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Messages posted by: GreenDieselEngineering
Forum Index » Profile for GreenDieselEngineering » Messages posted by GreenDieselEngineering
Good question. It appears to be more pronounced with the hot tune. The rate of decreasing the fuel when releasing the pedal is the same for both tunes, but the hot tune allows 15-20 % more fuel in high load driving. So with the hot tune the decrease to zero fueling takes slightly longer and there is a noticeable difference.

We have spent the last few days working on optimizing the fueling ramping rates based on throttle input. The results are very promising as we have still been able to keep the "clunk" down to a minimum and the vehicle does not feel like there is any surging or positive torque when tipping out of the pedal. This part of the tune is very subjective to feel and 10 differenct customers may have 10 different preferences. The goal is to find the proper balance where no one even notices it...if it is transparent then we did a good job.
The tunes have changed the pedal response significantly. One of the areas we focused on was to minimize the "clunk" in the driveline due to torsional lash wind-up. In order to do this we added filtering to the pedal, which tends to make the response more smooth, but slightly slower.

We would like to get a better understanding of your driving preferences for pedal response (snappy vs. smooth) and the relative importance of driveline clunk...does it matter? Several customers have noted the increased "coasting" with the tune, however, this may be a hinderence for some drivers. This part of the tune can be revisited and it should not effect fuel economy.

This is a democracy so vote early and often! We look forward to hearing your suggestions.

This is true, regardless of the firmware in the ECU. Both our tunes will have the latest glow plug calibration installed. This at least makes sure your vehicle is up to date in terms of glow plug service releases. We updated all our cals on 20 October.
There are no issues if one unplugs the glow plugs, other than the constant CEL. We could turn off the glow plug CEL if customers really wanted it. Down in Texas where you are at, the glow plugs are not used that often and most likely they will not be fully powered in order to acheive the regulating temperature. The northern portion of the US and Canada tend to put the glow plugs through more exercise and would have a higher percentage of failures. Having the latest calibration of the glow plugs is the most important factor as it works to reduce the maximum plug temperature and increase life.

If you had a cold snap in Texas and the ambient dropped down to 15-25 F overnight, the CRD would be very hard pressed to start without the glow plugs operational, unless the block heater was plugged in all night. After starting, the engine may have some misfire for the first 2-3 minutes without glow plugs working. You may want to test this on your vehicle a few cold mornings to see the effects in your region.

It would be interesting to know how many owners have actually had a glow plug issue and what region of the US they are located.
We tried to adjust the curve that controls the instantaneous fuel economy, but there are several inaccuracies in the lower end of the fueling curve. With the GDE tune less fuel is used and it operates more at the lower end of the inaccurate fueling curve, thus making the EVIC read slightly higher fuel economy. The software is very limited here.
The Body Controller is a separate computer from the engine contoller and that TSB will have no effect to the tune. We are going to take more measurements in the coming days and then look into the TSB stutus on our 06 vehicle. Minimizing the leakage rate will only extend battery life.
The TCU uses several different signals together to determine the shift points.

Vehicle speed does not seem to be a critical factor, at least changing the revs/mi in the cluster did not have any effects. There are other internal checks in the TCM that are limiting the shift points.
Yesterday after driving our 06 with new red top, the voltage after shutdown was 12.8 V (warm battery). This morning the voltage (with key off) read 12.3 V. The readings vary wildly depending on the conditions.

We also measured the current draw inherent with the vehicles after sitting overnight. Both the 05 and 06 measured almost 1.7 amps of current across the terminals, not sure how this compares with other vehicles yet. Most vehicles have some sort of leak rate for current, usually low enough to be able to start the vehicle after a few weeks of sitting (in a perfect world).
It is a 150k factor converter based on our information. Not sure what that equates for the stall speed, but it is the same as production.
We have successfully translated the glow calibration from the latest release and installed it on all the tunes we offer. With this, no matter what ECU part number one has, with the tune the glow plugs will be operating at the safest temperature (as best as it can be). This will help to ease worrys about glow plugs for customers with older vehicles looking for an update.

We did our best to prevent shudder initiation with the ECO tune by limiting the amount of torque available between 1650-2100 rpm. We were not able to get shudder even when pulling a trailer, the transmission would hit the 'unlock' region before the shudder started. This was accomplished with the F37 traditional damper converter. The ECO tune has not eliminated all shudder in every customers vehicle. There is just too much variability in the amount of torque the stock converter can safely handle and if you already have shudder the ECO tune will most likely still produce enough torque to cause shudder, there is no fix for a weak TC. The HOT tune and turbo kit both cause massive amounts of shudder with stock converters...this is the main reason we opted to update both our vehicles with the new Mopar unit.

It might be nice to experiment with different k-factors, but the Mopar unit is not very far off base, as the stall speed changes so does the multiplication factor. The k-factor is a trade off for fuel economy (less slip) in light load driving and having the rpm in the best band during heavy load driving. Keep in mind, the new Mopar unit is used on all the new Jeep diesel products sold overseas and these engines have more power. The best part of the new converter is the higher spring capacity in the lock-up clutch as this is the problem source with the current TC in the KJ. We understand your concern and it is rightly based, but the new TC is a big step in the right direction.

Best of luck!

We measured the voltage during the first second of "key-on" before starting a cold engine. There is some draw from the glow plugs during this period. Today with the new optima red top we measured 11.2 V and the engine started in 1.35 seconds. The battery voltage seemed to have a strong positive effect.

12.1 V is not a bad number with no loads, try measuring it with a load from the glow plugs in the morning. A failing battery will have a larger voltage drop, ours was down in the 10s V.

We trickle charged it for 10 hours and measured voltages around 11.7 V, then after three days of sitting the voltage would drop to about 10.7 V.

Here is a rundown on the 06 with new battery voltage measured at the terminals from this evening after sitting all day at 55 F.

key off 12.17 V
key on 11.75 V during glow phase, steadies out after several seconds at 12.05 V
cranking 9.70 V lowest visibly seen on hand held meter
running 14.30 V
shutdown 12.50 V trickled down to 12.2 V after 30 seconds

Colder temps will drop all these numbers. We have seen cranking voltages drop down in the 7s at -15 F.

The optima has very high power density. A good battery for this application. It would be interesting to know how many people with failed batteries ever charged their battery for any reason? The gel batteries require a specific charger designed to charge in a specific manner to promote battery life. We only have a regular/deep cell charger and have a feeling this contributed to the demise of the battery. Time to go shopping for a new charger...
We have not tested other starters, but there are several on the market that would provide faster cranking speeds. It would be important to make sure the pinion is matched for the flywheel and the alignment is correct. We are not aware of any off-the-shelf starters for the KJ and some manufacturer design work might be necessary.

During our cold start tests the last few days, we have noticed significant variance in start times based on battery voltage. The red top in our 06 is starting to go...fast. With the coolant temps around 5 C the 2006 KJ started in 2.35 seconds and the battery voltage was at 10.7V. In the 2005 KJ the start only took 1.0 seconds and the battery voltage was at 11.2V. The lower system voltage affects the glow plug temperatures and the voltage supplied to the injectors. This reduces the engine's ability to have optimized combustion. Once the engines started and the alternators kicked in, the voltage on both vehicles stabilized at roughly the same point. We are replacing the battery today in our 06 KJ and will post results in a few days.
Good questions. The fuel economy drop in the winter can drop significantly in the winter. We see a general decrease around 10%, but this can vary based on conditions. The fuel tends to be the largest factor. You might see an additional 5% drop if the vehicle is strictly a commuter due to having a cold start in the morning and a cold start returning home. The cold oil requires a few minutes to warm up. The lighter viscousity 0-W40 oil helps reduce the FE drop.

We are noticing that with the tune the warm-up is quicker with decent heat in cabin in about a 1/2 mile of city driving. The advanced timing helps transfer more heat to the coolant, should be directionally correct for improving the FE.

Fuel temps can effect efficiency, but it is usually not a big factor. Temps in the range of 30C to 50C at the engine fuel inlet are optimium, colder temps may have slightly more ignition delay and this will tend to drop the fuel economy. With the tune, the higher injeciton pressures help to increase the fuel temps in the common rail and minimize the ignition delay. The pressurizing of fuel in the rail can add between 30-70 C to the inlet fuel temps. The return fuel temps are also slightly higher to help warm the fuel in the tank faster.

The fuel heater has minimal impact on increasing the system temps. The injection system heat load is at least 100 times greater and probably more. We will instrument one of our KJs to see the temperature difference across the fuel heater and the return line to the tank. After a few weeks of monitoring we should have some hard numbers for you.
We are still going strong with the new torque converter offered through Mopar. It is a marked improvement over the stock units.

We have been testing it with our stage II turbo kit and the power delivery is phenomenal with the transmission in lock-up. At this point we are recommending the converter to all CRD owners that want to rid themselves of "shudder". It makes us shudder just thinking about failing a stock converter pulling a trailer up a mountain! It is well worth the cost to upgrade.
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