1st Generation Dodge Cummins 89-93 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with Rotary Injection Pumps

power screw adjustment issues

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Old 02-10-2019, 07:14 PM
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Default power screw adjustment issues

Im having some problems and I need your guys help. I have a 1992 dodge w250 and I've done a few minor things to it. first of all, I put a 3200 governor spring and stage 2 fuel pin in. I drove it awhile and noticed it was leaking fuel out the rear rubber vent so I took the pump top off and put in some new o - rings. While I had the top off I wanted to put a Hot screw in it for the hungry diesel ( my stock fuel screw got pretty gummed up from the collar and it messed the threads up on it), so I bought a new screw. I put the top on, took a few tries to get the throttle lever in the right spot but I think I finally got it pretty close. I wasn't able to get any exact measurements on how far my stock power screw was screwed in before so I screwed it in to about where I thought it was stock and I was going to start turning it up once I got it running like it was before I had the top off. I got it running, and started turning the power screw in. I would rev it up ever turn of the screw, trying not to get a run away. the throttle wasn't hanging up when I would rev it up so I kept on screwing in. Well, it got the point when it started idling down and finally died. I was stumped. I later found out that the inter-cooled '92s don;t always run away. I still don't fully understand why it dies when I turn the screw in clockwise. i ended up backing the screw out a few turns to where to would idle fine, so I took it out for a test drive. I could only get it up to about 2000 rpms, it would build about 10lbs of boost. And my fuel pressure was at 15 psi. once I got home, I backed the power screw out more, and after several test drives and screw turns counter clockwise the rpms would be able to climb more, and i was making more boost. Now currently, the screw doesnt seem to be in very far, little to no tension on the screw from the spring loaded lever inside, and im only able to get it up to 2500 rpms, with about 22lbs of boost, and my fuel pressure drops to 12psi ish when I floor it. Im confused about this deal, hoping you guys can give me some ideas. I did mess with the star wheel alittle, i was running it with quite a bit of pressure on the spring so I backed it off a few rotations. getting alittle puff of smoke before the boost kicks in so I know im getting bottom end fuel atleast. I guess I need to know if you guys have any ideas about the power screw, and what I can do to get back to 3200rpms instead od 2500. Thanks guys
 

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