Torque screw? - Diesel Forum

jacksonguitars4life · 12-03-2012, 04:00 PM

is it located under a plastic cap from the factory? I wanted to make sure mine is adjusted properly for the turbo, and where its supposed to be is a plastic cap that i dont wanna break off if i dont have to. also i suppose if thats it, then the cao being there tells me its still adjusted for na. its a 93 btw so it should have it

Evel486 · 12-03-2012, 08:45 PM

There should be 2 plastic caps. The torque screw is under the larger one towards the drivers side- sticks out at an angle. The smaller horizontal one in the center is the guide stud. The correct adjustment of the torque screw for a turbocharged engine is backed out of play. There should be at least 1/4" of screw visible above the jam nut. On N/A pumps the torque screw is usually just below flush.

jacksonguitars4life · 12-03-2012, 10:15 PM

yep that was the one. it used to be na, and it was never adjusted, so now i got a 1/4 in sticking out. cant tell a difference but makes me feel better knowing its adjusted properly

tanbuddy · 12-09-2012, 04:01 PM

does this screw adjustment actually give u more power on the bottom rpm rage or more throttle response like taking off a puff limiter on a old mack?
What was its intended purpose from the factory

Evel486 · 12-10-2012, 12:38 AM

The torque screw cuts the max fuel back a bit at about 3100 rpm to reduce black smoke. When adjusted properly it has no affect below 3000 rpm. Of course it is not needed on a turbocharged engine.

tanbuddy · 12-10-2012, 07:00 AM

mine does smoke a little on the top end maybe the last owner messed with it. Truck runs great otherwise

LMJD · 12-10-2012, 07:18 AM

Quote:

Originally Posted by tanbuddy

mine does smoke a little on the top end maybe the last owner messed with it.

No doubt, screwing the torque screw all the way in or whatever "for more power" has been passed around IDI forums for years by those who don't know jack poop about a IP rather than take advice from someone who works on'em for a living like Evel486.

RacinNdrummin · 12-10-2012, 05:48 PM

The "Torque Screw" is just a metering valve limiter and it does cut fuel at ALL RPM's WOT... At partial throttle, Depending on where its set, it could limit fuel... The Idea is to limit particulate emissions under heavy load situations, without limiting total max fuel capability, thats why it was utilized. It basically puts more of an RPM bias to the fueling, instead of a throttle bias...

Backing the torque screw out is simply the same setting as an earlier non-torque screw pump...

**NMB2** · 12-10-2012, 06:01 PM

Quote:

Originally Posted by RacinNdrummin

The "Torque Screw" is just a metering valve limiter and it does cut fuel at ALL RPM's WOT... At partial throttle, Depending on where its set, it could limit fuel... The Idea is to limit particulate emissions under heavy load situations, without limiting total max fuel capability, thats why it was utilized. It basically puts more of an RPM bias to the fueling, instead of a throttle bias...

Backing the torque screw out is simply the same setting as an earlier non-torque screw pump...

Exactly Right.

Xeonpony · 12-11-2012, 09:34 AM

Quote:

Originally Posted by LMJD

No doubt, screwing the torque screw all the way in or whatever "for more power" has been passed around IDI forums for years by those who don't know jack poop about a IP rather than take advice from someone who works on'em for a living like Evel486.

Well didn't you know? It is a rule on all engines, if there is a screw and you screw it in it "ALL" ways gives more power!

Some people you can't get the common sense in even if you use the engine to push it in by liberal aplications over their heads, seems to apply to electronices as well, trying to fix a board where they figured turning every pot to full right hand would some how make it work better <_<

tanbuddy · 12-11-2012, 04:03 PM

Is there any good pictures on here of a pump and all its parts labeled? I think i found mine, its in the back of the pump and backd out a little

jacksonguitars4life · 12-11-2012, 04:28 PM

tanbuddy there is a vid on youtube describing the procedure

Torque Screw Adjustment - YouTube

I can tell absolutely no difference. But some trucks may be different than others

Evel486 · 12-11-2012, 08:34 PM

I just watched that vid- that guy has no idea what he is doing. The adjustment he did will do absolutely nothing- that is a turbo application and the torque screw is already out of play. The screw has to be about flush with the jam nut to start working.
The torque screw is an emissions thing and was only used on 1992 1/2-94 natural aspirated engines. In most cases backing the screw out will make very little noticeable difference- perhaps a bit of haze under heavy load at higher rpm's. It will NOT increase hp.

RacinNdrummin · 12-12-2012, 12:43 AM

Quote:

Originally Posted by Evel486

I just watched that vid- that guy has no idea what he is doing. The adjustment he did will do absolutely nothing- that is a turbo application and the torque screw is already out of play. The screw has to be about flush with the jam nut to start working.
The torque screw is an emissions thing and was only used on 1992 1/2-94 natural aspirated engines. In most cases backing the screw out will make very little noticeable difference- perhaps a bit of haze under heavy load at higher rpm's. It will NOT increase hp.

This is right on. The screw must be flush to have any result, and the result is less high load particulate matter... With the max fuel screw backed off as it is on a stock pump, backing the TS out will result in very little, however, the further you crank the max fuel screw, the more of a factor the TS becomes... Though not as much as it gets credit for. On DB2's, the metering valve isnt much of a limiter, so even with full plunger travel, the TS doesnt have much effect... It was just a way to externally adjust particulate matter emissions, while still retaining the max fueling setting...

LMJD · 12-12-2012, 09:22 AM

Quote:

Originally Posted by Evel486

I just watched that vid- that guy has no idea what he is doing. The adjustment he did will do absolutely nothing- that is a turbo application and the torque screw is already out of play. The screw has to be about flush with the jam nut to start working.
The torque screw is an emissions thing and was only used on 1992 1/2-94 natural aspirated engines. In most cases backing the screw out will make very little noticeable difference- perhaps a bit of haze under heavy load at higher rpm's. It will NOT increase hp.

That's pretty much the "advice" that's flooded different forums that I was referring to. As someone stated years ago on a gun forum, anyone who takes advice without knowing the advisor's qualifications and experience is a fool. IMO, it's worse than asking a complete stranger on a street corner, at least there you can get a visual.

When it comes to pump advice for me, it would be from you or a phone call to the local pump shop.