GaCamper

On my 93 dually I've installed the fuel pin and made adjustments to the fuel screw, star wheel & smoke screw. Truck is running great.
Correct me if I'm wrong. Real fuel pump dummy here...
When turning the fuel screw in that increase the fuel pump pressure and the amount of fuel?
I turned the fuel screw in 2 1/2 turns.
How far can you screw the fuel screw in before you damage the pump or other things? Or does it really matter how far you turn it? From what I understand with the 93's the injectors are only going to let so much fuel into the cylinders..RIGHT?
How can you tell if you go to far in with the fuel pin?
With all that I have done max boost is at 15 psi with my foot into it. Running exhaust temps at 60mph is 540.....
Still running stock turbo & injectors...Haven't put under a load yet.
Thanks!

edwinsmith

Eventually turning the fuel screw in will cause the pump to runaway. It doesn't increase pressure, it increases the duration of the injected pulse of fuel. This happens when a collar slides back on a shaft that uncovers a relief port to cut off the fuel pulse. When you slide the collar to far the port never gets uncovered and runaway occurs.

You'll know when you're close to runaway when the engine won't idle down as fast or can't be adjusted down to a normal idle at all. BAck off some when you get to that point.

Edwin

GaCamper

Thanks for the information Edwin. I feel better now since I have a better understanding on how the pump works. This is a new adventure for me. I've never mess with a fuel pump before...So the fuel screw has nothing to do with the fuel pressure...Right? So I should be ok where I have it set then. Thanks!

edwinsmith

This page has a good description of how the VE injection pump works.

http://www.cs.rochester.edu/~jag/vw/...i/injpump.html

Edwin

gomerpile

but this was brought up to me by a good mechanic, if i turn this up will it begin to damage stuff, he said it was made for 160 horses and when you turn that up just a little you cut the engine life in half or so, is this true, or only if you let the temps get out of hand.

jjdiesel1990

yeah, gomer i've wondered that myself

rlyons

Not true at all, this same engine is used in boats, generators, and construction equipment and so on. It is adjusted for all kinds of different power levels. As long as you don't over do it and run it like a race car it will run longer than anything on the road. For sure keep a hand on exhaust temps.

wannadiesel

Only if you try to use all the power all the time. Think about it this way - most of the time you are using a tiny fraction of the engine's available power, and under normal driving conditions a modified engine is under no more stress than a stock engine.

GaCamper

My understanding to the set HP of the Cummins was due to the drivetrain. The drivetrain "tranny" is the weak link in the Dodge truck.

bigragu

It's about time I see another 1st gen on drugs on here. How long have you been runnin' propane, and what kind of results are you seeing from propane injection?

KRB

Boost seems low for the mods. You still have the stock 21cm turbo housing?

GaCamper

I've had the Propane system about about 3 years now. I really like it. I use mostly for towing when I need the extra power. I've notice about 4mpg gain also when using it and not towing.

GaCamper

I'm still running the stock turbo. I would of thought the boost would of been higher also. I've checked everything to make sure the hoses are tight. Haven't got around to changing it yet. I haven't hooked to our camper yet to see what the boost will do while pulling under a load.

KRB

Could just be the big turbo housing. I can't remember what mine was before I converted. Now I get 5 or less just running around but under a load it will go to about 25.

I guess the nest thing to check would be to pressure up the intercooler and check for leaks.