External smoke screw?

[sootman73]

I heard reference in other threads about a screw on the outside of the pump to get more fuel or smoke. what is this and where is it at?

 

[Ironman03R]

On the back side of the IP above the fuel lines. Its an allen screw with a outter locknut. If your pump is reman it will have a plastic cover over it. If it does, break it off, loosen the jam nut, and back off the allen screw 4 turns and tighten down the lock nut.

 

[Optikalillushun]

i assume this is for a factory turbo pump?

 

[sootman73]

what size allen wrench does it take? just wonderin not that important though. wow i never new that there was another screw to get more fel. wish i would have know this a while ago! now i really can't wait to get my truck back! thanks!

 

[Ironman03R]

Not sure on the size. All 92.5 and newer have the external screw.

 

[Optikalillushun]

hmm...interesting.

 

[f-two-fiddy]

Messing with it does nothing for performance.
It just meters more fuel than you can burn, during low rpm operation.Once the engine reaches 1700 RPM's, it is bypassed.

I'll repeat, IT DOES NOTHING FOR PERFORMANCE!
Turning it just makes low RPM smoke, and wastes fuel

 

[sootman73]

well im sure you understand that im 18 and i like to smoke. i like to make smoke without having to hammer down on the throttle. thanks guys.

 

[FordGuy100]

Messing with it does nothing for performance.
It just meters more fuel than you can burn, during low rpm operation.Once the engine reaches 1700 RPM's, it is bypassed.

I'll repeat, IT DOES NOTHING FOR PERFORMANCE!
Turning it just makes low RPM smoke, and wastes fuel

I'm going to disagree with you just for fun .

Anyways if you put in more fuel than you can burn, that results in more smoke yes, but it also results in higher EGT's. EGT's are a factor on spooling a turbo, the higher the EGT's the easier to spool the turbo, of course it will take into account air flow out the cylinders though. So at say 1500 rpm's and 600* EGT's will not spool a turbo as easy as 1500rpm's and 1200*egt's. Therefore if you turn up that screw your boost will rise quicker resulting in more power. Of course though, this thinking would only apply you would gain more power (not much, but definatly some) on a turbo IDI.

 

[f-two-fiddy]

Well the fuel does absolutely no good untill the turbo spools. So if you can get over 5 psi at under 1500 RPM's. Which I've never seen. Then you might get a bump.

 

[FordGuy100]

Well the fuel does absolutely no good untill the turbo spools. So if you can get over 5 psi at under 1500 RPM's. Which I've never seen. Then you might get a bump.

I'm just saying that the higher EGT's will cause the turbo to spool up sooner, so that you can start burning the fuel.

 

[f-two-fiddy]

You won't burn enough of that extra fuel, to raise EGT's high enough to help. It prolly slows things down a bit.

I messed with it for about 3 mo's. I'm back to within 1 turn of where it started.

 

[SKimballC]

I tinkered extensively with that screw on my turbo IP and it was nothing but an enormous waste of time.

 

[sootman73]

there are two plastic caps on the back of my pump. one that is offset a bit and higher up then one that is parallel with the truck and almost against the injection lines. i turned the latter out 4 turns and it cut my rpm to 2700! couldn't shift without letting off throttle and couldn't accelerate to save my life! did i turn the right screw? i dont think so but it did have outer locknut on it and was an allen head. anyone have an idea of what it is?

 

[high psi]

You turned the wrong one. The one you turned has more to do with the governor of the pump, hence your loss of RPM. The screw that was initially referred to is the offset, higher up one. It is referred to as the torque screw and is actually there to cut fuel output a bit over 3100 RPM. This in turn gives you a bit of torque rise when you are at a higher RPM and encounter a load. As you drop close to 3100 RPM you get more fuel and in turn more power, helping you with the load you just encountered.