Engine/Transmission (1994 - 1998) I feel like an idiot...

[BigEasy]

Now that I have my first Cummins, I realize how much I DON'T know about them. My truck didn't come with an owner's manual, but I want much more info than it can provide anyway.



I want to do the simplest of all mods, turning up the pump, and I don't even know where to look on the pump for the screw...



I'm getting a very new perspective here... and I'm sure it's a good thing. I've known gassers inside and out since I was old enough to bust my knuckles with dad (I was changing oil at 5) and eventually building up several 800hp+ small block chevys, but I have no clue on some of the VERY basic knowledge on these trucks. Now I guess I have a better understanding of the people (whom I've laughed at alot) who can't change their own oil...



I guess what I need is a service manual... where can a guy get one?

 

[tp0d]

Well, I`m not sure about where else to get one new or used, but Ebay has one for a price...



http://cgi.ebay.com/ebaymotors/SERV...34218QQitemZ8002826870QQrdZ1QQsspagenameZWDVW



I got mine thru here, got lucky. Theres gotta be somewhere else you can find one, its just a matter of finding the correct year.



I also have to add I`ve learned more about my truck here than in any book. Particularlly about tweaking the pump (there is no screw on yours, only a 1st gen i think)



So, do a lotta reading, some searching, and you`ll prolly find what you're lookin for... The service manual does come in handy sometimes tho. .



-j

 

[Forrest]

Here's a site with some good stuff:



http://www.dodgeram.org/

 

[JoshPeters]

No no no... Your not an idiot... . MANY people still dont' understand the basics of a diesel engine. Even people here.



I'm off to work now, but when I get home for lunch I'll type some of the basics up for ya!



Honestly I would have been in the same boat a few years ago, but I took Diesel in Tech school.



Josh

 

[BigEasy]

Here's a site with some good stuff:



http://www.dodgeram.org/

That's exactly the kind of stuff I was looking for! You DA MAN!!!

 

[surfbeetle]

Big Easy, go to the TST website and look at the throttle plates. For around $250, you can dramatically improve your truck's power. This is one of the easiest ways to "turn up" your injection pump.

 

[JoshPeters]

Alrighty some of the basics:



As you probably noticed, our engines as well as all diesel engines do not have throttle plates. Unlike gas engines that are controlled by airflow our engines are controlled by fuel. This being the case we can hold, lets say 2000rpm and have FULL fueling, or very very little. This is why our engines are more fuel efficient. They will only use as much fuel as they need to hold that Rpm. This happens through the Governor inside the injection pump. The Governor is spinning and has weights and springs that at a set tension will only move so far at said RPM. If the Set RPM starts to drop, the springs and weights start to pull in, when they pull in, they move the Rack inside the injection pump.



The Plungers and Barrels... . the Barrels as an assembly are the "rack. " Immagine an engine pistons moving up and down the cylinder is like a 2 cycle. Outside that is a rotating cylinder and the walls are tapered like an upside down triangle from the top corner to lets say half way down the wall. When the piston moves down the Fill port (2 cycle cylinder wall opening) is at lets say, the bottom part of the triangle allowing a full fill time, this would be WOT. At the top you can only get a little fuel in before the opening closes. This is idle. To shut down, the fill port is put to the cylinder part of the triangled cylinder. No fuel is allowed. (this is the best way I can explain it, I know there is MUCH more to it, but basically I hope this mental picture helps)



Now, how they control the fueling is slightly more complicated. The Rack travel is limited by, the AFC, the Governor, and the Fuel plate.



You STAND on it, inside the pump the Governor arm moves up to ride on the fuel plate, but it's limited by the AFC. The AFC has a diaphram that only moves when there is a boost signal. So when you initially stand on it and there is no boost you don't actually have WOT. When the boost signal pushes the diaphram forward, you get more fueling. The Governor arm then rides up on the Fuel plate allowing only "so much" fuel depending on the plate and RPM. If you have a 10 plate the profile will allow a smller ammount of fueling at first (low RPM) then much much more (high RPM). A 0 plate is everything, right now all the time!



To throw a little wrench in the deal is the Governor assembly. It's spinning away inside the pump at low speeds the Governor arm is at the low end of the plate, as RPMS increase it slides up the plate and will allow only the ammount of fuel that the plate designates.



Well I have to head back to work... . I'll try to post again later with more. If you read this and have questions... or comments... . add away or ask away!



Josh

 

[biggy238]

Man, I typed like a whole page and it dissappeared.



Anyway.



Geno's Garage is a good place for a Factory Service Manual. . They have Cd's and Book versions.



Before you mess with the pump: More Fuel and LESS Air means more EGT. . this works all the time. . from stock to highly modified engines.



More fuel means Higher Exhaust Gas Temperature. Higher EGT CAN and WILL damage the head and DESTROY the turbine in your turbo if not monitored.

You need an EGT gauge and a Boost gauge. Geno's also sells these, some in kit form.

Most gauge pods accept 3 gauges. . My suggestion is the 3rd be a transmission temp.

When you get the EGT gauge, install the pyro sensor BEFORE THE TURBO in the ehxaust manifold.





Now. . to the fuel letting.



Beside the brake master cylinder, just in front of the fuel filter, and directly beneath the oil dipstick tube and your #5 an#6 injector supply lines is the AFC. AFC is Aneroid (meaning the absense of air) Fuel Control. It has a line from the outlet of the turbo running to it. It senses boost pressure from the turbo and limits the amount of fuel that can be added before the turbo spools and build pressure. It has a plug in the to of it. Removing that plug allows access to the "starwheel".

The starwheel tensions a spring that controls how much pressure it takes from the turbo to move a lever out of the way of the governor arm (gov arm controls fuel supply) In this way, it limits the fuel before spoolup. Turning the wheel toward the engine adds fuel before spoolup. This makes for quicker acceloration and quicker spool time. This also creates added heat, because you are adding fuel when there is no added air supply.



The cap that IS the afc can be removed be taking out 3 screws and one tamper screw, which must be sheered off.

Once there, you will see the "Cam Plate" the AFC lever passes through a slot in the cam plate.

Moving the cam plate toward the front of the engine adds fuel at boost (in all driving conditions) This plate can also be swapped for a plate with a different contour or profile cut into it. This contour is what controls the Fuel Curve that the engine runs on. That covers basic fuel addage at the pump.

The governor springs control are a centrifugal device that controls rpm. The engine will fall on its face at 2200rpm. . it will rev past that, but without fueling. These can be replaced with 3000rpm springs or 4000 rpm springs (3kgsk and 4kgsk) 4k's require exhaust valve springs to be added to prevent valve float.



Lastly, you will find that your stock auto transmission will only hold about 300hp. The torque converter is insufficient to hold the torque that these engines make.



You will want to be very conservative about the power you add until you can afford a transmission upgrade that can hold the power.







Hope this is what you want to know. Ask ans search around and you can get the nitty gritty details. . mine is just an overview of adding fuel and how to go about it.

 

[BigEasy]

OK... thanks guys. I do know a lot of the basics of diesels, and which parts(by name) do what, but looking under the hood and pointing to each is a different story. I'm gaining more confidence quickly, too... I wasn't quite as clueless as I thought.



I started looking around, and this truck has been played with a bit... the silencer ring was already gone when I went to remove it and the tamper-seal bolt on the AFC is gone, replaced I should say.



I thought this old boy ran pretty good... now the fun will be figuring out what all has been done... I know the TC is still a stocker, it's as sloppy as a 60 year old hooker!



Do most replacement VBs have a logo on them or anything? The transmission seems to shift very well, just the TC slop that I mentioned above.