Engine/Transmission (1994 - 1998) asking alot

[Berrigan]

I know this is asking alot but could some pump savy member explain the sequence of operation of the pump. I know the lift pump supplies low pressure filtered fuel to the inlet of the injector pump. And I know the injector pump distributes a high pressure fuel charge to the cylinders at the correct time. What I was wondering was if someone could explain the operation of the afc, the plate, ( what pushes on what when why and how), the governor and the like. Kinda like (the hip bones connected to the thigh bone and the thigh bones connected to the knee bone)



The reason for this post is to understand more than just put in a #11 plate and you will go faster. Like is the #11 ground deeper (less metal) And does that let the fueling arm? run further forward to allow more fuel. Is moving the plate forward doing the same thing as cutting a small amount more off the plate in the same contour?



TST says I must change my #11 for a #10 in order to take advantage of a 3kgsk. They say the #11 wont fuel much at 3000 rpm. Does that mean that the contour of the cut on a #11 shuts fuel flow down at 3k? Is the contour of the cut like a coded sculpture that the arm follows that controls fueling. Could I grind another 1/16 inch off of the top 1/2 inch of the plate to increase high rpm fueling? Does the arm start at the bottom of the plate at low rpm and move up as rpms increase?



And the afc. I know it controls fueling in response to boost and how soon it gets richer but does it have anything to do with total developed hp?





thanks in advance for any feed back. Bill

 

[bighammer]

I think you are on the right track but why mess with grinding it? Doesn't TST exchange plates? Might check with them first.



Moving the plate would be the same as grinding the whole profile. Grinding one part would change fueling in that one area. I think you are right that it rises on the plate with RPM.



Go ahead and blow yours up and let us know what you learn.



BTW: I have a governor schematic and some other diagrams/drawings. PM me if you want them.

 

[esommer2500]

I am also looking for any/all info I can find on this enigma of a pump. I am still young and in the very early procecesses of learning (I have been in to adjust my 3K springs three times now) All I see when I am in/around that pump is springs! I am at about the same spot as Berrigan, but yearn for more info. Is there a publication by Bosch that shows a whole schematic of the entire pump? Or am I dreaming...



Eric

 

[chrleb1]

These pumps are pretty interesting. i have gotten the chance to take one apart and help build one. There is a ton to write about these pumps. Gov. springs... the harder the springs, the less it will defuel in high rpms. Plate and the AFC and the gov. springs control rack travel (amount of fuel). If you want to know more you can PM me and i can share some. But if you really want to know some crazy stuff... . call Piers Diesel. He is really smart. My brother (Reb. B) are always blown away.

 

[Reb.B]

okay, heres a little to keep your mind rollin'

The pump is like a motor. It has barrels and plungers. The plunger is hooked to the cam of the pump and the cam pushes the plunger up and down inside the barrel making fuel pressure. The govenor assembly is on back of the pump. at a certain RPM it pulls back on the govenor arm. The gov arm is hooked to in internal thottle linkage. so the key to getting your pump to perform is to move the internal throttle linkage. the brain of the linkage is the plate. the gov arm slides up the plate. the plate is curved for more fuel in the mid range or whatever u curve the plate. The afc is a throttle stop (just like the plate). The boost from the motor pushes the afc arm out of the way so that the gov arm can hit the plate and go from there.

Okay conclusion. u have an internal throttle and when u push the gas pedal u have three major obsticles to cross over, the afc arm, the plate, and then at a certain rpm the gov pulls on the throttle and reduces fuel. By adding the right size stiffer springs, u are putting more tension on the gov assembly and it takes more rpm to make the gov pull the throttle back. Hope i didn't confuse u more. Hope this helps a little.

 

[Smokin Dodge]

Ive heard of people hollwing out there AFC housing, is there any advantages or disadvantages of this?

 

[Reb.B]

ya u can remove the afc spring, remove the afc arm, or just take everything out and plug the afc boost line going to it. Can u say SMOKE the very second u push the throttle, lol. it will be hard to controll the throttle at low fuel/rpms. it will go from idle to full fueling very fast.

 

[JGK]

Telling alot!

Berrigan,



I had the same questions last winter and posted it on the TDR. Got several answers, and by “pasting” them together mentally, and doing some outside research, I came up with the following understanding. I’m not a mechanic so this is just my take on it based on what I’ve read and done on my truck.



The governor stabilizes the quantity of fuel output by the pump at a given throttle setting. Without it, it would be very difficult to keep a constant RPM at a given throttle setting. The engine may even race away without it. It also adjusts the fuel being delivered at a given throttle setting as the load on the engine changes. So as you start up a hill at a specific throttle setting, and the load on the engine increases, thus slowing the engine, the governor will increase fuel to compensate as best it can. Of course at some point, you have to add more throttle for even more fuel. The governor isn’t perfect. Different governor springs causes it to behave differently. The 2 kits you can get (3K and 4K) just restrict it from defueling at higher revs, thus letting the engine rev higher. Throttle response is much better with these kits, by the way.



The AFC controls fueling in the low rev range before there is much turbo boost. It holds back on fueling until the boost comes up enough to supply the air needed for efficient burning. By backing off the star wheel or sliding the housing forward and thus reducing the AFC’s restriction on low-end fueling, you get more fuel at low boost. Hence, more low-end smoke. But low-end response is better. So adjusting the wheel and moving the housing is the way to balance smoke with response. At about 8 or 10 lbs of boost the “finger” in the AFC is out of the way and no longer has any effect on fueling. It’s all up the plate now.



The plate controls the fueling once the AFC moves out of the way. The profile of the plate controls fueling over the range of RPMs, and, with the governor, will add or reduce fuel at a given RPM based on engine load. As bighammer said, moving the plate forward moves the whole profile while grinding a section just affects fueling in the associated range. I think the pump is very sensitive to small changes in the profile. That is why it is suggested the plate be moved only a few hundredths of an inch at a time. A lot of research went into the plate’s profile for optimum performance. Still, many do a little customization and get good results. Some folks are running with no plate, or a “0” plate, which is essentially just a flat surface. Notice how most plates slant back in the upper part to reduce fueling it higher revs. Without that, you get extreme EGTs at higher revs, which can only be controlled with your foot.



Next is the rocker arm. This is the arm or “finger” that follows the contours of the plate. Piers suggests adjusting where the arm initially contacts the plate when the plate is changed. Doing this adjustment makes the engine respond much better. The arm often hits the plate too low, usually under its “nose” and it takes more throttle and higher revs for the arm to get up over the end of the “nose” and into the power range of the plate. By adjusting the arm to hit just above the tip of the “nose”, the engine performance is much better. You’re right at the point of the power curve of the plate as soon as the AFC gets out of the way.



Finally, I guess, is delivery valves. These I know little about, other than they control the amount of fuel pushed out by the plungers. Bigger valves allow more fuel to go to the injectors. They seem to be more of an issue with the earlier, smaller horse power pumps when bigger injectors are put in. I don’t think they are as important with the 215 hp pump until you get really huge injectors.



Oh, yeah, speaking of injectors, I guess that’s really the final, major component. Big injectors mean greater fuel delivery. However, how far the injector sticks into the cylinder, the number of spray holes, and their angle of spray relative to the axis of the injector are important. That’s why only certain ones are recommended for our application, such as the 370 Diamond Bs available from various sources. Custom made injectors from the performance shops, like the extrude honed ones and so forth, have been designed to work with the Ram CTD.



Sorry for the length of the post, but I wanted to return the favor for those that answered my questions in the past. All you experts please correct me where I’ve gone astray.



-Jay

 

[HoleshotHolset]

Jay: My only question is... . How in the world did you type all that without hitting the inactivity timeout of the vBulletin software?



Great info... . it's good to see that there are still some of us out there that listen and digest... . then divulge the information to those who need it.



Matt

 

[JGK]

Holset,



Computer secret... type it up in Word, use the spell checker, then cut and paste it into the reply.



-Jay

 

[HoleshotHolset]

Ahh, them there speil chekers arent wurth a dern thang... .



Matt

 

[illflem]

Great write-up Jay. If you add how the turbo and wastegate work in conjunction with the pump the whole process will be there.

 

[Berrigan]

Jay,

Thanks for the reply.



Does the plate have a predictable design as to you can tell where on the contour the rpm range is? Another words say the contour is one inch long from bottom to top. Is the first 1/4 inch from the bottom the idle to 1300 range and the next 1/4 inch 1300 to say 1900 and the next 1/4 1900 to maybe 2500 and the next 1/4 2500 to 3000?

What im gettin at is if you wanted to get 4000 rpm out of your motor with a stock plate and you put in a 4kgsk would the plate just fuel the same from 2500 on because the finger would already be at the top of the contour. Or does changing the gov springs like reset the rate at which the finger climbs the contour of the plate.



Thanks again for your help. Bill

 

[JGK]

Berrigan,



I can't answer that. It's beyond me. Perhaps Piers or someone at TST can.



I believe, however, it's not quite that straight forward. For instance, at a given throttle setting and a given load on the engine, the rocker arm will be hitting the plate at a specific point. However, if either of those two change, the rocker will move. So if the load increases, such as going up a hill, the governor will do its thing and the rocker will move to add more fuel. The opposite will occur if you start down a hill.



So I suspect the profile of the plate is designed with this in mind.



But, hey, I'm not a Bosch tech, so I could be all wet!



In general though, I'd bet if you ground a little off where the plate slants back to defuel at higher revs, you'd see an increase in power, but at the price of high EGTs.



JK

 

[Reb.B]

the govenor set up is based on centrifical force. the more rpms the more force on the springs and that pulls the arm down. if u put stiffer springs, then it takes more force to open the weights. So, the arm will only go so high, and when the weights open it pulls the arm back down. u can shave the weight, add stiffer springs, put in a spacer, or pull the gov set up off for extreme racing. this was all explained to me by my bro (chrleb1) darn mechanical engineers, they know everything, lol.

 

[Jim Fulmer]

All the above is really good info, now if you get a chance to see it all work on a pump stand you will really start learning, this I got to see with a race pump, got to see fuel flow on a run but more importantly I got to see were the gov finally starts pulling back (fuel break away) looking at the dial guage on the rack..... cool stuff!





Jim





P. S. I never saw this post before..... bad name for it, pump operation, fuel plates and governors ect would have got more attention.

 

[DDunse]

Great post, very informitive for us less pump savy folks.

 

[Howard Durand]

JGK, Thank you for the time and effort it must have taken putting that post together.

It certainly improved my understanding of the process.