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Your air leak in the fuel line is going to be from the feed to the fuel pump to the tank. Seeing the recent work it is probably the feed fitting in the fuel pump. Either the fitting was installed without thread sealant or was overtightened and cracked the housing. Or there is a leak in the fuel line (won’t leak out fuel only will pull in air). Do you have rubber fuel lines? If yes replace them.
 

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Discussion Starter #102
Well I spent a good deal of time this weekend tuning the AFC. I shaved the inside of the top, I adjusted the star wheel, I tested the difference between the heavy and light pin spring for drive ability, I backed out the fuel pin to the point that one more 1/2 turn and I get fuel leaking out the fuel pin. I also pulled the idle screw that I swear was some engineers idea of a sick joke and put a nut on the forward end of it so now idle adjustment is just a 10 mm wrench and easy.

Results:
Shaving the inside of the AFC top so the guide pin sits higher resulted in a dead spot down low until there was some kind of boost to push the guide pin down and put the fuel pin on the ramp instead of the little spot below the ramp. While I am sure a talented TIG welder could put some of what I shaved off, the smoke screw does just as well. So no harm no foul there.

Lock tight a nut on the forward end of the idle screw will save your sanity when trying to adjust your idle.

Since I had the AFC top off a few times I tested the difference between the OEM and heavy AFC spring. Neither really affected low end smoke more than the other, but the OEM spring definitely gives a more responsive driving experience.

The only thing that really had an effect on smoke was the fuel screw. backing it out 1/2 turn at a time, You could see the difference in smoke output. I would still like to back it out some more, but another 1/2 turn and it starts leaking fuel right out the fuel screw.

Conclusions thus far: When the engine was stock adding things like an extended fuel screw, turning said screw into almost runaway, bumping the pump timing 3/16 inchs and a timing spacer made big differences in power. But now that I have 5x12 injectors and the Hamilton cam complimenting the HE351CW turbo,I find that I am backing things down to OEM. Pump is at stock timing, timing spacer is gone, and I have backed out the fuel screw as far as I can and I still have as much if not more power than pre- injectors/cam ie 30-33 PSI boost with the torque converter holding at 2200 RPM. Quite frankly I might get a stock fuel screw to put back in and see if I can get rid of the last of the smoke and keep the power.

I still have lots of other things to chase like the air leak in the fuel system. A fuel heater delete nipple and new rubber fuel hoses are next on the list for that. Might make a boost leak test kit just to check that aspect. Engine bay wiring clean up is on my list of things to do.
 
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