the part of the block where the main bearing caps bolt up. Manifolds will work too. The only other thing, military glow plugs are 24 volt. replace them with good 12 volt GP's. HTH

Thanks Joe!
Hope to take the truck in this weekend and have it up and functional by this time next week. It will run on 100% Diesel for a few break in miles first. That will give me enough time to get some additional heat on the WVO fuel lines.
I can't wait to take apart the 6.2 and see what damage was really there before the WVO attempt.
Water in the WVO was mentioned and I also read about how it will break an IP pretty fast. With the exception of a water separator, what else can one do? I am pre-filtering in the shed at .5 Micron and have a 2 Micron Bio-Tek filer in between the second tank and its pump and the injector pump. I thought that would be plenty.
These motors also have a mechanical fuel pump. When I added the second tank, I placed a 65PSI fuel pump at that tank's location. I pump it to the Pollak Switch under the hood. Is that too much PSI for the stock IP?
I am also going to go with the modified loop and install a second Pollak fuel switch for the purge. At least that is my thought process.
Steve

I think my problem is similiar

I have installed 3 wvo systems in my life none have given me as many problems as my 6.2. I can’t seem to figure out the problem. This is what is going on. I have a 32 gallon tank in back with HOTFOX. Then it hits the Vegmax(Raamco heated filter) then pollak valve then Vegtherm then lift pump then injection pump.

Problem : It seems like I am clogging filters I drive for like 150 miles then it starts to go voom voom voom (Hunting).
Especially when I step on the gas and all of a sudden jump off the gas then it really does it, Some times this produces a stall.
Starts fine Idles fine, but under load it chokes and humms driving me freakin nuts. Also I could drive around town at like 25 to 30 miles an hour without having a problem especially if I am steady with the gas pedal.

Tried to fix it by : Installing a 5-9 PSI electric pump in the back right after tank.
Replaced the hose after the vegtherm with metal fuel line because it was collapsing because of heat(I think).

Your help would be greatly appreciated.

stepmo,

I have a 6.2 with factory dual tanks. It had electric pumps in the tanks but I removed the pump in the WVO tank after it died twice. Now I have the in-tank pump on the diesel tank and I run the WVO through the original mechanical pump on the motor. I start-up and shut down on diesel. The only heat I on the WVO side is a short heat exchanger (a 4" dia. Stainless pipe about 7" long with 3/8" stainless tubing coiled on the inside) right before the mechanical pump heated with the engine coolant. Works great for me although I do not drive it if the temps go below 25 degrees. I run a 90/10 or 85/15 WVO/Reg blend.

I have my Pollack valve after the pumps and filters ( pumps then filters then pollack valve). I also have a 12 volt valve after the filter(on the WVO line) that is open when I am on diesel which lets the mechanical pump recirc straight back to the tank. I believe this heats the WVO through the filter before I switch over and keeps the mechanical pump from dead-heading and building up pressure. I have the WVO and the diesel set up as completely seperate systems until the pollack valve. Each has it's own pump and filter.One pump and one filter per side.