Dodge Cummins Diesel Forum banner

1 - 20 of 31 Posts

·
Registered
Joined
·
110 Posts
Discussion Starter #1
I installed a fuel plate cranked the star wheel and turned the anoroid in when i did i didnt get the jam nut tight and the screw backed out and then fell out. Is this a special screw or just a regular metric screw part number needed if special
 

·
Registered
Joined
·
293 Posts

·
Registered
Joined
·
555 Posts
sounds like a type of steroid to me man... hahah just messin. but really! same question here.
 

·
Registered
Joined
·
316 Posts
Try this,

Cumminsdatabase.com

It helped me out alot
 

·
Registered
Joined
·
3,578 Posts
What year truck is this?

Because you're post almost makes sense if it's talking about a VE pump; the aneroid being the AFC diaphragm assembly, and the screw being either the full power screw or one of the idle screws...

I don't know what fuel plate we're talking about here, unless you're talking about the fuel cone that is underneath the aneroid...
 

·
Tech Specialist
Joined
·
2,034 Posts
The AFC in an aneroid. Come on guys

The only screw with a jamb nut is the pre-boost, or smoke screw, and it is protected by a cover DSC00620.jpg - Image - Photobucket - Video and Image Hosting I hope you didn't drive with the cover off. If that screw is missing the truck will be a dog. The screw is special in that it has an allen head in it, but you should be able to replace it with a bolt from the hardware store. M6x1.5 seems to be a common size on the AFC so I would look around that size
 

·
Registered
Joined
·
3,578 Posts
The smoke screw on VE pumps fits on top of the AFC aneroid, above the fuel cone and starwheel, and also has a jam nut...

I never realized that vague language could make the two pumps so similar...
 

·
Registered
Joined
·
293 Posts

·
Tech Specialist
Joined
·
2,034 Posts
Someone correct me if I'm wrong here.

A person can turn EITHER that smoke screw OR the Star wheel correct to get the SAME adjustment. Correct ????
No, they affect two different things. The starwheel ajusts spring pressure on the diaphram, which effects how much boost it takes to get a certain amount of rack travel. You have to be in boost for the starwheel to come into play.

The pre-boost, or smoke screw as people like to call it, affects where the AFC arm will rest at in no-to-low boost situations. Max free-rev rack travel is limited by the setting of the pre-boost screw, while the starwheel has not effect in a free-rev situation.
 

·
Registered
Joined
·
293 Posts
The pre-boost, or smoke screw as people like to call it, affects where the AFC arm will rest at in no-to-low boost situations. Max free-rev rack travel is limited by the setting of the pre-boost screw, while the starwheel has not effect in a free-rev situation.
Ok.

I just recently turned the Star wheel a few revolutions towards the engine and it woke my truck up BIG TIME !! :beer

It does smoke a bit under initial WOT but then clears out.

How does one adjust that Smoke/Pre-Boost screw ????
 

·
Tech Specialist
Joined
·
2,034 Posts
Its easiest to remove the AFC and mess with it on the bench (good time to modify it for more travel :D), but it can be done on the truck. Remove the cover (one bolt is a break-off I think, and the other has a sfety/anti-tamper wire?) Then back the 10mm lock nut off, and your ready to adjust the screw with and allen wrench/bit. Just make sure to tighten the jamb nut when your done and put the cover back on. The screws are M6x1.0 and only a few mm long if you want to replace them with regular screws.


 

·
Registered
Joined
·
293 Posts
back the 10mm lock nut off, and your ready to adjust the screw with and allen wrench/bit.
Which way do you turn it and by how much ???
 

·
Registered
Joined
·
293 Posts
No, they affect two different things. The starwheel ajusts spring pressure on the diaphram, which effects how much boost it takes to get a certain amount of rack travel. You have to be in boost for the starwheel to come into play.

The pre-boost, or smoke screw as people like to call it, affects where the AFC arm will rest at in no-to-low boost situations. Max free-rev rack travel is limited by the setting of the pre-boost screw, while the starwheel has not effect in a free-rev situation.
I don't quite fully understand....

Can you give more details on these (2) adjustments ?
 

·
Tech Specialist
Joined
·
2,034 Posts

·
Tech Specialist
Joined
·
2,034 Posts
Which way do you turn it and by how much ???
Clockwise for more rack travel pre-boost, counter clock-wise for less. I have mine backed out all the way and still have to much fuel. Also depends on AFC position. A full forward AFC is like having the screw turned way in (if AFC were in stock position) and a full back AFC is like having the screw turned out (if AFC were in stock position)
 

·
Tech Specialist
Joined
·
2,034 Posts
Maybe a picture will help.
The preboost screw adjusts where the AFC foot rests in relation to the AFC housing at no boost situations.



The starwheel adjusts the amount of boost it takes for the AFC foot to start moving and when it will allow full rack travel.

Clear as mud?
 

·
Registered
Joined
·
215 Posts
Maybe a picture will help.
The preboost screw adjusts where the AFC foot rests in relation to the AFC housing at no boost situations.



The starwheel adjusts the amount of boost it takes for the AFC foot to start moving and when it will allow full rack travel.

Clear as mud?
Great post man ! :thumbsup thanks

.
 
1 - 20 of 31 Posts
Top