Engine/Transmission (1994 - 1998) Star wheel

[DickersonD]

Buy clicks do you mean complete 360 revolutions?

 

[Devan Manis]

Don't waste your money on an aftermarket plate just grind your stock one, if you do a search there is a ton of info on grinding your stock plate into many different profiles. You will need a new clutch at the point of grinding your stock plate. but for now just slide your stock plate.



did you see this page on the 3D web site? these will probably clear up alot of your questions. http://www.dodgedieseldatabase.com/p-pump_cut_away.htm

 

[DieselMinded]

here you can see the fuel plate



#ad




DM

 

[biggy238]

That is the Sweetest pic I have seen on here for tech.



Dickerson.



Get gauges. I agree that your truck can handle the EGT's with the plate forward. The most mine ever see's is 1050*.



The gauges are one of the best diagnostic tools you will invest in. Don't cut your plate until you have gauges or you will run too hot.



In the pic, The AFC foot is toward the rear, blocking the gov arm from contacting the plate. Thats why the AFC only affects pre boost. When boost is achieved, the arm moves and the gov arm rides on the plate from then on out. The Gov arm is only there pre-boost.

 

[DickersonD]

So in this cutaway pic. is the fuel plate pushed forward or in the stock location. Do you just loosen the screwson the plate and push it towards the front of the engine?

 

[Devan Manis]

do you see the enlongated holes in the plate? you loosen the bolts that go down through there they aren't in the pic because they would get in the way, slide the plate towards the front of the engine. you can see the two bolts on the top of the plate in this picture.

 

[Willys]

Buy clicks do you mean complete 360 revolutions?

I mean clicks, like the degrees on a compass. My 8 clicks would be less than a turn, probably 1/3 or so of a turn judging by the cutaway pic(thanks DieselMinded). BUT, do not listen to me, this is the only thing I've adjusted on the pump, for curiosity's sake. I don't have any real data showing anything changed, just a feeling that it picks up speed a little faster on a hill. No big black clouds of smoke here either. I'm not a racer, or heavy hauler, just trying to get this pile of iron to go up a small hill.



biggy238, what do you mean by 'boost is achieved'? Is there a measurable point at which the AFC foot should move, in terms of boost pressure? I'm starting to understand how the AFC works in relation to the plate. What is the mechanism that cause the rod/foot piece move, a diaphram? By adjusting the star wheel toward the engine, we're basically allowing the governor arm to come closer to the plate, increasing low end fueling. Is there an optimal generic setting for this, or is it a trial and error, see how black you can make the highway, and then back off a little sort of thing? Is this adjustment subject to major changes with only a minor adjustment of the wheel(8 clicks? ), like sliding a plate 1/16" would make for a noticeable change in power?(and egt )



With the AFC gutted, the governor arm would ride on the plate all the time. The low speed fueling would be only metered by the profile of the plate itself. I'd figure this would make for a good bit of smoke if you don't have enough air. :-laf



Am I right so far, or am I just making an idiot of myself? :-laf



EDIT: I notice what looks like a red diaphram in the pics here

If something were to happen to this diaphram(rot?), would it create a low power condition? No black smoke, little power at full throttle?

 

[SDrake]

Make that two of us, Willys, I am sure there are more potential idiots out there. I have been slowly putting our pump together in my mind from the pics and discussions.



I have a related question. Why is the fuel plate having steps and not a smooth transition? I can't see in the pics how the finger on the govenor arm can move up or down in relation to RPM while at the time it moves toward the plate, but I assume it has to or the profile on the plate does nothing. But if it does as I assume it does why the steps. Why not a smooth transition up the speed curve. It looks like at one speed you are on the top of the step and then at a slightly higher speed you are suddenly getting more fuel. Doesn't make any sense to me.



So maybe I get the honors of being the idiot But at long last maybe I will understand.

 

[Forrest Nearing]

I believe that big step on the stock plate is to reduce torque at WOT shift point to keep the stock automatic transmission alive

 

[SDrake]

Thanks. That explains what I was attributing to turbo kick at rpms slightly higher than peek RPM at upshift. My truck would do about 95 MPH which told me it had a lot of power somewhere but at 65 it didn't feel like it had enough kick to get to 95. But towing at 65 the power was disappointing. The #10 plate has changed that somewhat. The 10 also has a step but it is different. I wish I had traced it out on a piece of paper so I could compare it to the stock plate. This would have helped me relate a little better to the before and after power. But at least the mystry is not so dark.

 

[biggy238]

Willy's you are dead on it. The Diaphram inside the AFC (Aneroid Fuel Contorl) is directly connected to the intake manifold via a small tube. And yes, if it were to be damaged it would lead to a low power condition after boost came up somewhat. You would have enough air to burn the fuel, but no supplemental fuel because the plate would not be in play. This has been the subject of several "low Power" posts lately.



The starwheel adjusts tension on the whole assembly. . I must admit I haven't studied directly how the spring affects it because I couldn't see it until now, but, as we know, turning it provides more "pre boost" fuel. This accellorates the truck more quickly and also provides extra fuel to spool the turbo, which in turn moves the AFC foot out of the path of the governor arm more quickly.

This does raise the EGT but unless a problem occurs on the turbo's part, it should be within a safe level.



Moving the AFC housing moves the AFC foot closer to the plate profile, which means the AFC foot travels a lesser distance before the governor arm contacts the plate.

One other note for future reference, In some posts, others have discussed the governor arm Going "under" the fuel plate when it rotates forward. This is caused by the fuel plate being too far forward in the pump housing. The governor arm can be adjusted to contact a plate that is this far forward, but I don't remember the details of the adjustment as I read them.



Unfotuneatley I don't have a better understanding of the rest of the pump.

I hope this helps thicken the Mud. Feel free to ask more. . surely someone has an answer.



Kyle B

 

[biggy238]

Sdrake. . Sorry I missed your post. I dunno how it works, But somehow the Governor itself allows the arm to follow that profile. . I believe that the plate istself is cut like it is to produce the nearly flate torque curve these engines have from the factory.



The governor (if you don't already have a GSK) is the drum at the bottom of the pump in that cut away picture. It rotates on a front to rear axis and can be accessed by the gold plug in that picture. I haven't messed with mine. Like you all said, pictures work wonders when you try to piece it together from text.

 

[Willys]

SDrake, we should start the cummins idiot club.



biggy238, Thanks for affirming and clarifying that. Have you adjusted your star wheel or slid the AFC, and adjusted the governor to match your 'slid stock plate'? With those 35's, are you able to accelerate easily(no load) from the 50-55 mph range? I don't think I'd be comfortable with that big of tires, 3. 54's, and my current power setup! (in my '96) I like the 4. 10's on the '95 I just bought, but I wouldn't want to run long distances unloaded unless I had 35's... .

 

[biggy238]

From 55-75 it accellorates nicely. . The peak of the torque curve happens at about 1700 rpm and is already strong at 1500.



I'm not sure how far forward my plate is comparison to how far it can be taken. I have about 3/32" past stock right now.

I live in the mountains in KY and have several 6% grades that run for 1 mile or more and sliding the plate made the truck alot more driveable and didn't affect my mileage at all- considering I had 17mpg with 33's and no power mods- and now 35's with more power.

I have slid my AFC forward and turned the starwheel, only about 15 clicks on the starwheel though. If I stab the throttle from a stop I can get about a 6 foot ploomb and then it clears. At night, from an intersection, The truck does smoke/haze enough to dim headlights behind me.

I have learned how to make it smoke furious amounts with the automatic based on the lockup of the TC and my RPM. If the TC just has locked, I can lug it and smoke furiously for about 4 seconds. I also have one passing lane that every time I go to pass someone, the truck smokes. It's a long down hill and then a sharp up hill and the truck goes from unlocked and coasting into locked and no boost almost instantly. I've made people gasp on that one before.



I don't like that fact that overdrive puts the truck at under 1500rpm at speeds below 60mph, but I usually run about 70. I use OD lockout for speeds under 60 to get into lockup sooner. My transmission and TC are weak. It takes me a while to get to speed, but after that the performance makes me smile.



Once it hits 3rd gear lockup I can out run ALOT of things up until it governors at 2100rpm.

I have plans to cure all of this but I don't have the money.

If you are in doubt about toying with the factory plate, go ahead and slide it. I have left mine at what I see as Adequate because fuel is so high.

 

[Forrest Nearing]

if you drive it the same, fuel consumption will probably go down if you slide the plate all the way forward...

 

[Willys]

Forrest, its a power on tap kinda thing, Not used most of the time...



Biggy238, thats what I wanted to hear!



Now if only I can get Santa to bring me two sets of gauges for Christmas.

 

[biggy238]

Forrest, yeah that's something I have noticed... A plate less than full forward seems to be truck dependant on whether mileage will drop.

Full forward though, everyone seems to report a drop.



Willys, Now, keep in mind it's not gonna turn it into a drag truck. . But it made my truck... Fun. All but the newer four cylinders I can outrun... unless they have work... Alot of the 6 cylinder vehicles I can pull on. . I had my rear handed to me by a 4. 0 cherokee one night though. . I got to laughing so hard it didn't really matter though.

It's a toss up on how the truck will rank against others. I know from a kickdown of about 40mph up to 60 I was pulling on a superduty before he let out to catch a stoplight/turnlight. Before I slid my plate, my truck would actually shift going up hill because I had the pedal so far down the TPS was shifting the truck. Now, it has enough juice to pull up hills to almost 90mph. (run out of hill at 85 usually)

Don't be affraid to run the engine hard. In stock trim, with fluids in it, the motor is indestructible. It will governor out before it runs hard enough to hurt itself, and without a plate, it won't run hot enough to hurt itself. . Thats not to say that the rest of the truck can handle it. I need a transmission so bad I can taste it, but i'm babying this one for now.

 

[DickersonD]

Wow,thats alot of great info guys. Its nice to know that not everyone here is a p-pump rocket scientist. For those of you who have slid your afc and fuel plate exactly how did you do it. I'm looking for a step by step,kinda of like TST's KDP tab instructions, if it exists.

 

[biggy238]

What I have told is what I have learned on here in about the last year, and then going out to the truck and tinkering.



DickersonD



Step By Step:

Tools Needed: All Mandatory!

Hammer

Flat Head Scredriver

Sharp, small chisel or sharpened flat head screwdriver

Wobble Metric Allen Wrenches

Metric Sockets and Wrenches

Pencil Magnet

Favorite beverage and inspirational music.



Looking at the engine from the drivers side fender, you will see the injection pump. Behind the rearmost two injection lines, and directly below the oil dipstick, just beind the intake horn (big grey piece in the middle of everything) -

On the rear of the injection pump, Is the AFC itself. It has one large plug in the center of it. This will require an allen wrench to remove.

This plug can be removed without removing anything else. This plug allows access to the "Starwheel". The posts earlier describe everything about it.



The metal piece that is the AFC is held onto the pump by 3 slot head machine bolts and one "tamper proof" screw. This screw, from your viewpoint, will be on the top, lefthand corner of the AFC (under the injection lines) This screw will have to have the head sheered off to gain access to the fuel plate. This can be done carefully with a sharp screwdriver and hammer.



Because I am a large individual, I removed the intake horn to do my plate adjustment.

It has four (12mm I think) bolts holding it to the head, one more toward the front of the engine, and one holding the oil dipstick tube to the intake horn.

Loosen the clamp on the intercooler boot at the intake horn.

Remove the 6 bolts from the intake, taking care to note where they were taken from.

Gently pry loose the intake horn. DO NOT DAMAGE OR DISCARD THE GASKET BELOW IT. It is reusable. The Intercooler boot should still be attached at the time you "break loose" the intake horn.

When The intake is freed, Work the horn out of the intercooler boot. Take a shop towel and insert into the intercooler tube. This is very important as there is nothing between that tube and your engine that can catch debris if it were to be inside the tubing when the engine starts. Also lay a rag over the grid heaters (you will know them when you see them) As this is the intake manifold and you don't want something in there either.



With that out of the way, Remove the AFC housing from the pump. The Fuel Shutoff Solenoid is held to the pump by the lower two screws and one at the rear of the pump, making the two in the AFC longer than the remaining top screw and tamper proof screw. Take out the three screws and pull the solenoid slightly toward the fender to clear the AFC.



Take care not to damage the small hose connected to the AFC. Set it safely to the side or rear.



The AFC will uncover the top of the Fuel plate. The fuel plate is held in place with another two screws. Take a Scribe, nail, or sharp object and scribe a line on the injection pump housing so that you know where "stock postition" is. Preferably mark the pump on the Cab side of the plate so that you can visualize how far you have slid the plate.



Also, at this time, Remove what's left of the tamper proof screw. It will be sticking out of the pump body. Place a shop towel in the slot on the fuel plate where the AFC passed through so that you cannot drop the stud into the pump. A pair of needle nose visegrips will make removing this stud perfection.



DO NOT REMOVE THE PLATE SCREWS if you are sliding the factory plate. Merely loosen then. Slide the plate. Retighten the two screws. If you install an aftermarket plate, obviously the screws will have to come out.



Check to make sure that the gasket on the underside of the AFC is intact and clean. It is rubber and reusable. Place the AFC back onto the pump.



Here's the part I will need help with. You will want to install Metric size 4mmX16mm ALLEN HEAD screws (i think that's the size, you will need to double check this Joe-G knows) in the top two holes and metric 4mmX24mm in the bottom two holes. The longer screws are to accomodate the Fuel Shutoff Solenoid. Move it back into position.



You will NEED ONE FLAT WASHER AND ONE LOCK WASHER for each screw. Take a pencil magnet and stick the two washers and the screw together as they will go into the AFC (Flat washer on AFC, Then Lock washer) Use the magnet to put them into the pump and the wrench to tighten them.



THIS IS WHERE YOU WILL NEED A WOBBLE SET OF METRIC ALLEN WRENCHES. The top left screw is under the injection Lines. By using Allen head bolts, you have allowed yourself to remove the AFC and adjust the plate without having to remove the injection lines. The Wobble wrenches can rock over far enough to clear the lines.



Tighten the AFC and fuel cutoff solenoid down.

Re-insert the Intake horn into the intercooler boot, do not tighten clamp. Position intake horn over the grid heaters and gasket. Insert all four of these bolts and the 5 out front FINGER TIGHT. you will need to do this to allow all five bolts the chance to thread. Tighten all five of these bolts down to factory torque (i have no idea guys).

Re-attach the distick to the intake horn. Attach the intercooler boot clamp at this point.



DOUBLE CHECK ALL OF YOUR WORK AND ACCOUNT FOR ALL PARTS.



When I did mine, I dropped a screw. Because I was curious, I pulled out the plate, leaving a hole in the top of the pump. I didn't see where the screw went and paniced for two days. I'm trying to save you all from that. This is DEFINATELY the idiot P Pump Lesson.

Bookmark this thread.

 

[Forrest Nearing]

I say fuel CONSUMPTION should drop...



w/ the same timing and injectors, as long as you drive it like a sane person, mileage usually goes UP as you allow it to use more fuel and make more boost at a given load/rpm