12 Valve 2nd Gen Dodge Cummins 94-98 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with P7100 Injection Pumps

just got a cummins, have some questions

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Old 10-03-2010, 08:39 PM
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Default just got a cummins, have some questions

well i just purchased my first diesel truck a few days ago, its a 94 single cab long bed with a 4.5" lift on 35s, 4x4, 5 speed. the truck has a boost and egt guage, but it doesnt smoke much so im not to sure on the state of tune the injectionpump is in, im sure somebody has turned it up in some way a little bit, the wastegate on the turbo is completely locked out and it makes about 32psi.

so i guess my main questions i want answered are these, first is my turbo at a safe level of boost or is the turbo going to fall apart? the compressor wheel has just about no play in it at all, its in very good shape but i dont know how long the wastegate has been maxed out for.

will turning the star wheel up make me loose my mpg? i know what it does, i know it adds more pre-boost fueling, but i cant help but think that when im cruising down the road at 45mph, im not making any boost, so am i just running the truck richer wasting fuel, or am i going to need less pedal to cruise making my mpg stay the same?

is there any way i can add more timing without having to buy any special tools?

and my last question is about the killer dowel pin, i know how to do the job, but i was just wanting your guys opinion on weather its easier to remove the radiator and everything to gain more room or just work around it? it seams like theres not much room between the timing cover and radiator.

a few of you guys have probably already seen it in my other thread but i added a few pics of the truck for those who havnt.

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  #2  
Old 10-04-2010, 12:31 PM
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32 psi on you stock hx35 is fine you may wanna read the afc tuning sticky at the top of the 12v bomb section... if i were you i would go through and re tune the afc the way you want it to be. the starwheel will give you a puff of black when you stomp it from a stop ( when turbo hasnt made boost) the best thing to do is to see what plate is in it now. and if the afc has been modded at all. then you can go through and tune it the way you want with the plate you want... i run no plate and i like it. hope this helps

---AutoMerged DoublePost---

KDP job is easy.. just take your time... and you need the tool to set the timing.. it is a must to b sure ur accurate.. and sweet truck by the way!!!!
 

Last edited by monster12valve; 10-04-2010 at 12:31 PM. Reason: Automerged Doublepost
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Old 10-04-2010, 09:12 PM
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i just did the kdp this weekend and it was very easy just took time and we didnt take the rad out and you dont need to unless you want more room
 
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Old 10-04-2010, 09:26 PM
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I also did my kdp with the radiator in.
 
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Old 10-04-2010, 09:30 PM
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Theres no need to remove the rad or anything else other than the fan and balancer
 
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Old 10-04-2010, 09:37 PM
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will turning the star wheel make you lose mpg at all?
 
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Old 10-04-2010, 10:07 PM
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Originally Posted by Dr. Evil
Theres no need to remove the rad or anything else other than the fan and balancer
You'll want to remove the shroud also wich will require removing the overflow bottle, and washer jug,
 
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Old 10-04-2010, 10:16 PM
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Originally Posted by cumminsp12v
will turning the star wheel make you lose mpg at all?
not if you dont have a heavy foot
 
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Old 10-05-2010, 12:01 AM
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Originally Posted by 12vcummins96
not if you dont have a heavy foot
but isnt pre-boost fueling pre boost fueling? when your crusing down the road you are not making boost, so are you wasting fuel?

the previous owner said it has no fuel plate, i didnt think that was possible, i just thought he didnt know what hes talking about. whats up with running no plate, is this just the absolute maximum?
 
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Old 10-05-2010, 01:54 AM
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removing the fuel plate makes the pedal control fueling to whatever the pump will allow without rpm input.
The AFC adjusts how much boost affects the amount of pedal input to fueling vs boost. It will hurt mileage if you push the pedal down to make smoke with no boost. Some people gut the AFC and make it just pedal input, some people fine tune it and make it work how its supposed to but with performance in mind.
That being said, no plate and star wheel cranked has made smoke hard to control when you have to roll off a red light with a cop watching you.

The star wheel adjusts preload on a spring that holds tension on a diaphram that has boost pushing on it. So the more you load the spring with the wheel, the less the fueling depends on boost.
 


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