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Discussion Starter · #1 ·
i need help to adjust my fuel+ air mixture on my 3b diesel engine. i want to get more mpg. how do i do it and where is that adjusting screw. do i adjust the amount of air or amount of fuel that is injected. thanks
 

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Your best not to adjust anything. Leaning out the fuel will get you better milage but it will kill the power drastically. At any rate before playing with the main injection volume screw, you should get a pyrometer so you can see where your exhaust gas temp is. Move the screw too far out and you'll burn valves. Too far in and you have no power
 

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I've stayed away from doing that too, i saw a 2L where the guy was running so rich the exhaust was black as night at idle. Unless you know what you are doing it is one of those things to stay away from.

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470,800 and rising
I am the black cloud of somke that flies by at 3500rpm!
(Please note diesel smoke is dangerous so lay off the throttle!)
 

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Now , I'm not a diesel guy, but isn't it possible to advance the pump like you can do with domestic diesels.
You would still need to know exhaust gas temp or risk destruction.
When I was an apprentice at a large GM dealer I remember guys were always bringing in their trucks to have the pump advanced a few degrees in order to gain power and milage.
We didn't have a pyrometer and the pump was just advanced a set amoumt, measured with a small metal ruler.

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75 FJ40, 4 inch BDS springs,1inch body, 35's, detroit locker, power steering, disc brakes, 3spd low range gears, full cage, XD9000i, extended shackles, dual batteries....you get the idea.
 

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Yes this can be done, I used to have an article on it but I lost it last time the computer went down. I've got a friend back east that has done this I will try to get the info from him. I think he said he picked up a few MPG after the adjustment. If thats all you want then you dont have to worry about the pyro, only when increasing injection volume
 

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Discussion Starter · #7 ·
still waiting for instructions to adjust fuel mixture or advance timing adjustment. thnaks
 

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My info was for GM diesels, I can get it if you want but I don't think it's what you want.
Tune the motor, get the pump calibrated, and run it.
It's not worth a few mpg to melt pistons to the bores.


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75 FJ40, 4 inch BDS springs, 1inch body, 35's, detroit EZ locker, power steering, disc brakes, 3spd low range gears, full cage, XD9000i, extended shackles, dual batteries....you get the idea.
 
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