InMotion CRD Tuning

geordi · **Posted:** Wed Mar 05, 2008 1:17 am

Assuming I find a Grand Cherokee with the same looking TCM as what I've got now... did any Grand Chrokees come with the 5 speed setup? Did all the engine options have the same transmission behind them?

And the big one: Can the TCM be recoded outside a vehicle? I do have a friend at a dealer, but he's in Indiana, and I'm not.

gmctd · **Posted:** Wed Mar 05, 2008 3:40 am

By '04 they were shipping the 5spd, and early year models that had gone out with the 4spd could be upgraded at the dealer - the xCM is stocked in unflashed generic and specific flashed versions - if dealer orders by your VIN, he'll get the module with your options, according to the build-sheet for that VIN - dealers can flash\reflash on-site, so you should be able to get one pre-reflashed - your friend would be the best source for more specific info and possibilities.

gmctd · **Posted:** Wed Mar 05, 2008 3:42 am

StarDreamer.us · **Joined:** Fri Oct 06, 2006 9:15 pm **Posts:** 63

After the changes what MPG are you getting? After the dealer reprogramed the unit my milage went to pot. Was getting between 25 -30 highway. Now I am lucky to get 21 MPG highway. I don't drive fast. Any ideas? 05 CRD sport.
Thanks!

Scott Langohr · **Posted:** Thu Apr 17, 2008 8:16 am

The single biggest thing that helped my mileage was keeping the MAP sensor clean. Did the EHM and SEGR and it stays in a lot better state but I still will clean it every 5,000 miles. It was pure crud when I bought it and wasn't a lot better after 5,000 miles but it cleaned up a lot easier. Did mods after that and it was way cleaner this last time. F37 was done to mine before I got it. Last tank was 28.2 MPG.

StarDreamer.us · **Joined:** Fri Oct 06, 2006 9:15 pm **Posts:** 63

What other mods did you do? I need to do something to improve the MPG. Thanks!

Scott Langohr · **Posted:** Thu Apr 17, 2008 10:26 am

Most of what I have done so far is listed in my signature. I had the fuel filter replaced with original mopar filter as soon as I got it home. I will make an upgrade there but have prioritized a list and that is down a ways. I am presently in the middle of the cummins in tank lift pump mod but it has not been finished yet. It is not particularly being done for fuel mileage but for an occational studdering problem at 55-60 mph and a hope to avoid any fuel heater puck problems. If it makes it run better though I may see an improvement but I am not unhappy with my mileage at present. I still have stock exhaust but that mod is tougher to hide until the 7-70 is past. I keep the tires aired up and found that 40 psi in front and 38 psi in back seams to be the sweet spot for the original goodyears. I drive my truck modestly and use the brakes as little as possible. Always in neutral when stoped waiting in lines. I used B2 and power service additive at the summer rate in that last tank. If you are going to change your driving style, disconnect your battery and let the ECM relearn your new style. Clean that MAP sensor!

chadhargis · **Posted:** Thu Apr 17, 2008 2:25 pm

I'm running the InMotion tune and it's SOOOO nice.

As for my mileage. Well, I do have more pep in the motor and I tend to use it. My mileage dropped 1-2mpg with the Stage II tune, but they also offer an "Eco Tune" that is supposed to increase your mileage.

chrispitude · **Posted:** Fri Apr 18, 2008 12:39 pm

Hi folks,

I emailed, then called Inmotion today to chat with them a bit to understand the difference between the ECO-tune and the stage 2 tune. Here is the email response:

Quote:

The Eco-tune provides the best fuel mileage gains in stop and go "in
town" driving only. On the freeway the Eco-tuning will provide no gains or
in some cases less fuel mileage then stock. For maximum freeway gains the
Stage-2 is the tuning you will want to use. To provide the maximum fuel
mileage with any tuning it is very important that you not only accelerate
very gently but you drive at or below the posted speed limits with the
cruise control on.

Per our phone conversation, here is what I understood. For city driving, leaning the fuel helps as not as much fuel is burned under load as you accelerate from a stop repeatedly. On the highway, the leaning means that a bit more right-foot is needed to maintain a speed against wind resistance, and therefore it burns a bit more fuel. I'm not quite sure I understand why leaning wouldn't still mean reduced fuel usage on the highway. My intuition feels that the right foot may go down more, but this is expected since the pedal puts less fuel in the engine, and it still ought to work out to an overall reduction (or perhaps no reduction depending on how the engine maintains a closed-loop feedback). However, my background is primarily with gas-burners (patooie!) and I suppose the dynamics of modern diesel engines may be different.

Anyway, just wanted to pass along the results of my questioning. For those of you looking to take some sting out of the pump prices, I hope this helps you make your decision.

- Chris

gmctd · **Posted:** Fri Apr 18, 2008 1:00 pm

"To provide the maximum fuel
mileage with any tuning it is very important that you not only accelerate
very gently but you drive at or below the posted speed limits with the
cruise control on."

The above ^ blurb tells the tale in it's entirety: lighten up or pay thru the nose - if the tune leans the fuel rate, yer foot is gonna go down more to compensate, plain and simple - even Cruise will call for more fuel to maintain set progress

The driver that buys a hot-tune while protesting 'it's for better economy' is the same guy that 'only reads the articles' in Playboy - gimme a break, here!!!

Anyway, the ORM or SEGR will increase fuel economy, as EGR wastes fuel by diluting the oxygen needed for complete combustion, so you mash down more to compensate - all ya gotta do, as recommended ^, is lighten up when you tune up (yeah....like that's gonna happen...not!!!!!).

Word up, dudes and dudettes...........

chrispitude · **Posted:** Fri Apr 18, 2008 1:19 pm

gmctd wrote:

The above ^ blurb tells the tale in it's entirety: lighten up or pay thru the nose - if the tune leans the fuel rate, yer foot is gonna go down more to compensate, plain and simple - even Cruise will call for more fuel to maintain set progress

Hi gmctd,

I confess I still don't understand this. The CRD's throttle is an e-throttle. If the tune leans the fuel, your foot needs to press down more and I understand that. However, wouldn't you simply end up putting your foot down to the point where the same amount of fuel is used such that combustion yields enough power to keep the vehicle in motion? To me, it seems that fuel economy depends on the efficiency of fuel combustion and not where your foot tends to take up residence.

Throttle aside, what about leaning out the mixture causes more fuel (not more throttle) to be needed to maintain highway speed against the same load?

- Chris

gmctd · **Posted:** Fri Apr 18, 2008 1:40 pm

You're on the right track, Chris, just maybe a little sidetracked - if the tune leans out the fuel rates for any throttle position, you will increase throttle angle to get the same power as B4: thus, fuel economy stays the same unless you lighten up, as blurbed^ - throttle is strictly fuel rate in a Diesel, where throttle angle also meters oxygen intake in those other engines, as required to maintain stoke - based on those concepts, your question is self-explanatory if you'll read thru it again:

"...you simply end up putting your foot down to the point where the same amount of fuel is used such that combustion yields enough power to keep the vehicle in motion? To me, it seems that fuel economy depends on the efficiency of fuel combustion...."

chrispitude · **Posted:** Fri Apr 18, 2008 1:58 pm

gmctd wrote:

You're on the right track, Chris, just maybe a little sidetracked - if the tune leans out the fuel rates for any throttle position, you will increase throttle angle to get the same power as B4: thus, fuel economy stays the same unless you lighten up, as blurbed

Okay, so this leads me back to my original thinking.

At cruise, the tune shouldn't use any more or any less fuel - assuming that you simply burn the fuel needed to keep you going. This is what I would expect. However, if there are other magic tricks being done in the ECO-tune (injector timing and such) such that you get a fuel economy improvement specifically when accelerating from a stop, shouldn't the overall net effect still be a fuel economy improvement, albeit one depending on the ratio of acceleration to cruise?

I am trying to reconcile all this information to understand how the ECO-tune could get worse fuel economy in mixed driving.

- Chris

gmctd · **Posted:** Fri Apr 18, 2008 2:50 pm

Prolly because there's a universal defect in the nut that holds the steering wheel, would be the pat answer - you control fuel economy in any vehicle you drive - better economy results in lightening up on throttle angle under all conditions - the vehicle\load will always take a given quantity of fuel to move the load - if ECM is programmed to reduce fuel rates for any given throttle position, it will take more throttle to give the same fuel rate to move the load - it's a catch-22 situation - now, by reducing EGR, engine can produce more power from the same rate of fuel, so if the driver lightens up, better overall fuel economy is resulted - however, if Cruise lightens up, but the driver doesn't, because of new-found power: Voila!! = the blurb is the all seeing, all knowing, oracle of truth and understanding - ommm....ommm....ommm......

chrispitude · **Posted:** Fri Apr 18, 2008 2:59 pm

Thanks gmctd. I agree that the nut behind the wheel is a significant variable. However, all other things being equal between the two (same nut, same highway speed, same in-town driving pattern), I'm still having a hard time understanding why Inmotion's ECO-tune is expected to deliver worse fuel economy in some cases than the Stage 2 power tune. If anything, I'd think the nut would be a bit more throttle-happy with the power tune than the eco-tune. I must have a mental block.

Don't feel obligated to spend any more time trying to get me to understand this.

- Chris

gmctd · **Posted:** Fri Apr 18, 2008 3:03 pm

That is the difference - engine under Cruise control will net improved fuel economy - engine under driver control is another story - that's what the blurb is telling you - gets worse with the hotter version, implied in the blurb - it's not mechanical, or eletronic: it's mental...............

CATCRD · **Posted:** Fri Apr 18, 2008 6:21 pm

Darn, I was hoping that the eco-tune would increase highway mileage by advancing injection timing. This is a known way to increase efficiency.

I'm scratching my head over how any tune could increase city mileage and not highway.

mark2m · **Posted:** Sat Apr 19, 2008 9:19 am

gmctd wrote:

That is the difference - engine under Cruise control will net improved fuel economy - engine under driver control is another story - that's what the blurb is telling you - gets worse with the hotter version, implied in the blurb - it's not mechanical, or eletronic: it's mental...............

Funny thing with what you say here. I seem to have an opposite effect. When I have the cruise set I get worse mileage. I'm not really sure why. I usually set the CC for just under 75mph and get 25-26mpg per the EVIC. Well when not using the CC I tend to drive faster about 80mph and get 27 sometimes touching 28 mpg. Only thing I can think of why this might happen is because the CC doesn't allow the Jeep to coast. I've noticed that is will hold you at that speed you set. Yes I know that is it's purpose but I tried a little test and found it odd. OK this is what I did.

I set the CC for 50mph and disconnected it. Accelerated down a hill to 60 mph and hit the CC. When it came on, the trans downshifted, TC lockup. I don't know but it slowed me down to 50. When I release it again. The RPM's dropped and I coasted freely. Got me. Just seems like there is no way for it to coast even when going downhill.

I also did notice that it feels like the CC gives it more punch when re engaging it or simply accelerating when commanding it. Just my observation.

gmctd · **Posted:** Sat Apr 19, 2008 10:32 am

Empirically, CRUISE is economical only on level flat terrain - hilly terrain, it will eat you out of house and home - ECM only understands maintaining SET speed, uses RESUME to attain that goal, no matter what the cost - try CRUISE'ing at 60mph, tap the brakes, slow down to 35mph, then hit RESUME - ECM assumes you just got the hi-sign from the rich teeny-bopper driving the street-racer in the next lane: full-W-O-T gonads-to-the-wall acceleration to previously-set speed - RESUME ain't good fer economy, so CRUISE is not always yer miracle economizer - for an even greater thrill, try that CRUISE-slowdown-RESUME thing towing a heavy trailer

geordi · **Posted:** Sat Apr 19, 2008 11:52 am

"For an even greater thrill..."

Like what? Watching the gas needle drop like a rock as you accelerate? Not a thrill, more like a horror!

InMotion CRD Tuning

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