Sorry, this is not trans tuning related, but I am hoping Superchips can tweak the our truck's code to make the decel fuel cutoff engage quicker. My wife and I just drove out from SLC Utah to OKC Oklahoma over the weekend, towing her car. I had the truck loaded to 6500 pounds, just a little under max. I happened to see my truck activate a decel fuel cut-off when we were going downhill several times. I ran the SC 91 tune, had the tranny in tow/haul mode, typically with cruise on (but not always), and was going around 65 mph. I noticed the truck would downshift, fuel flow would drop to 1.15 to 1.35 gal/hr, and then if the hill or decel condition continued for a few more seconds, fuel flow would drop to 0.0. However, as the hill leveled off the cruise would pull the throttle cable and fuel flow immediately resumed...or if cruise was off, I'd press the gas and the truck responded in the same manner. This happened far more frequently in the Utah/Wyoming mountains than after we got into Colorado and Kansas...although I did get it to engage while coasting to a Tollroad booth yesterday in southern KS. It would even continue below 2000 rpm, but would resume fuel flow before 1500 rpm if I remember correctly.
I found it peculiar that the truck downshifted each time before it engaged the fuel cutoff. I posted a picture in my gallery as I have maxed my pic attach limit here...https://dodgeforum.com/forum/members...car-in-tow.jpg I am using an MPGuino with a wire tapping #1 injector. My light failed on my driveshaft speed sensor so I could not get any speed/mpg info this trip.:banghead:
Scott, I hope this helps you find what I am talking about. Until this weekend, I had not seen this activate. I'd like to see it pull fuel flow first, then downshift to aid decel, but I do not know if it would work as well this way.

 

Yes, it does, thanks!

Roger that, thanks again Papa.

-Chris

 

Davb673, I have to admit most of your post is over my head but, SC does NOT recommend using 91 Perf if you have over 1500lbs. Given this, if you were to test again and tune to Tow, do you think you'd see the same results?

 

MDSBigPapa, I must have missed that on SC's note. I use an MPGuino (effectively an opensource Scangauge) to monitor my fuelflow, as I have been working on ways to increase the truck's fuel economy for the past year. No dramatic success yet, but perhaps in time. However, I did not expect much on this trip (I did get 12-14 mpg). The fuel cutoff, if the programming is modified, could benefit all of us with a Superchips tune. My 91 VW Jetta had a similar thing programmed into the engine computer. When coasting, fuel flow would be cutoff until the accelerator was pressed again. That car was a 1.8L w/5sp, and I could get 31-33mpg without any hypermiling tricks. Our trucks seem to have the fuel cutoff, but it is designed in more for deceleration, not for improving fuel economy. I was pleasantly surprised to see it (the DCFO), but disappointed that it took so much hill and/or weight to make it finally surface. It seemed to only activate w/closed throttle, engine above 2k rpm, after the tranny upshifted a gear to aid deceleration and it still took several seconds coasting in this condition before it would finally activate. It would hold down to about 1500 rpm, and I'd see fuel flow resume about that point. I am hoping my writeup above can aid the Superchips' engineers in cracking the code. I figure if Superchips can get it tweaked to activate w/closed throttle, engine above 1700 rpm, and the tranny be in D, 4 or 5, and after coasting for maybe a second or maybe even upon throttle valve closure, that should allow the DCFO to engage. We'd all enjoy the benefits of wasting less fuel without noticing a thing.
Actually, I do not think the tune would make a difference but I could be wrong. I suspect the tow tune probably doesn't have as much ignition advance, but I do not recall hearing any ping. I think my overheat is due to my Efan not quite pulling enough air (2700 cfm), so I am going to stick the clutch fan back on tomorrow and check my cooling temps. Or maybe I'll switch tunes? I had not driven that mountain with that big a load before, so it was a bit of a surprise. True, there are no hills nearly that tall here in OK/TX, but I expect I can see if the fan/tune makes a difference.

 

I received word back from the engineer on your request and he basically said that the way we perform our tuning currently is by controlling the "when" and "how much" in your vehicle but what you are asking for would require rewriting the OS itself.

That is not an easy task since there are limitless calibrations out there not to mention PCM architecture differences throughout the years of production.

That option in their minds carries too much risk to consider.

Scott

 

Understood Scott. I appreciate you looking into it. I agree, with the changes in Dodge's PCM software over the years, rewriting the OS would be a nightmare.

 

Sil,

I downloaded all 3 of your excel sheets for my new 3865 tuner. I am trying your newest trans settings. Installed them tonight. For some reason i didn't have the mph option you set it for so i choose the closest speed. Plan to play with it over the next few days. Is there a difference in application/style of your 3 shift schedules for the 08? or are they just improvements over time for the same application?

I am currently running 87 tune TP set to superchips right now. I definitely plan on playing with TP as well since i tend to think it shifts slow. From what i have read thus far (pages 1-130 and then 214-todays posts) sounds like maybe 10% is a good starting point?

Once you have a shift schedule set, will switching my power setting reset or maintain my custom shift schedule?

My goal is to get a tune that helps or maintains my milage but has a much better then stock trans tune. Once i get this figured out I figure i can play with a more aggressive tune for fun around town.

 

Alright im sure this has been answered but i have looked through so many pages and can't find anything. Has the Trans tune came update came out for the 2006's i just ordered a cortex and was hoping that it was out already.

 

Yep, 2006 is applicable with the advanced trans tuning feature.

Scott

 

what tuner do you recommend from superchips is it the flaspaq or the cortex? with these tuners do you get software for your laptop for data logging? and if so does it support mac os systems??? im new to owning a hemi i had an 01 with a 5.9 and i bought a hypertech programmer and had issues with it so i wanna make sure i make the right choice. so since everyone on here seems to have one of the best knowledge bases ive seen about dodge rams please help me decide. thanks guys