Here we have it, all info, hard core tech or not, and issues you may encounter. What makes a 12valve such a cool engine to tinker with. This section is for the P-pump 6BT's from 94-98, and also covers most any other engine that this pump went on. Hopefully will help the new diesel owners understand their fuel system a little better. Get gauges, and a good aftermarket tranny or clutch before adding power, that's the #1 rule!
-I'll start with the link to the how-to article I made about sliding the fuel plate and/or grinding one:
-Here's an article on how to shim the gov. springs:
You can also tighten the stock ones 1-4 "clicks", or purchase a gov. spring kit. Just my 2 cents here, but for those looking to purchase a GSK, a 3k kit for manual tranny trucks, and 4k for automatics are guidelines for a typical street driven truck. They are made up to 6500 rpm, from what I remember.
-AFC adjustments are covered in the fuel plate article. Then, for those that have a #0 or 100 plate, you'll need to take off the whole AFC housing and match the fuel plate profile to the little leg on the AFC.
-Fuel rack stop, there's a plug at the front end of the pump for adjusting full rack travel. You have to loosen the pump from the timing case to get it off though. Some people have made a thicker washer, or doubled up the washers to achieve the increased rack travel.
-Timing, how far advanced will depend on how much power you want and where in the rpm range you want it. And here's a link with info:
-KDP(killer dowel pin) the enemy of the timing gears. Timing case has an alignment pin by the water pump that can fall out unless it's been fixed with either the jig or a tab.
-delivery valves are in the top of the pump, just under where the injector lines attach to the pump. Bigger del. valves are sold, and typically the .191's are an upgrade over stock. There's also laser cut ones for those that cant seem to make enough black smoke.
-Overflow valve is on the top corner of the pump by the oil filler. Also called pressure relief valve. If it gets weak, the engine will puff white smoke, be hard to start, and a few other issues. You can stretch the little spring inside, but sometimes it's better to just get a new one every 150k miles(give or take).
-Fuel shut-off relay in the firewall above the intake manifold. Ususally there's 3, sometimes just 2. Original ones say HiRam on the outside of the relay. When it's bad, it'll crank & not start at all or sometimes it will/ sometimes it wont. Good to keep a spare in the glove box! To verify it's gone bad, try to start the truck. If it doesnt start, leave the key in the "run" position and lift the lever at the end of the shutoff solenoid as high as possible. If the relay was bad, the sol. will stay up, and you can start the truck as normal.
-Starter contacts burn up & you just get a click, but no start. LarryB's makes oversized contacts to solve the problem and save over $200(most people think the starter itself is bad). Most likely the starter will be fine & just the contacts get burned up. It took me about an hour to do mine.
-fuel strainer screen, next to the lift pump & primer pump. It should be cleaned of sediment & goo that accumulate in it yearly.
-injectors, you know where they go. The best bang for the buck goes to the 370, named after the marine version of the 6BT rated at 370hp. There's Extrude Honed verions for even more power, and EDM's in case you want more power, lower smoke & EGT's.
-Ratings: 94-95 auto=160hp, 94-95 manual=175hp, 96-98 auto=180hp, 96-98 manual=215hp, 96-98 manual (CA equipped)=180hp.
my daily driver:67 F100, 300 4V, cammed, 4 spd.
or, 08 Subaloser Forester, 2" lift.
work rigs: 94 IH 4900, DT466(originally 230hp), #0 fuel plate, tighter gov springs, 22* timing
or, 06 IH 7400, DT466E, 300hp
My Low Buck fuel rate site: