How to adjust the fuel screw

[texcl]

I backed my fuel screw out just a touch after I resealed my I/p to lower my RPM'S which it did and she runs great now. I was wondering what are the benefits of running the screw in or out, I assume if you run it in it has more power and smoke and out it would be better mileage or am I wrong?

[TylerDurden]

Bingo.

IN = more fuel per injection.

Dark smoke = more power, with less efficiency.

[bbob203]

which is the fuel screw?

[TylerDurden]

Fuel screw (full load stop screw) is by the cutoff solenoid.

[bbob203]

if I was inclined to adjust mine for better mpg's how much might I think about screwing it in?

[TylerDurden]

More mpg requires fuel screw going out... less power, less smoke, less fuel.

[bbob203]

should I advance my timing? idle?

[TylerDurden]

IIRC, idle will need tweeking if the fuel screw is adjusted - more fuel will raise the idle speed and vice-versa.

[damac]

Is it wierd to find that the stock setting is best on used pumps?

I have messed with 3 in my short vw life and they all started with locked fuel collars.

I tried just a turn in/out and found either the car lacked power and was unsafe to drive, or the car revs would hang. Like idling on a flat straight in 3rd gear through town, a cruise control effect

Either way I could tell something wasn't right in either case and always ended up back on the stock position?

[TylerDurden]

I tried just a turn in/out and found either the car lacked power and was unsafe to drive, or the car revs would hang. Like idling on a flat straight in 3rd gear through town, a cruise control effect

Increasing the fuel will raise the idle significantly. I screw it in to get loads of smoke on full throttle, then dial back the idle.

Then, I just need to exercise discipline with the right foot.

[Ira B]

My own experience with adjusting the total load screw (which is limited) is that a very small adjustment makes a big difference. I adjusted mine for better mileage and got the most satisfactory results at about 1/4 turn out from stock.

[the man 53]

I seem to adjust mine to run the best it can with little to no smoke. Anytime I have unscrewed the main screw I didn't work for me. If I have less power but still need to climb that hill my right foot is in it all the way and I am downshifting. If it runs good but doesn't smoke much all you need to do is be mindful of the right foot and you get better mileage. Even pouring tons of fuel with my turbo in my 86 jetta, once I intercooled it I averaged 45mpg. If I wasn't mindful my worst tank was right around 34mpg.