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

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Old 03-17-2010, 08:59 AM
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Ok I am new to this I supose. I have a 97 3500 with a 12v and I am looking for the stock timing proceedure I searched yesterday and found the proceedure with a nice chart that contained pump cam lift and timing in degrees. Today I can't seem to find it.
I would like to start with the timing at the factory setting using the TDC lock on the cover. Does anyone have a link or some info on this? I am also wondering about this star wheel and fuel plate thing you are all talking about. What are they and where are they? Does anyone have pictures of them on here?
 
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Old 03-17-2010, 10:35 AM
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This is what a fuel plate looks like
http://www.mayerfarmequipment.com/ch...lates/6a_1.jpg
It controls how the motor fuels. A bigger plate equals much more fuel hence more power (around 140hp worth)

Which goes into your afc
http://dodgeram.org/tech/dsl/more_po...c_bottom18.jpg

And here is the starwheel
http://www.freewebs.com/nevrenufhp/MWpumpplugs.JPG
which controls pre boost fueling

But instead of setting it back to the boring factory timing, why not bump it to 15 or 16*? truck runs better and responds better to mods this way.
 

Last edited by 85_305; 03-17-2010 at 11:11 AM.
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Old 03-17-2010, 12:06 PM
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This is one of the better sets of instructions for timing the 12V out there:

TSB 18-10-94 Rev. A

Note that you can also time without measuring the lift at the pump, but it is somewhat iffy, as you don't really know exactly what you've set. Take what I'll write below as a secondary means, and at that, know that you should probably have some experience tuning and timing engines first.

You can time without measuring lift in the pump by:
  • turn engine to #1 TDC
  • Insert TDC pin into cam gear (also use an engine barring tool to turn) -- Once everything is aligned and you have measured (below) pull the TDC pin back out -- failing to do so will result in engine damage.
  • Measure the desired amount of timing increase into the harmonic balancer by dividing the diameter of the balance by 360 (degrees), then measure and mark the amounf of timing you want to increase.
  • Loosen the pump gear -- CLEAN the taper and make perfectly dry so the gear does not slip.
  • Reinstall the pump gear -- leave the nut just tight enough to hold the gear in place.
  • Spin the harmonic balancer backwards (counterclockwise) until the desired number of degrees for timing advance is met -- use a wire pointer to be sure of the distance. It will only take about 3/8" or so depending on the desired advance.
  • Tighten everything.
  • The reason you retard the crank position is that once it goes back to TDC, the pump will be advanced by that much.

Best time to do this sort of timing procedure is while you have the front cover off the engine to fix the Killer Dowel Pin -- you did do that, right? If not, do that before you do anything else!

I did mine last weekend like this -- was reasonably easy once I knew just what I was trying to do.
 
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Old 03-17-2010, 04:21 PM
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If all you want is stock timing this can be done much easier than measuring lift and checking charts. Roll the engine to TDC lock the cam to make sure it's there. On the side of the IP back by the gov spring plug is a large nut 7/8th I believe take that plug out. Inside there will be a pin with a plastic duckbill on it and a steel pin on the other side. Take that out. Look in the hole there should be a little arm that is in view that the duck bill will fit over it will be horizontal. If you can't see that arm romove the timing pin from the cam gear and roll he engine over untill you see thatarm in the center of the hole. Now pull off the filler tube tube from the gear case and take the nut loose and the IP gear. Now roll the engine to TDC again put the gear and nut back on and torque to spec. This will put you IP at factory injection timing. No special tools neede and quite accurate. Make sure when you put the duck bill pin back in you put it in with the steel pin towards the center of the pump and plastic piece facing you.
 
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Old 03-18-2010, 02:35 AM
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Thanks for the replies. I am going to attempt to set the timing to the factory spec in the morning. From there I will see how it runs. As it is it will hardly pull itself up a small grade. Though it wieghs over 10,000 lbs without a load I always thought it was sorta lacking in the power department. I wonder about the power upgrades, this truck is a wrecker and has 325000 miles on it. Im thinkin if I start playing around with more boost and timing it may finish her off.

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Oh The KDP is the reason I have found this site. I pulled the gear case cover off to install a new front seal and this dowel fell on the floor so I needed to find out what it was. Now I know. I got lucky it had wedged between the cover and the case and didn't hurt a thing just put a small dent in the cover and got stuck there.
 

Last edited by Overmodified; 03-18-2010 at 02:35 AM. Reason: Automerged Doublepost
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Old 03-18-2010, 05:35 AM
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I'd do several things in your predicament.

First, I'd make sure that the throttle linkage is adjusted correctly. This can be a problem.

Second, bumping the timing up a tad (15.5-16) is probably good -- Dodge retarded the timing on these engines for emissions reasons. Cummins typically runs more advanced when the engine is used in other applications.

Third, I'd want to make sure that the exhaust is not restrictive. Diesels need air in and air out -- the more the better -- and once you have some air flow, you can bump fuel to gain power. Some of these engines are spec'd by Cummins with as much as 370 hp and 700+ pounds of torque. Yours is probably set by Dodge at 180 hp and 450 torque (or so). Factor in miles and you are a dog, as you describe.

Fourth, I'd make sure that the fuel pre-strainer is clean. it can get filled with crud.

Fifth, it is possible that the timing has slipped and is not even stock, but you're working on that.

Sixth, if you are running an auto, it could be slipping. If a manual, the clutch could be slipping. Don't boost HP without making sure the transmission can handle it.
 
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Old 03-18-2010, 06:51 AM
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Fuel strainer? Where is that? You mean the fuel bowl?

To the original poster, 325k miles isn't terrible. In my opinion do a fuel plate and a fee other mods and bump the timing to 16* and you AND the truck will be happy
 
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Old 03-18-2010, 09:50 AM
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I have been an automotive teck for almost 20 years and looked after fleets of one tons mostly gas powered. The first thing I did was check the fuel flow and pressure. I originaly thought I would find a hole in a fuel line or a plugged fuel filter no such luck. The thing is just a dog. On the other hand it starts first piston up every time and runs perfect all day. Being a mecanic's truck you all know it is the last to get work done. I live in Ontario Canada. We have E-testing here and the testing becomes more difficult to pass as soon as your GVW is more than 10,000 lbs. I wonder if the truck would still pass the opasity test(smoke test) with the timing bumped to 16*. Although as it is I never see any black smoke and from what I understand they should give at least a puff under boost. I guess I could back it back to stock when it comes time for the next test.

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Oh ya it's a 5 speed manual trans and the clutch is new and upgraded!

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Linkage is working perfectly I have had the sending unit out and checked the sock in the tank I believe that is the strainer you are refering too. This truck runs the same with the exhost dis connected from the turbo. Those are basic tests that were checked before I even started asking questions and looking for info. I have even relaced the intercooler becouse it had a few pin holes in it.

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Ok I had to roll the engine back so the mark I painted on the harmonic is an inch away from the mark I painted on the crank sensor I'm thinking its sliped out of time????
 

Last edited by Overmodified; 03-18-2010 at 09:50 AM. Reason: Automerged Doublepost
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Old 03-18-2010, 10:43 AM
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Damn the fuel strainer is in the fuel tank?? How hard is that to check/clean?
 
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Old 03-18-2010, 10:43 AM
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Strainer is near the lift pump on the ****-poor fuel heater, not the sock in the tank.
 



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