DrJekyll86

I’m running stock gears, auto trans with 265/75/16 What’s the upper safe limit for sustained egt on these 5.9s? I’m only on my second towing trip and getting used to when to shift in/out of overdrive. Im towing a 9500. Lb rv. With O/D off the rpm run 2300 ish at 58- 6ph. I have a 5 in exhaust and noise is fine except at 2300-2500 rpm where cab drone gets out of hand. Unfortunately, that’s my towing cruise speed/rpm. Im usually under 1100 egt in overdrive but not sure really where the safe limit is. There’s plenty of power in OD, just want to watch egts.

Thanks for the info on the crank sensor. It's been a few days since the it was changed and I haven't noticed a delayed start since. When I experienced the cel last week, there was a momentary engine hesitation while driving and ran fine afterwards, which was a 10 min drive home. On the surface it seems the crank sensor could be the culprit of intermittent delayed starts if the sensor can take sometime to fully degrade rather than go out all at once. I haven't noticed a delayed wait to start light. I just walked out to check and it lights up immediately. I cycled the key several times with the same result. It was the first light to illuminate every time. I will keep an eye out for it, though. I was wondering the same regarding air in the system. It didn't quite seem to make sense, however, since the AirDog is supposed to significantly decrease the amount of air that reaches the VP44 and the entire system should be positively pressurized, resulting in fuel exiting the system rather than air entering the system. I imagine a damaged o-ring would show a pretty significant leak at these pressures if it were to allow air to enter the system when the engine is off. I could certainly be wrong though. I'm no expert in fluid dynamics.

I did find that but I don’t have an active excel sub and Google sheets didn’t like the file. Are the key values excel file row numbers? I originally wanted to know because I purchased a tune and couldn’t get it imported, so decoding the json and manually creating a tune was the next step. Fixed the import issue but still curious about the software.

If you are on an Apple device and downloaded tunes are not showing up in IQuad, you can send the file to IQuad from the file itself. 1) download the file onto your device 2) go to the file in “Files”. If the file icon is not visible on your screen, swipe all the way left and search for “Files”. Will be an icon of a blue folder. 3) find the file and press and hold on the file, should be a .json file. 4) click “share” 5) choose the IQuad app to open the file in the app. This should open the tune in the IQuad app under custom tuning. After naming the tune, it moves you to the custom settings screen where the imported tune is loaded. Save the tune and you are good to go. I could’t find this thread so made this post that includes a few screenshots.

I’ve spent some time on the truck this week. I meticulously looked over the fuel system and see no indication of a leak. However, my crank position sensor took a dump on me this week. Luckily I was in the garage when it happened so I wasn’t stuck in a parking lot or on the street somewhere. Is it possible for a failing crank sensor to cause inconsistent crank times? It threw cel twice this week with no noticeable impact to the engine before failing completely today. Engine would crank but not start. I would think if it was impacting crank times it would have thrown a cel the past few weeks as well but not sure? Curious what the experts say on this. Seems to be fine since replacing the crank sensor.

I noticed downloaded Quadzilla tunes are in json format. Is there a schema for key value pairs available to decipher the tunes? I’m new to tuning and Just trying to learn a bit more about how this all works. The data doesn’t read intuitively, like {“max valet power mode”:”30”}. Instead all values are coded, like {“135”:”144”, “15”:”6”}

I’ve noticed a lot of people have issues with getting IQuad to recognize an imported tune on Apple devices. I had the same issue and never found the pinned topic in the tunes section that discussed importing tunes. I was able to figure it out this evening and here’s how I did it. After purchasing a tune, click download in the browser on the Mopar1973Man order confirmation page. The file should now show up in your files folder. (Images are blurred because I held down on the iCloud to highlight them). If you can’t find your files icon, sipe all the way left and search for files. The icon looks like this. From there, the downloaded file is probably in your downloads folder or your ICloud Drive folder, depending on how you have your device set up for downloads and file sharing. find the tune you downloaded, usually named “<tune name>.json”. I recently downloaded a tow tune so it was named “Tow.json” Touch and hold the icon and click share. The IQuad app should be available in the list. Click to send to the app. Boom! The IQuad app should open to the new tune, allowing you to rename it and takes you to the tune itself in the customize tune section to verify and save the settings. Hope this helps!

@Tractorman I’ve been out of town for work this week and haven’t had a chance to really dig in or check back here too much. I did another scan for leaks before I left and nothing stood out. The quad arrived this week so I’ll be diving into that when I get home and will be able to take a closer look at possible fuel issues/grounds. I cleaned up the battery terminals when I did the WT mod and give them a wiggle test regularly just to be sure they are tight. Around the same time I cleaned up all the grounds while investigating the abs/emergency break light combo. I need to investigate that further but I believe it’s the harness connection near the back of the cab on the drivers side or farther back. There’s no indication of a bad battery and when starting the motor turns over at what seems to be an appropriate rate. And there’s no discernible change in starting rpm between starts, regardless of whether ignition is delayed. So all that to say, no real updates. Hoping I’ll be back home this weekend and able to do a more thorough look.

Royal, that’s something I haven’t considered. However, it’s intermittently occurred in our flat driveway so seems to be no correlation there. IronForger, I’ll give that a shot. I’ve checked multiple times for what i’d typically consider a fuel leak - an obvious drip or wet spots at the connections.

I had to check to be sure - the Airdog harness has a direct connection to the battery with a switched relay controlled by the original pumps harness.

That’s good to know regarding high pressure. The new LP harness plugged directly into the original fuel pump circuit so I imagine the switch to power is controlled by a relay. I would have to look up a diagram or trace the wires back to know for sure though.

Thanks, John. There’s no discernible change in cranking rpm. My batteries are good and recently did the WT mod. Terminals might get changed in the next year or two, not because they seem loose or too terribly corroded but because it was previously a light duty farm truck and appear chewed up a bit from jumper cables. I’m a fan of clean hardware. The variation in cranking doesn’t seem to follow a pattern: cold vs warm, sat for days vs a few hours, etc. It can crank right up in the morning but take a couple seconds to start back up at the gas station. Next time out might be the opposite. I’ve double checked my grounds and might go over them again. I know for sure the pump consistently cycles when the key turns to on. The new ones are quiet enough you actually have to reach down and put a hand on it to be sure. It does eventually start every time. It never attempts to fire up and then not. The moment one piston fires it lights right up. Just seems odd. I’d rather know if this is an indication of future problems I can head off early or if it’s a non-issue. I k so there’s a big asterisk here with not having a fuel pressure gauge… the quad might have to come sooner rather than later.

I recently installed an Airdog lift pump (Airdog II 4G DF-100) and since then I’ve experienced varying crank times. Prior to the install, the truck would turn over for maybe 0.5 second before firing right up, every time, without fail. And it feels like half a second is generous on the long side. Since the install, crank times vary between the 0.5sec up to 2 seconds. The engine seems to run a bit smoother since the install and no indication of a misfire. The most noticeable impact of the install is varying cranking times. From what I’ve read the symptoms could be due to worn injectors or poor fuel pressure but would love to hear the collective thoughts of the crew here. I’m thinking maybe 1 or 2 injectors may be going bad. Could crank duration be affected by which piston is up next in the firing order when an injector is failing? I’m sitting at just over 140k miles and I believe I’m on stock injectors and believe in at the end of their life. Injectors are planed for when I do the quad soon. We did test the pump, which the newer air dog lift pumps are designed to build pressure and shut off until the engine is cranked. I know and have observed the pump cycling when the key is turned to on, just before cranking. We tested flow when we installed it by observing the return flow line draining into a bucket while the engine is running, which I admit was weak but the documentation also states the original return line will continue to function as before so volume will be split between the two. The install has been in for some time now and no detectable leaks have been observed. I don’t have a set of gauges yet. My next upgrade is a quad with fuel pressure, trans temp and egt gauges but life keeps getting in the way of the truck budget.

I’ll look at the quad + injectors first. I read the quad setup articles and see you can essentially detune the truck with larger injectors but can’t over-tune an injectors max output. Makes sense. I’m looking to make a fun daily/tow vehicle that can get great mpg if I show some restraint. I’d prefer fun/dependable/bulletproof truck over a hour/torque monster but like to have power in tap when needed. I’m sitting on 265/75/16 and not really looking to go bigger. Has the auto trans and I’m pretty sure it’s stock gearing. Thanks! Just curious, what’s the risk of running larger injectors and the need to watch gauges? Potential EGT issues? I’m familiar with lean/rich fuel dynamics on gas engines and the impact on heat but I’m sure it’s different for diesels.

Just wanted to express appreciation for communities like this. I haven’t posted/interacted much but I’ve been reading and applying what I’ve read. I’m too green to really chime in other than questions, anyway. I picked up a truck a couple months ago with the intention of building it into a tow rig. It’s not a full time commercial rig but I work remote and the wife and I want to be on the road a lot, so getting the truck ready was a priority. Doing WT’s ground wire mod fixed the annoying TC cycling issue and the vp44/injectors sound happier with a lift pump. Reading here has me settled on a Quadzilla and likely 100hp injectors (rather than 50’s and wanting to upgrade soon anyway). Trying to decide if I should wait to do injectors until I do a turbo (for towing) or if it’s worth doing now and adding turbo later. I’m learning a lot by going through the articles on here. Anyway, it’s a slow n’ rainy Sunday here and just wanted to say thanks.