Scottfunk

You might be right, I do remember hearing something about 315, maybe it was 315 =/- 5. I was so distracted by shiny new nozzles I was having a hard time concentrating.

Apparently they also have a one hour turnaround time when there's a shop hand available. Brand new genuine Bosch nozzles matched to 305 Bar =/- 5 Bar, "These are technically 50HP nozzles," he tells me. And I got a free T-shirt! Great experience all around.

Master Tech in Boise will pop them right in front of you for free. Mine were all sorts of bad...low pop pressure, bleed off, you name it. They are rebuilding them right now for $65 a piece, genuine Bosch parts and matched, not a bad price just bad timing. I will report back how it affects my situation.

@Mopar1973Man do you know of anywhere local that sells them? I'm going to have some extra time on my hands over the next few days and if I could use it to put this behind me that would be super.

Is this realistic? It's not that I can't afford to pay for pop testing but I can't afford to have my truck down and I can't afford to drop the injectors and have a guy tell me I can pick them up thursday and then listen to some excuse about how they won't be able to get to them until next month.

Is there any risk of harming engine components by performing a dead cylinder test mechanically; holding a rag against the back of the injector and cracking them open one at a time to observe changes in operation?

So the information the ecm is receiving from the sensor is correct and the value displayed is incorrect? Just making sure we're saying the same thing. Maybe I'll try a different MAP since they're relatively cheap and see if it helps.

My question then is, is this a mathematical issue within the Quadzilla programming or is it an issue with the sensor? In other words is the information skewed before the ecm uses it to process fueling values or is it skewed when the quadzilla is processing the information for display? If the information is skewed before the ecm processes it then the fuel tables are worthless because they're basically using an arbitrary value to compute fuel values.

@kzimmer @Mopar1973Man My boost with the engine off is 2 psi so I guess there's no telling how bad it's off at cruising speed. Is there any way to clean/calibrate it or do I just replace it?

So what if we take the trans out of the equation... What's a normal load/boost reading in park, idling? I read 6-7% load with 2 psi boost. Is that normal?

@Mopar1973Man I like the calculator at http://www.grimmjeeper.com/gears.html because it allows you to calculate your final drive ratio through your transmission, transfer case, axle, and tire size. With your 245/75/16's / NV4500 / 3.54 and my 285/70/17 / Allison / 4.10 my sixth gear is only twelve hundredths lower than your fifth gear in final drive. Rotational mass is definitely a consideration here but it sounds like I'm off to a tranny shop so see what they think could cause drag in the trans. @LorenS out of alignment is also a definitely possibility since I've never had it professionally aligned since I built the suspension in my driveway, but that being said other than being low on tread overall I took it to a tire shop to see what they would charge me for an alignment and they said "it didn't look that bad." Who knows what that means?

When I mentioned my EGT's in idle I was referencing in gear, in park they hover right around 300. I know this probably isn't the right forum for discussing the ins and outs of an Allison transmission but when I built it every clutch pack clearance was dead center of the service range. The trans appears to operate normally and at a constant throttle position maintains consistent RPM's throughout the gears. Hooked up to EFILive it shows all of the correct clutch packs engaging at the correct time and TC lockup pressure is 0 in free mode and 145 in lockup. Granted the Allison's internal parts take more effort to spin than your NV but I wouldn't think it would be that drastic. Also I'm running much higher than stock on the operating pressures, maybe 50% over. Perhaps generating that kind of pressure creates substantial parasitic losses? I am due for some tires and I will definitely be considering weight when I research, and possibly some aluminum rims could reduce rotating mass drastically? But still, stock trucks these days come with 31-32 inch tires so I don't feel like I'm way outside of normal operating range. @Mopar1973Man I used your recommendation for cruising RPM of around 2K when I regeared my truck with the 4.10's is there a chance that something about my setup would rather be a little lower? @NIsaacs the attached picture is my air filter and it is clamped directly on to the turbo. I'm sure it gets a little warmer than it would tucked in a fender well and that's something I have on my list to remedy, but watching my IAT's they never get way out of range...is there something about the length of my intake system that could adversely affect fuel consumption? And also, I haven't been across a scale yet but by my calculations the Chummy weighs much closer to 8K lbs with the added weight of the Cummins/Allison combo and 3/4 ton axles. If we consider that the Cummins calculates load pct based on boost psi at any give throttle request is there a chance that adding or removing fuel at any given point will change that relationship enough to move the load pct up or down? I'm just shooting in the dark here because I really am in the dark when it comes to tuning a diesel.

The turbo is the stock holset 35. The timing is in the 16's. Occasionally the load pct will drop below 30 and I'll see 20°. The truck has zero mods internally. At idle the egt's are over 400, 2 psi boost. I thought something was wrong so I checked valve lash following @Mopar1973Man 's procedure, they were out but not ridiculously. I put a dab of oil on the exhaust manifold at each cylinder when I left work and they were all burned off by the time I got home (not very scientific I know, but I believe it proves all cylinders are burning). @Me78569 I know your theory about it taking x amount of fuel to move a vehicle at any given speed so if that's the case what level I'm running on the quad at cruising speed shouldn't matter, it should just take less pressure on the pedal to maintain a given speed. What should I check next?

For those who aren't familiar my truck is a 96 GMC Yukon with an '02 24 Valve, it is backed by a 6 speed Allison transmission. The tires are 285/75/17 and I have regeared so that at cruising speed (70 MPH) I am right at 1960 RPM. I am currently getting about 10 MPG and I am trying to figure out why. I run a Quadzilla on standard tune, level 4 and I have a bit of a lead foot but most of my driving is freeway miles. I also run a FASS 150 and a 5" straight exhaust with 4" down pipe. Now then...at cruising speed I am approximately 20% throttle and my EGT's are in the low to mid 800's. My load ranges between 30 and 36% based on the slope of the road. The boost at cruise is 11psi and I never really paid attention to the IAT's until recently but they stick in the mid 130's; because of space constraints I use an air to water intercooler and I noticed a drip from the filler cap recently so there's a chance the fluid is low. I recently adjusted the valve lash and I have plans to clean the IAT sensor and MAP sensor in the next week but from what I understand about the sensors if they were dirty they would read low not high. I am admittedly not an expert in the field, in fact this is the first diesel truck I've ever owned or even driven. So the question is: Where can I start looking for inefficiencies or out of service conditions that are burning extra fuel? I would really like to take the old girl to the coast in the spring but at 10mpg I'd need a second on the house. Any help is appreciated.

@mossyoak71 I'm ecstatic to report my transmission finally performs as it should. No more taking her out of gear to stop, seamless power from 0-70 acceleration, turbo spools right up. It feels amazing. As an added bonus I found one of the motor mounts I had originally built (very cheaply) was broken causing a horrible vibration. So i took the time to properly square up the engine and built some new, much improved motor mounts. No more vibrations and as an added bonus I was able to install the belt fan for the first time ever and ditch the stupid electric fan. And then...yes there's more! When I was dropping the transmission I literally DROPPED it! I broke the external transmission cooler I had mounted underneath, also with an electric fan. So I was forced to explore the options to cool the trans. Turns out the trans cooler in a Duramax truck radiator is exactly the same dimensions as the original trans cooler in my 96 radiator, except the ports were different. So I pulled the tank off, swapped out the coolers, and put it back together. Factory trans cooler. In the spring I'll fix the auxiliary trans cooler and mount it in front of the radiator and have a bulletproof setup. It took an entire week, 8 hours a day to get everything back together because of the challenges (thank god for PTO) but it's back together now and better than ever!

@mossyoak71 Even after I got the ECM reprogrammed it still didn't want to stop. It would, just took some effort. I'm pretty sure I have also been battling a defective sprag clutch in the torque converter. I had the supplier send a warranty replacement, just waiting for time to swap it out...and rebuild the trans because the sprag being locked up scorched the trans fluid. Sucks but I'm becoming something of an expert on Allisons.

It really doesn't matter which trans you have. I originally had a manual ECM with my Ally. I got a real low stall TC and when I would come to a stop, as soon as the RPM's dip below 800 the manual ECM thinks it's stalling and adds fuel. If your tc is stock you'll probably be OK but if it's anything lower than that you'll probably notice the effort getting it to stop. The auto ECM is OK with about 765 RPM's in gear and stopped.

Yeah I know. But a lot of folks also don't know it can be done that way. From what I've seen unless an axle has been completely neglected there's no reason the r&p can't be reused. I found separating the bearings from the pinion and the carrier to be the most frustrating part of the job. This weekend I made a homemade separator otherwise I would've been unable to complete the job. I guess what I'm saying is some research and a little outside the box thinking can save a big pile of cash.

I dunno about that. I regeared my whole truck for under$200. I haven't gone for new bearings yet but when I junk yarded the rear gear I took all the bearings too, and the front gears I bought off eBay came with bearings. I picked forthe best ones, greased em up and let her rip. Now for a front driveshaft and I have to learn how to operate this cad thingy and I'll be ready for winter. Me thinks winter will be a rough one this year.

Same size tires, 4.10 axle, but apparently Allison transmission is quite the different beast than the 48. I love the combination myself. My wife runs a thrift business on the side and she's always buying stuff from auctions. There's an auction house here that has tires often. I literally paid $13 for the set and mounted them at home by hand. If I knew what size I could ask her to keep an eye out.

Guess I'll run the Chummy across the nearest cat scales this weekend. Frankly I have no idea whatsoever what she weighs. Front, back, or total. Thanks for that info. When my wife bought these tires for me they were used, and had a wear ring right down the center from being overinflated so I erred on the side of underinflation to avoid making it worse.

Since were talking tires...I'm trying to figure out what the ideal pressure is but everything I read says check the door jamb. Problem with that is my Chummy is much more like your guys' trucks than what it was originally designed as. The tires themselves say 80psi max and right now I'm running 38. My contact patch is almost a whole square foot. I feel like a few more pounds would be easier on the fuel but if the trade off is premature wear then it's probably not worth it. What psi are you guys running?

What I'm looking for is the rest of the settings so I can start with a tune that works well and see if I can squeeze a little more economy out of it. All of this stuff: Power Levels: Timing Fuel Load Timing: Low PSI Timing Reduct: Timing Reduct Scaling: Light Throttle Timing Adv: Light Throttle Timing Load Limit: Timing vs rpm 1500: 2000: 2500: 3000: Timing Max: Wiretap Pump Stretch: TPS Pump max: TPS Pump Min Minimum Pump Tap Fueling Percentage: Pump Low Boost Scale PSI: Boost Scaling: RPM Limit: Power Reduction: 0 PSI %: 1 PSI %: 2 PSI %: 3 PSI %: 4 PSI %: 5 PSI %: 6 PSI %: 7 PSI %: 8 PSI %: 9 PSI %: 10 PSI %: 11 PSI %: 12 PSI %: 13 PSI %: 14 PSI %: 15 PSI %: 16 PSI %: 18 PSI %: 20 PSI %: 22 PSI %: 24 PSI %: 26 PSI %: 28 PSI %: 30 PSI %: But for the default tune. Like if you click on custom tuning and you have your own tube loaded you can see all the settings, but if you look at default it doesn't have an edit button. Perfect. I missed that somehow. Thanks

Does anyone know the settings for the default tune in v2 tuning? My truck runs amazing on level 5 with default tune and I'd like to use it as a baseline and monkey around with things from there but it doesn't give you that option.

I did some digging and according to nada your dodge ram trucks are around 6000lbs. By my calculations my Chummy is close to 8000lbs. Is that enough to make a significant difference?