Not sure what gauges you're looking at but most are rated at 100psi.. I'm guessing you'd prefer something closer to 150-200psi.. Stewart Warner makes mechanical versions that go in that range.. If you're after an electronic version they've got one that goes to 150psi..
Very interested in this system. Everyone raves about the veggiestroke and I understand why, but I don't want to spend that kind of money and am looking to take on a project and really get to know my newly acquired 95 crew cab. I'm busy studying your plans and pictures and trying to figure it ll out. Keep us posted if you have any more news and/or details.
Yes, the mechanical CHEAP gauge I used was 100 PSI rated, but during the start process fuel pressure peaks to way over 100 PSI, and this tweaks the mechanical gauges. Seems there is some high pressure leakage from the injectors onto the low pressure side when cranking the engine. I could add a couple of more one way check valves to avoid this, but I think an electrical sender unit would be fine with these spikes.
I have attached a partial shopping list I used to piece together my system. This is NOT accurate, but is pretty close. I need to update this graphic. Please let me know if you are interested in an updated version.
At this point I'm very interested in whatever you've got!!!
Your system looks great and seems to be very simple. Aside from splicing couplers and hose connectors and what not, it makes sense to me. But yeah, whatever you've got for parts lists and schematics and info, I'll take it. I've got a 95 but I'm planning on converting the dino fuel setup to an electric pump (basically making it like the newer 7.3 setup) then installing my veggie system. This is really cool, thanks
Right now I think I get how most of it works, I'm just wondering how you route your return lines and how exactly the fuel manifold you're using works and how the purging goes. Do both the diesel and veg return to the veg tank? It's tough to visualize without seeing the actual parts and how they work, this is half the battle for me right now. I get a lot of what's going on, but it helps that much more when I can see it and touch it.
Edit: Looking at it more and more, your system may be so simple I can keep my stock dino system in tact... I think I'm getting it more and more. For a return on the veggie you are just using the check valves to keep the veggie from getting into the dino fuel and leaving the purge valve open so excess can go back to the veg tank? Then what for the reg diesel? With the veg pump off and the purge valve closed does the stock fuel system just circulate normally??? It's all very intriguing.
Yeah, I guess I need to explain how the system works.
First thing to understand is that this is a dead head system. That means there is no fuel return after the injectors. All fuel sent to the injectors is used. The pressure regulator(s) are before the heads, so we are only feeding the injectors the PSI they need. The only exception to this dead head is when I open the purge valve and fuel can dump back to the veggie tank. (diesel pushes the veggie out of the lines and head, then let motor run for about a minute to make sure all the veggie in the injectors gets used.)
My version of the 7.3 is a dead head system in stock trim. In my plumbing method I'm feeding the fuel into the front of the heads, and purging from the rear. Some folks feed diesel in from the stock lines, and feed veggie and purge from the other ends of the heads.
Some folks will get rid of the dead head design and use a pressure regulator after the injectors. While this is tempting for a few reasons, I think it is a more complex system, that costs more. There are advantages to each method.
The check valves are the core of this setup. Basically your diesel side stays stock and pumps at about 70 PSI. The Veggie system is setup to pump at about 5 PSI more then the diesel. This closes off the diesel check valve and only lets the veggie flow into the heads. The diesel is always pumping, and the extra diesel fuel is sent back via the stock diesel fuel return line. (My version of the motor has the fuel filter, water separator and pressure regulator all built into one unit, the fuel bowl. I'm not sure how the older 7.3 with the mechanical fuel pumps work.)
The Raptor pump I'm using has a built in adjustable pressure regulator that does not need an additional return line. This saves you about $100 on buying an adjustable pressure regulator plus the extra plumbing bits.
Hope that helps some. Please feel free to ask questions as I'm not the best at explaining things...
-Wayne
Quote:
Originally Posted by Cark
At this point I'm very interested in whatever you've got!!!
Your system looks great and seems to be very simple. Aside from splicing couplers and hose connectors and what not, it makes sense to me. But yeah, whatever you've got for parts lists and schematics and info, I'll take it. I've got a 95 but I'm planning on converting the dino fuel setup to an electric pump (basically making it like the newer 7.3 setup) then installing my veggie system. This is really cool, thanks
Right now I think I get how most of it works, I'm just wondering how you route your return lines and how exactly the fuel manifold you're using works and how the purging goes. Do both the diesel and veg return to the veg tank? It's tough to visualize without seeing the actual parts and how they work, this is half the battle for me right now. I get a lot of what's going on, but it helps that much more when I can see it and touch it.
Edit: Looking at it more and more, your system may be so simple I can keep my stock dino system in tact... I think I'm getting it more and more. For a return on the veggie you are just using the check valves to keep the veggie from getting into the dino fuel and leaving the purge valve open so excess can go back to the veg tank? Then what for the reg diesel? With the veg pump off and the purge valve closed does the stock fuel system just circulate normally??? It's all very intriguing.
You have done some fantastic work here but I have some questions.
My stock 2002 PSD has two check valves already installed by the factory in the stock fuel lines. Vegistroke installs two new check valves in the stock lines in series with the stock stock check valves. Total of four check valves are used for the stock system.
Your drawing only has the one check valve so my question is: Do you discard the original check valves and replace with new ones or do you double up the valves like vegistroke?
Why does vegistroke use two in line check valves in each head? What is gained?
You have done some fantastic work here but I have some questions.
My stock 2002 PSD has two check valves already installed by the factory in the stock fuel lines. Vegistroke installs two new check valves in the stock lines in series with the stock stock check valves. Total of four check valves are used for the stock system.
Your drawing only has the one check valve so my question is: Do you discard the original check valves and replace with new ones or do you double up the valves like vegistroke?
Why does vegistroke use two in line check valves in each head? What is gained?
Been a while since i have got out of the house, so to speak, but I think I can answer your question. The OEM "check valves" are not actually check valves they are pressure snubbers. They still allow a small amount of fuel to flow backwords through them. THey are there to prevent the pressure pulses of the injectors from backfeeding into the fuel system and preaking parts. Go ahead an connect a mechanical gage straight to the fuel rail and your needle will be all over the place. The very nature of the HEUI injection causes a pressure spike everytime it actuates. And since fuel is no compressible, and the iron fuel rail is not expandable, the pressure wave does not get dissipated. If not for those OEM check valves these spikes can be carried back into the fuel bowl, and pump. This is the reason why aeromotive pumps do not work well with a PSD. The composite vane in the pump gets hammered by those shck waves and eventually breaks.
Now don't take this out of context, I am NOT saying that removing those will cause your fuel bowl and pump to blow up, but the potential for other fuel system failures does increase. The point being, those are not true check vavles and do allow a small amount of backflow. Therefore we add our own true checkvalves to prevent any cross contamination. Oh yeah, we now use stainless checkvalves instead of brassCheers.
Oh and on the whole kit cost argument, I would like to point out that the base Vegistroke system has been the same price for almost 2 years, even though the product has advanced dramatically.
Been a while since i have got out of the house, so to speak, but I think I can answer your question. The OEM "check valves" are not actually check valves they are pressure snubbers. They still allow a small amount of fuel to flow backwords through them.
Oh and on the whole kit cost argument, I would like to point out that the base Vegistroke system has been the same price for almost 2 years, even though the product has advanced dramatically.
Ok I suspected as much but could not confirm this with newly obtained shop manuals. They just say it is a check valve with part numbers and explain what they are for.
So if I were to install Rotzuks system I would use the dual check valve approach like Vegistroke does. or checkvalve/snubber approach. Obviously it works.
Still will probably go with vegistroke but I need to know all I can for troubleshooting purposes.
I've got an OBS and wondering how this all will work with the mechanical pump and lines, how much they are different from the newer 7.3 setup with the elec. pump. Is the OBS also a deadhead system? Could I just use the check valves and then route the veggie system the same way as in the diagram??? I've had my OBS for 1 week and am still trying to figure out everything with the fuel system and how it all works. If anyone has a good link that shows a diagram of the stock fuel lines and everything that would be great. I think for the most part I understand it... but there may very well be stuff in there I'm unaware of or still confused on.
Older trucks 94-97 were not deadheaded. The fuel was regulated after it went through the fuel rails. Newer 7.3s regulated fuel pressure before the fuel rails. Thus the addition of the Snubbers or checkvalves as discussed here.
You might go to vegistroke.com and download the installation procedure for your model. I think you will find that the mechanical pump is replaced. I don't know if you can use the mechanical pump or not. Not an expert. Just learning about this stuff.
Yeah all along I've been looking into replacing the stock pump. I did DL the veggiestroke instructions and they replace the mech. pump with an elec. unit. If I switch to a regulated or adjustable electric pump will I then be "dead head-ed"??? This is an option I've been considering all along, so if it would make this DIY system work, then I'd certainly go for it.
Go look at frybrids web site. They have a powerstroke system and they state that they correct the deadhead problem with their design.
As I understand, if the fuel can only get out of the heads during operation through the injectors, it is deadheaded.
Right now yours is not deadheaded. That is because there is a route out of heads through a regulator and back to the diesel tank. Look at your manual for fuel flow.
Yeah, the frybrid system is basically the vegistroke, they actually even use the same FASS looking fuel manifold and what not.
I'm looking at the electric pump option and it seems like if I go with that then I only route the feed line from the pump the engine, and then split to the 2 heads? Then the return line just goes from the pump with built in regulator back to the tank? I'm confused on how this would get plumbed on an OBS with an electric pump and removal of the stock fuel bowl. Right now I think I'll be upgrading the stock system to a newer 7.3 FASS system with it's own filter and separator, but not sure how that works to return fuel to the tank. With the regulator in the pump and before the injectors, I can then deadhead the system? correct?
The stock check valves are a bit of a mystery to me. Upon inspection of mine and a couple of others, you can see light through them, and you can blow through them in either direction. If they are designed to reduce the spikes, that would be interesting.
I have removed the stock units from mine, and I do see a LARGE spike while starting. I do not notice any other spikes on my mechanical gauge. Spikes may be so fast that they do not show on the mechanical gauge?
I use a single LARGE check valve on the diesel side, and a single LARGE check valve on the veggie side. They are at my mixing manifold, rather then on the heads.
I would like to point out that I think the Vegistroke system is a great product, and has a fair price. I may have spent a bit less money putting mine together, but I have a lot more time and trouble invested. It would have been far faster and easier if I had ordered his kit, and I would also be able to enjoy his automatic operation.
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Cheers. 
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