Pre-Power Stroke Diesel (7.3L IDI & 6.9L) Diesel Topics Only

torque screw?

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Old 06-05-2010, 12:00 AM
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torque screw?

anyone know anything about this?

YouTube - Torque Screw Adjustment
 
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Old 06-05-2010, 12:06 AM
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I think only the 92.5 and newer IP's have the torque screw. It only seems to affect fuel output at lower rpm's. Some people have played with them and reported lots of smoke but no power and others have sworn to have felt a power increase.
 
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Old 06-05-2010, 12:09 AM
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hmmm might have something to mess wit tomorrow lol
 
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Old 06-05-2010, 12:15 AM
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Originally Posted by johnboggs21
hmmm might have something to mess wit tomorrow lol
let us know what you find!!
 
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Old 06-05-2010, 12:16 AM
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Make sure you are playing with the right screw. My truck should have a torque screw, but my IP was replaced with an older rebuilt IP by the PO and doesn't have the screw.

Is your pyro working yet, it's said toying with the screw will really mess with your egt's.
 
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Old 06-05-2010, 12:17 AM
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my guess is its the screw underneath the red cap on mine. It looks to be about in the same spot as the one in the video.
 
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Old 06-06-2010, 08:26 AM
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Originally Posted by johnboggs21
my guess is its the screw underneath the red cap on mine. It looks to be about in the same spot as the one in the video.
so what were the results johnboggs21?
 
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Old 06-06-2010, 09:58 AM
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The torque screw was only on the DB2-50XX IP's, 1992.5 and later trucks.
The engines should also run a serpentine belt.

The torque screw limits the amount of fuel delivered to the engine at low RPM's to help clean up the exhaust.
It does nothing to change the max fuel delivered, only the low RPM fuel delivery.

On a non turbo engine, most likely the only result from adjusting it will be increased smoke and higher EGT's.
On a turbo engine, it can help with low RPM turbo spooling and power.

Using both the max fuel screw and the torque screw together on a turbo engine will help with power across the RPM band.

Set the max fuel screw so the engine produces a light black haze at high RPM, in is more fuel.

Once you have that set, you can adjust the torque screw so you have the same light haze at lower RPM's.
On the torque screw out delivers more fuel at lower RPM, in decreases the fuel delivery at low RPM.

As with any IP adjustment, you should have a pyrometer installed before you adjust the fuel, high EGT's can damage the pistons.

Also the torque screw is set at about a 45 degree angle in relation to the IP drive shaft on the rear of the IP.

There is another screw that may have a cap on it, or a seal wire that is parallel with the IP drive shaft.
That screw holds internal IP parts in place and should not be adjusted.
IP damage would be the result.
 
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Old 06-06-2010, 11:58 AM
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I can get my truck to smoke pretty heavy with about half an accelerator application while getting up to speed but I've got newER injectors and the original IP so my timing is cranked way advanced to put good pressure to the injectors. Would turning this screw the other way net me any benefit untill I can afford a new pump?
 
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Old 06-06-2010, 06:12 PM
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well i turned that screw up today. It made a noticeable difference at takeoff, and noticeable black smoke. I need to turn it back down some. Cruising at 55, EGTs were the same as before.
 
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Old 06-06-2010, 06:52 PM
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Originally Posted by johnboggs21
well i turned that screw up today. It made a noticeable difference at takeoff, and noticeable black smoke. I need to turn it back down some. Cruising at 55, EGTs were the same as before.
do ya think your at 10.5 sec 0-60 now?
 
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Old 06-06-2010, 09:59 PM
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Depending on your axle gears, at 55 MPH you should be at or above the RPM that the torque screw has much effect on the fuel rate.


You probaby noticed the largest difference in smoke from say idle to 1500 RPM which is where the torque screw has the biggest effect.
 
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Old 06-06-2010, 10:54 PM
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Originally Posted by Dave Sponaugle
Depending on your axle gears, at 55 MPH you should be at or above the RPM that the torque screw has much effect on the fuel rate.


You probaby noticed the largest difference in smoke from say idle to 1500 RPM which is where the torque screw has the biggest effect.
you nailed it exactly Dave. Id say theirs no difference past 1500 rpm. After I first adjusted it and fired up the truck I had some black smoke at idle which cleared up after about 30 seconds. After that, just revving it in the driveway, it rolled more coal than I care for. Like I said, I need to turn it back down a notch. At least its easy to adjust.
 
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Old 06-06-2010, 11:11 PM
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Originally Posted by Dave Sponaugle
The torque screw was only on the DB2-50XX IP's, 1992.5 and later trucks.
The engines should also run a serpentine belt.
all of them? ive got a 93 turbo engine, v belt. did it come that way or do they change it over? i know the guy put the engine in his 88 f250. maybe he changed the drives over. id LOVE to switch to a serpentine belt.
 
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Old 02-13-2011, 08:41 PM
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I read this and I got a few questions. My IP is set so at very high RPMs there is a little haze of black smoke. How much should I thread the jam nut in for a slight haze of black smoke in lower RPM's? Close to 1/2 a turn more like 2-3 turns on the jam nut?
 

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