hd99fxr3

I believe it was over on the CF forum, that I read that Rail pressure was used in the calculation. At the time my impression was that at any given time rail pressure, mph, etc, etc. would determine actual load on engine, where by high rail pressure for any given rpm would equate to light engine load, when the other measured parameters agreed. Again it was what I took any from the post over there. It made sense that if the injectors arn't bleeding pressure off the rail, and boost is low, throttle is not open more than other paramiters would indicate, the engine load is light. For my qualifier a simple example is needed. Because as I understand it, higher rpms=higher pressure produced by the CP3. For conversations sake let's say ( mostly because I don't know the exact PSIs ). At idle the CP3 produces 5k-9k depending on throttle position, warm or cold. At 1500 rpm empty on flat land 9k-15k At 2000 rpm same as above 15k-23k In each of these instances a specific RP would be needed to maintain the speed and rpm, if determined by the other perameters to be correct then logic would dictate a specific GPH consumtion (at that moment in time). So as long as the rail pressure stayed consistant for that perceived load, the ECM would give XX.X MPG on the readout. My understanding could be flawed, and I would be greatful if someone could point out my error.

As I understand it, the lie o meter uses rail pressure, mph and rpm to determine MPG. So if the mph and rpms are right, you would need high rail pressure for the perceived load to achieve high mpg readings on the lie o meter.What could be causing high enough rail pressure to cause the meter to be off so far?

Found this on the net, should help. Dodge_5.9L_03-07_injector_diagnostics.pdf

Since it starts just fine when cold, but is a hard starter when hot, it could be that the PO has the injector timing too far advanced. Hard starting when hot, could also mean that there is a heat / wear issue in the fuel pump, injector lines either not tight or damaged such that when cold they seal up fine, but expand and let air in when hot. Could also be in the wiring harness / connector, with a hot / cold issue. Somebody should be able to hook it to a dianostic tool, to see what is happening during a warm start. Low pressure to the rail when hot, could indicate CP3 issues, lift pump issues, filter issues. Just some things to ponder.

I had considered that, but then I thought that I was being paranoid, and decided to ask a few questions before I go to that trouble and expense.Anyone know what it costs to get that done?

What would be some tells that the previous owner changed the program in the ECM? I have black smoke come out the exhaust when I accelerate, it's enough that it leaves residue on the rear bumper. I've had the truck for about 6 weeks. Since I put a new thermostat in it seems as though the mpgs have been declining. Prior to the change of the thermostat, it would take forever to warm up, now it works like it should. Also I got consistant 18 MPG, hand calculated, now 16 seems to be the best. I would think that since the engine is warming up completely, the burn would be better therfor providing better mpgs.Thoughts?

No they are stock sizes, but you are right taller tires will skew mph slower and mpg higher.

OK so I understand that high rail pressure means the engine is not under load requiring huge amounts of fuel, add that to rpms, plus mph at any given time equates to xx.x mpg per the algorithem in the ECM.But high did it get 4mpg off? I've been zeroing it out at fill up and it seems to be doing better. I'll be checking it in the next day or so by hand calculation when I fill up. My hand calculations have shown so far that I'm getting just over 18mpg running 75-80mph and a bit over 14 when towing the goose neck 65-70mph, with some local running around thrown in to skew the numbers a bit. But still not bad IMO. But how can the lie-o-meter say I'm getting 18-22mpg when I'm getting 14-18? I've had the truck for 6 weeks and have not done any mods other than add a B&W GN hitch and get the Bed Liner sprayed in.Thoughts

Well in that case, it can only be something like, having a smaller rearend, frame flex causing problems, or something of that nature. It sure doesn't make since other wise. --- Update to the previous post... Went online this morning and found the 2012 load and towing specs. A 2012 Crew cab 3500 2wd short box has a 10,100 GVWR and a GCWR of 21K w/3:73 and 24K w/4:10 With the Mega Cab they are all over the place depending on St,SLT,Laramie,Longhorn. According to the PDF file the 3:73 has a higher GVWR (11,100) vs 4:10 (10,500) which makes no sense, as the GCWR is greater for the 4:10 by 2,700#. It is clear that the 3500 MC has both a higher GVWR and GCWR than a QC 3500 with the $wd versions going even higher. http://www.ramtrucks.com/en/towing_guide/pdf/RAM.2500.3500.Towing.Specs.pdf Perhaps the max tow pkg rating is getting confused with the normal spec. for towing without the Max tow pkg.?

Did some looking / asking around and the solution is simple. In the door you want to leave open, you will find the door latch mechanism on the side that mates with the pillar. Inside the latch is a black claw / u shape piece. Take a small screw driver and push down and back on the black piece. It will rotate down and in. Once this is all the way in the dinger will stop.

The difference between the Mega cab and Quad Cab capacities are due to the extra weight of the MC and the needed structural support. This extra weight must still be hauled around so the load amount has to be smaller by the extra weight of the cab. If you will look at the Dodge web site you will see that the capacity of the 3500 SRW is higher the the DRW for the same reason. It's the fenders and extra wheels and rims of the DRW that make the difference.For conversations sake let's say the GVWR of the three 3500 series trucks is 10K (easy math). And the curb weights plus allowable cargo, are as follows:3500 SRW curb weight is 8250 + 1750 cargo = 10K3500 DRW " " " 8500 + 1500 cargo = 10K3500 DRW MC " " 8750 + 1250 cargo = 10KThis is just a visual example and not the actual weights, but you get the idea. HTH

I'm in the South and will pull 14K about once a month 50 miles or less at 55-60mph or less on secondary roads.

Changed the fluid in my 11.5 rear end and used Mobil 1 Full syn. 75w-90. I have since read that the AAM rear end may call for something different. Manual calls for GL-5 syn. I believe. Mopar's fluid says for use in AAM axels. Is this marketing hype or legidement need?

Ok so it was just the way the light was reflecting. It looked like maybe some detonation going on because of the light. Piston is still awfully clean, doesn't have any carbon build up from the way it looks in the picture. You mention possibly loose head bolts, and a replaced head gasket. What happened?

What's going on with this piston? It's awful clean, and the areas I highlighted don't look right, could be just the light. Which hole is that?[ATTACH=CONFIG]3723[/ATTACH]

Those are awsome.

Mine were hard and brittle where they touched metal.

I would start thinking about the hoses. My '06 with 83k on the clock needed the hoses changed, where they contacted the engine, everywhere else they were nice and soft. Went with the Zerex G-05. Carquest was the only place I found that had it on hand.

I had the inner fender out, turbo air inlet tubing off and still couldn't get to it. :banghead:

You must have removed the alternator, to get the one on the hose going into the block?

I bought an extended warranty when I bought the truck. Knowing how they are about dening a claim, theres no way anything but Mopar is going to get added as an extra do dad. I was mostly just curious. Thanks

Well with as much spring tension that they have, theres no way you'll blow a clamp or hose off. But how in the world do you get them on and off? I even custom bent some tools to do the job and I still couldn't get the one on the block back on.

What a pain in the butt. Those hose clamps from H E double hockey sticks, wore me out. The top ones weren't so bad. The bottom ones especially the one on the block are shear madness. Finally took the one on the block and gave it a good fling, and replaced it with the screw type clamp.To add insult to injury after getting it back together, it took along time to get the check engine light to go off. Glad I did the work after the fact, as the PO had used green antifreeze in it at some point ( I just bought it a month ago). The temp gage works better now as well ( is warm faster).So far I've changed the oil and filter, fuel filter, tranmission fluid and filter and changed the fluid in the rearend. Now all that needs doing is the brake fluid and power steering flush and put a new serpintine belt on her. Sent the oil sample to Blackstone this morning.

Like I said not looking to make an enemy. Since you have ruled out all the reasons I can come up with for 6 cylinders being down on compression, and one with a likely hole in it. All thats left is bad luck?Sorry I couldn't help, and I'll still eat the crow if the cylinder walls aren't scored. Post some pics when you get it apart, if you have the time.

I really can't answer the rest of your questions, but I can point you in the right direction on the torque wrenchs. There are 12 in/lbs to 1 ft/lb. So your in/lb wrench starts at 10 ft/lbs and your ft/lb wrench starts at 120 in/lbs, so they both start at the same place. If the spec calls for something less than 10 ft/lbs / 120 in/lbs you need a 1/4 drive torque wrench. I would tighten the clamps for the injectors hand tight, after doing a few test runs with the 120 in/lb wrench setting. Since this is about proper bolt stretch and not about creating a bow in a selling surface you should be fine. If your not using new bolts the torque spec. is useless anyway for gaging bolt stretch, that will stay streched to that setting. That's why it is always recommended to use new fasteners for critical areas. i.e. head bolts.HTH