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  #11  
Old 07-16-2011, 10:03 PM
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Originally Posted by busymountain View Post
I just looked this over again - so I understand how this is working in the basic sense. The engine gets the turbo up to speed, it kicks in and then it uses the full capacity of the fuel plate. Is that right?
The turbo does not care what the engine itself is doing. All that makes the turbo 'light' is fuel. The fuel that burns and expands is what drives the turbo. The fuel plate is a "fuel limiter". It stops the rack travel to limit the amount of fuel injected.


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Originally Posted by busymountain View Post
I noticed that the truck will sometimes wrap up to 2200 rpm and max out with a temp of about 600F and stay there. Other times it will take right off with no limit on the tac seemingly and the temp skyrockets. Is this how the truck should be running? Or am I missing something?
Those are kind of strange symptoms. If it is only getting to an exhaust temp of 600* pre-turbo, you are not getting the fuel needed. It really sounds like the AFC is not functioning properly to me. What happens if you slide the AFC full forward?
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  #12  
Old 07-17-2011, 07:11 AM
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I had a guy's AFC not work at all, you might try taking the AFC arm completely out and just be easy on the throttle so you don't smoke everything out and see if it fixes the problem. The AFC should only control fueling under 5psi or so anyways so taking the arm out will just give you a lot of smoke before spoolup, but your foot can easily control this and will tell you if your AFC has an issue or not.
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  #13  
Old 07-17-2011, 08:48 AM
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Originally Posted by ISX View Post
I had a guy's AFC not work at all, you might try taking the AFC arm completely out and just be easy on the throttle so you don't smoke everything out and see if it fixes the problem. The AFC should only control fueling under 5psi or so anyways so taking the arm out will just give you a lot of smoke before spoolup, but your foot can easily control this and will tell you if your AFC has an issue or not.


I am going to slide the AFC housing forward toward the front of the truck first. If that does not work I may want to take this arm out at least temporarily. Do you have a pic or diagram showing the arm?:cool:
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Old 07-17-2011, 09:04 AM
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I personally would not recommend that you run it without the AFC much. As a daily driver you would be happier with the AFC in place with some tuning. Take a look at this article on tuning the AFC: http://www.dieseltrucksite.com/showt...=3178#post3178
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Old 07-17-2011, 09:53 AM
busymountain busymountain is offline
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Originally Posted by MnTom View Post
I personally would not recommend that you run it without the AFC much. As a daily driver you would be happier with the AFC in place with some tuning. Take a look at this article on tuning the AFC: http://www.dieseltrucksite.com/showt...=3178#post3178


I really appreciate your walk thru with pictures about this subject. It does not look like there are any breakable parts except maybe the diaphram. I will play with the AFC today and try to get it to work properly. I will also run on straight diesel just to confirm it is not a fueling issue but I am sure this is not the case.

These mods on the AFC appear as though it should only take an hour or so to complete. You do these mods for the power curve? in other words it is smoother power throughout the gears and excelleration?

I have a question about the diaphram and replacing it with a washer of the same diameter. This standard washer will not harm the diaphram even though the it is not cupped? I answered my own question, you would not be running still if it did not work right.:cool:

Thanks for the help everyone - I will keep you posted.

Last edited by stodg73; 09-15-2012 at 11:51 AM.
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  #16  
Old 07-17-2011, 09:56 AM
busymountain busymountain is offline
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Default Fuel plate adjust

I have got another question. When they installed the fuel plate they pushed it back reducing power because it seemed a little much. Is it better if I moved it back moving it forward a bit, do the mods on the AFC and then reduce power through the AFC?
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Old 07-17-2011, 10:46 AM
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You can put the fuel plate all the way forward if you want, but I would start with it in the middle. What kind of plate was installed?
The AFC is only for pre-boost fueling. Once you get some boost built (mine lights the turbo about 10 psi) the AFC foot moves out of the way and then the plate controls the fuel( along with your foot!). Ideally you want your truck to just haze a little when you first take off. Any more than that and you are wasting fuel and if you get too aggressive then it can start costing you fuel money in the form of lower mileage.
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  #18  
Old 07-17-2011, 01:16 PM
busymountain busymountain is offline
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Thumbs up

I believe the shop said it was a BD fuel plate capable of 350hp. I moved the AFC forward and retightened the hose clamp I added yesturday coming from the turbo to the AFC. Runs great now.

Sounds like I need to fine tune it for best mileage from what you are saying. I get a little black blow when in 3rd and I get on it a bit. I will strart looking for the haze in the mirror when taking off. I have to pull a trailer with it tommorrow about 150 miles so it should give me a good idea what its going to do.

If it does need adjusted a bit should I use the starwheel?:cool:
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  #19  
Old 07-17-2011, 02:33 PM
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Originally Posted by busymountain View Post
I believe the shop said it was a BD fuel plate capable of 350hp. I moved the AFC forward and retightened the hose clamp I added yesturday coming from the turbo to the AFC. Runs great now.

Sounds like I need to fine tune it for best mileage from what you are saying. I get a little black blow when in 3rd and I get on it a bit. I will strart looking for the haze in the mirror when taking off. I have to pull a trailer with it tommorrow about 150 miles so it should give me a good idea what its going to do.

If it does need adjusted a bit should I use the starwheel?:cool:
That would definitely make a difference! Glad you figured it out! a little black is not a bad thing, but if you can smoke out an intersection...... Anyhow, try adjusting the starwheel and set it to where YOU like it.
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1996 RAM "Custom Ground" 100 plate 3/4 forward, 300 injectors, 16.5 timing, Goerends Auto = 365HP, 833TQ Third Gen Rims, Aluminum Headache Rack
Duct Tape can't fix stupid, BUT it can muffle the sound
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  #20  
Old 07-18-2011, 10:49 PM
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Default still acting up

I took my road trip pulling trailer today. Started off great good accelleration and power. Around the 40-60 mile range it started to poop out again. No power, pedal to the floor to get 65 out of it barely up to any heat on the exhaust. Later after it cooled down and I began home still ran poorly. Then stopped for about 1/2 hour it took off like a truck. Ran great almost all the way home - on diesel only just to make sure. About 3 miles from home just after I got off the interstate it lost its power again. Cant really tell why.

I spoke with the shop who did the plate and he really likes the sticky plunger in the pump idea. Is there any merit to that one? Its pretty expensive. I asked him about possible problems with the AFC, he did not seem to think to likely. He suggested if we have problems after it heats up then starts to fail that may suggest a pump prob. (sticky plunger) Said he used to see alot of issues with that but that was years ago.

I have got an idea: The electric 3 way valves that control fuel type are set up for my truck - the "stock" version. Am I just demanding more fuel than those valves can produce. Sometimes maybe it just works because I have good pressure from the raptor we installed so it goes good for a while but then when it looses momentum it dies out? On the other hand it runs good up and down hills even when I let up on the excellerator to get off the temp for the exhaust.

Are those AFC units prone to problems? Intermitent?

Last edited by stodg73; 09-15-2012 at 11:53 AM.
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