New Member with a new truck and a question

[Smoke4Broke]

Hey Everyone.
This is my first post so here it goes. I purchased a 92 D250 with a getrag a few months back. It is all stock so far. I have gone through the truck and changed all the fluids/filters and filled up the transmission an extra quart. I've been driving as much as I can and the truck has been running great so far. Recently I rotated the fuel pin 90 degrees and turned the star wheel a turn and a half just to see how it would go. Nothing too crazy. It worked great and the result was better than expected. That was a week ago and now the truck has not been running the same. Before the truck would rev up nice and smooth as the boost rose and speed increased. Now it seams the engine does not rev as smooth and the the power is not their like before. I'm trying hard to explain this as best i can. The engine seams to be reving higher with less power. What could this be? A lack of boost? There is only a little smoke with hard acceleration so I dont think it is. I check the seals around the banjo bolt and the afc itself for leaks. I'm not sure where to start. Could it be the fuel pressure? The only thing that has been done since I turned the pin was a fill up and added some fuel treatment.
Any ideas would be greatly appreciated.
I dont know if you guys are like me, but when something is broken I cant stand not getting it fixed asap. Sorry for the long post
-Thanks again. Cant wait to learn as much as I can here.

[PToombs]

Do you have guages yet? They should be at the top of your list, especially if you are going to tow or turn it up any more. They are a great tool for figuring out what's wrong.
That said, try changing the fuel filter and see if that helps.

[Smoke4Broke]

No gauges yet. Definitely planning on getting some. I couldnt resist the urge to turn the pin that I've been reading so much about. I'm not about to go crazy with the mods yet, being a unemployed college grad and all. I guess I'll put the pump back to stock to see if it does the same. I changed the fuel filter last week. Any other idea?

[PToombs]

Maybe the lift pump is getting bad. Hard to say with out a guage. Geno's Garage has a tapped banjo fitting for $7 that you put in the out flow line on the filter head, and can put a guage in. Any guage will work to see how much you have. Should be no less than 3 psi at WOT.
Are you sure you put the cone to the deep setting? Or did you just turn it 90*? Look at it, the cone is offset one way. Put the deep side towards the front of the truck.
Maybe double check the little line that goes from the head to the AFC housing on the pump. They are known to break and that loss of boost to the pump will cut the power fast too.
Good luck!

[Smoke4Broke]

I was thinking the lift pump too. I havent had the truck long so I'm bound to find bugs in it as I go along. I might as well just throw one on as an insurance measure. The truck still starts normally so I dont know. I also was looking at the the line coming from the manifold. Mine has a little piece of thin metal wrapped loosely around it. It's about an inch long. Is that supposed to be there? As far as the pin goes I'm pretty sure I got the pin right. I doubled checked it today. I have it turned 90 clockwise. Whats weird about it is that it was working great in the beginning and now I'm having problems. Makes me think it fuel related. No smoke too is a hint I think .

[dpuckett]

If it's stock, it wont smoke. Even a hopped up engine wont smoke much, if all is tuned well.
Check the pot metal line going from the intake to the top of the injector pump. It will break if you fart in its general direction.
Check your lift pump output. If you change it, dont mess with the stock type pump- upgrade to a piston lift pump (low pressure, not 2ndGen).
Have you changed the fuel filter?
Where did the fuel come from? most people have better luck with places that sell a large volume daily- truck stops are a good bet.

Dan

[Smoke4Broke]

Thanks Dan

You're right the line from the manifold looks very delicate. Whats the best way to see if its broken or not? I dont want to mess it up any more than it might be. And if it is broken whats the best way to fix/replace it?
I've also heard to upgrade to a piston lift pump too. What would be the best one to get? One thats not too pricey as I dont have too much funds at the moment.
The fuel filter has been changed not ling ago, say 2 weeks
The fuel was bought at a stations with the larger area for trucks so I'm sure they go through their diesel quiclky

I appreciate any help
Thanks again

-Mike

[Jfriedlin]

All it takes is one tank of bad fuel to stop up a filter and make them run like crap. I'd start there and definitely get some gauges as soon as financially possible. You can tell alot by boost pressure and EGT's

[dpuckett]

I replaced mine several years ago with a 1/8NPT-1/8OD airline adaptor from the head; a 1/8OD airline union off the pump, and about 6" of line in the middle. Allows full AFC function, and even if you get the parts at NAPA, you are still <$10, vs $30 at Cummins or $50+ at Dodge.

Dan

[RumbleFish]

I replaced mine several years ago with a 1/8NPT-1/8OD airline adaptor from the head; a 1/8OD airline union off the pump, and about 6" of line in the middle.

and i replaced the almost smashed shut 1/8" fittings and line with 1/4" air brake line and it made a HUGE difference. i can keep up with traffic now!

[dpuckett]

Jeff- what did you do for the pump end? Drill and tap, or....?

[RumbleFish]

tim worline stopped by on his return trip from sop and saw it, and then showed me his. i drilled and tapped the pump top, and found the appropriate fitting for the manifold. night and day difference. one of the 1/8" compression fittings was so tight it was nearly crimping the line shut, which is probably why i noticed such an improvement.