Hi all my dad just bought a 91 with five speed and I was looking at turning up the fuel I got the instructions and I put a wrench on one of the two lock nuts on the full fuel screw and it turned super easy. both nuts turn is it suppose to be that way? I turned it in about one turn and the idle came up so I assume it was doing something. How much can I go in with the screw? Thanks in advance.

 

the more you turn the more idle will need to be brought down. id say another full turn and bring idle down and see if you like it.

jiMMy

 

Is it possible to go to much?

 

yes, your truck will not return to idle and be clasified as a run away, most go 1/4 turns at a time. mine is 1.5 turns in from stock

 

Just a heads up on the "run away".
You do not want a "run away" situation. When you have a "run away" turning the key to the off position may not turn off the engine. The manual shut off lever may not work and the only way to kill the engine may be blocking the air to the compressor.

So go easy with the fuel screw.

 

ummmmm..... I think I'm 'having a moment" here....

but...the last time I looked there aren't two locknuts on the full fuel screw. The only one that has two is the high idle or governor screw.
The full fuel screw has a single 13mm locknut and a small 6mm hex tip on the screw end itself....
So if am correct we have: high idle screw = two 10mm locknuts;
idle screw = one 10mm locknut; fuel screw = one 13mm locknut; smoke screw = one 13mm locknut.

you can test for the approach of runaway too... after adjusting the fuel screw, start the engine and slowly open the throttle up...approach the 2000 RPM mark and when you get to it, hold steady for a few seconds... if the engine RPM continues to climb on it's own, no matter how slowly it does it, you are close to runaway.
On a couple trucks I've had to use this method but bring up the idle to roughly 2200 - 2300 RPM and then hold steady.
Try it out...

bob.

 

Thanx for the runaway test Bob. I've been been playing with the pump this week and felt like I was real close. Trust me, you haven't lived until you have been behind the wheel of a runaway. It happened to me TWICE in VW diesels. (For the record, it happened after some guy named Calvin messed with those funny looking screws on top of the injector pump and squeezed a little more power out his VW. But I don't know anyone with that name )

 

Bob the screw that I was adjusting was just above the fuel injector lines and just below the afc they are 13mm I did not have to loosen the lock nuts to turn it is this normal?? Thanks for the tip on checking for a run away,

 

Just looked at dodgeram.org and they call it full power adjustment not full fuel that one looks like it is under the afc cap

 

I'm with Bob, I think you're playing with the high idle screw. The fuel screw is buried on the backside of pump, the locknut is 10 mm and the screw itself is 6 mm. It's probably still got the cap on it.

 

I just checked on the tdr and there is a gov spring thread with pictures and what I am adjusting is call the full fuel screw not the high idle which is on the outside of the pump.

 

Yup, there are only two adjustments that have a 13mm locknut....
One is the full fuel screw and the other is the smoke screw.
The smoke screw has a torx bit (#25?) and it's lock nut is 13mm.

Now if the fuel screw locknut was loose that is not good. That screw could have moved in pretty much any direction depending on how tight the threads are.
Also, I won't say it's never been the case, but I have never seen two locknuts on that screw.
Either way, you want to snug the 13mm up. It doesn't have to be knuckle buster tight, just snug is all.
I had occasion to do the runaway test just tonight on my brother's truck.
We only got to 1600 RPM before it started to exhibit signs of runaway.
In his case the new governor spring did not respond right away...
The engine continued to climb to about 2600 RMP then the governor spring started to pull/release, pull/release. It did basically stop the runaway at that point but it was on/off, on/off in function.
Keep your eye on this condition it can be a bit scary if you're not prepared.

bob...

 

Thanks for the info bushy I will check it out and tight the locknuts

 

As an update on the runaway topic.....
On Thurs nite my brother was in for a retorque on his head after the twin's/stage II o-ringed head install....
We did the runaway test on his.... I got to about 1500 RPM and it would hesitate for a few seconds then start, slowly, to climb and then quickly increase the rate of climb.
It would go as far as about 2600 RPM then the heavy governor spring would grab the pump and pull it back a couple hundred and release..then grab, pull down and release...
I believe that the governor spring is so firm that it can't respond soon enough and smoothly enough to slow and then ease back the RPM climb.
The truck did not exceed the 2600'ish level though....
His trouble now is more fuel... he can hit 40 psi with the wastegate blocked off but can't break 900 - 950*F on the pyro...
Hmmmm...... more fuel...

pb...