I have a '78 Econoline E350 Camper Special (It's a mobile kitchen now). It has a turbocharged 460 with a Holley, MSD 6BTM, and Edelbrock Vara-jection. This is how I got the truck. The guy that did most of the work owned it before the guy I bought it from. The guy who owned it prior to me "did what it needed - nothing more". I think that means he changed the oil and put gas in it...
I'm certain that my turbo is not working as my boost gauge will only ever show vacuum. The Vara-jection is hooked up but there's no water in the tank. The pump light on the Varajection box does come on when I'm on the gas. The truck runs like molasses (in lieu of more colorful language). I'm thinking about just stripping the engine down to stock-ish, tuning it up, making it run RIGHT, then slowly adding the mods back in.
Until I remove and refurbish or replace the turbo, do I:
a) put water in the tank.
b) disconnect the control box but leave the system plumbed in
A) I would put water in the tank after cleaning it out as there will be scale of some time that'll have formed from just sitting, the system will will plug with the least amount of "mung" and render the jetting useless.
I'm sure you have winter windshield washer fluid in your state believe it or not you can use that because it has a mixture of water and alcohol in about 35% dilution. I'm not fully sure how your water injection is set up (I'll Google it) BUT, if it comes on and works even without the Turbo it'll be awesome. If it were me I'd be looking to see how I could run the water injection all the time off ported vacuum, even without the turbo the engine will thank you.
B) No I wouldn't disconnect the control box just yet because I'm thinking it's working on engine vacuum and if it is then you already have your metering device and you don't need to look for an alternative way to "turn it on and off"
C) the only system I personally would remove is the turbo, you are running a food truck, I'd think you are looking for efficiency and best performance with least problems.
D) don't leave it as it is get the water injection working even the engine will love it AND it'll begin to perform more like it's alive.
A big block with water injection, even "Old School" that's a little bit of heaven you got there.
Robert in Canada