Thanks for all the great suggestions guys!

Pretty sure nobody (other than a Dodge dealer mechanic) has ever been in the AFC. All the stock caps were still on the pump screws and the guy that owned it was 83yo.

I did have some trouble keeping the full fuel scew at it's "factory" setting when I removed it and took the collar off. I was very careful and marked the screw and jam nut with a sharpie. Made sure not to spin it in the nut and then put some electrical tape on the nut and screw to keep the setting as I put it back in. Thought I had it about 1/4 more of a turn than the 3/4 I started with and went to start the truck, but it wouldn't even idle. I knew the screw wasn't far enough in because it idled fine before, so I gave it a 1/2 turn at a time until it was back to the "factory" setting (at least it felt like it by driving it). Then I gave it another 1.5 turns and it feels like a different truck. I'm still not sure how it ended up being over a full turn out from where I started, but oh well it's where it should be now!

I'm determined to get that AFC open today.

 

Oh...my...gosh!!!

Adjusted the starwheel 1/4 of a turn and rotated the fuel pin 90* and I can't even believe the difference! Boost went from 19psi max to 24psi max and the power is incredible. I can't thank you guys enough!

I wasn't expecting such a huge increase in boost and power from just those two adjustments. It seems my EGT's are right about the same too. Anyone who actually understands how the AFC works and would like to explain what those adjustments did, that would be great to know.

Also, the top of the diaphram had a little corrosion and underneath was kinda gunked-up. I cleaned it out as best I could, but is that normal? Will that gunk get in the fuel system or cause any damage?

 

Yep, that about sums it up. Just wait until you get farther down the slope!

 

The change you felt was from turning the fuel pin. Pull it dack out and eyeball it until you figure out which side is the deep side. Put that side towards the front. The fuel pin allows the governor arm to travel further and add more fuel when the turbo is making boost.

The star wheel is not a real sensitive adjustment. You have to do a couple turns at a time to really notice it. The starwheel controls how much boost is needed before the fuel pin will move and allow extra fuel. The smoke screw up top sets the preload, which determines how much fuel the pump will give with no boost.

The gunk on the bottom and corrosion on top is pretty normal. Clean off the gunk and put a thin coat of grease on the pin, and brush the crud off the top.

 

Thanks Dave! It's nice to know what's actually going on in there when I make changes.

It's running so great now I am kind of afraid to touch it. Can I really expect much more power since I"m pusing 24psi already and have nice cool EGT's? I would rather have cooler EGT's (for towing) and a little less power if need be.

After looking at how aggresive the Bully Dog pin is, it seems turning the stock pin to it's deepest setting would still be fairly mild compared to that aftermarket pin. Is this true? Do you think rotating my stock pin to it's deepest setting will raise EGT's very much while towing? What about replacing it with the aftermarket pin (EGT-wise)?

Also, would cranking down the starwheel some more really make a considerable difference?

Sorry for all the noob questions. I promise I will pass this knowledge on to other DTR members and 1st Gen owners when they have the same questions.

 

How much more power you will get depends on where it was originally. They aren't all set in the same spot, these pumps have wild variations in setup from the factory.

More fuel will raise the EGT, no way around that. How cool is it running now? There's nothing wrong with holding 1200 degrees towing.

Cranking down the starwheel will make the fuel come on sooner, making the turbo spool quicker but adding smoke at the bottom end. That's a setting you will have to fine-tune with your butt dyno and your passenger side mirror.

 

jrussell, have you towed with your truck after turning up the fuel? How are the egt's? I am in the same boat and plan on doing some mods but my truck is for towing so I dont want to go too far. THANKS

 

Wanna: It's running as high as 1250* while unloaded on the highway (floored going up a pretty good grade). I only have considerable smoke at the bottom end just before the turbo spools up. The starwheel is down a full turn and I backed the smoke screw off 1 turn (so it's only in 1 turn from stock now). I will definitely be doing the gov spring soon and am thinking about a fuel pin too. I'm just wandering if the EGT's under load will be a problem after adding a fuel pin? I don't mind keeping my foot off the floor while towing and an eye on the pyro, but having to go much slower up grades or even pulling over because of the fuel pin is not my style.

440forPOWER: I haven't towed a full load with it yet. Just the empty trailer which is about 1200-1400lbs. Of course, couldn't even feel that at all.

 

You will be able to control EGT with your right foot. The pump doesn't add fuel you didn't ask for.

 

Finally got my rockcrawler loaded up on the trailer and took it for spin on the highway. Total trailer weight is about 5k and couldn't even feel it back there. Plenty of power and with the cool outside temps (~60*) I could not get the EGT's above 1200*!

 

Thanks jrussell good to hear. Just curious though, what were your egt's when cruising 65-70 on somewhat level ground? Thanks again, I think I'll have to find that fuel cone

 

One last thing to watch out for when turning the power screw up. Keep an eye on the rpm's, if you give it the throttle and then let up but the rpm's stay up there for a time before coming back down. You might be close to a run-away motor. Only way to stop run-away motor is to stop the airflow going into the turbo by putting a board or something over the opening (watch fingers). If that is happening, then you would need to back off the screw a tad till the motor is happy again.

So, please. Play with that screw as it DOES make a big difference but there is a limit on how far that screw can be turned without making the motor go insane.

 

Thanks for the info.

So pulling the fuel solenoid wire won't shut down the motor when in a run-away state? Why is that?

 

Usually the pump will eat the tip of the shutoff plunger.

 

Did some more towing today, mostly on flat ground with small hills. Cruising in OD at 70mph my EGT's were 800-1000 (with an average on flat ground of around 875-900). Floored it on a couple of hills and max EGT's stayed under 1200* (~90* outside temp).

I did notice my coolant temps were warmer than normal with the load above 60mph (in 3rd and OD). The factory gauge was reading just above 1/2 (needle pointing straight down) all the way up to the 2nd mark a couple of times. It ran steady near the second mark when I tried to go 70mph in 3rd. The radiator has just been flushed and a new thermostat put it (but not a cummins ). This T-stat seems a little goofy. The first time the truck heats up the temps go almost to that 2nd mark, then come rushing down to way below the first mark and run normal after that. Should I just bite the bullet and put a Cummins T-stat in instead?

Also, should I be able to run 70mph in 3rd on pretty flat ground and keep decent coolant temps?

EDIT: FWIW, my tranny gauge didn't reach 180* the whole time and that's mounted in the stock hot-line port.