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Messages posted by: GreenDieselEngineering
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This fueling issue has plagued several owners of the KJ CRD. These is not one specific cause, but rather system weaknesses that can add together to make the problem more pronounced. The P0093 occurs when the actual rail pressure cannot meet the desired set point for a certain time period. This flags a fault, causes limp-home mode and does not seem to recover unless the key is cycled. In many cases the ECU will just shut off the engine due to lack of fuel.

You should check the connector for the fuel heater on the fuel filter head assembly. The stock units tend to melt around the terminals that are built into the fuel assy. We would recommend filling the connector cavity with silicon sealant or purchasing a new filter head and wiring kit for the fuel heater (TSB 18-011-09, new part number 68043089AA is for fuel water separator assy). If you suspect a vacuum leak in the fuel system this would be the first place to address the issue.

The diagnostic limits might be a tad to tight for the fuel system, we are opening them up with the GDE tune to minimize the potential for this issue and setting a CEL if the issue occurs, no more engine shut-off without a CEL for fuel system. We would agree that the engine reaction to less than adequate fuel is no aggressive and the vehicle should never shut off on its own.
We intend on having reliability with the turbo kit...as for now, we are making trips with spare hardware just in case

We are planning a towing trip out west with a 3000-4000 lb. trailer with the turbo in early September. This will allow us to dial in all the safeties.

Have you noticed any drive ability issues with the KJ? The first trailer tow up a grade at 1700rpm in 3rd lock-up will let you know how strong your current TC is. If it shudders as you load the throttle to just below any downshift point, then you may want to push toward an upgrade. The ECO tune helps to minimize the initiation of shudder through torque management in lock-up, a good safety for the interim.

The ESP on the 06 model does very well in bad conditions in the mountains...is the vehicle already set-up with trailer brakes? A good investment if the vehicle will be towing often. The KJ can be a great long term vehicle...good purchase!
All the tunes and kits from GDE will pass the yearly or bi-yearly emission tests that some states enforce. These are rudimentary tests used to do basic checks on the vehicles to ensure they are running in normal condition, i.e. there must not be a CEL on or the vehicle fails. One additional test for diesels in some states is a free acceleration in park or neutral, here they are looking for normal levles of smoke (particulates). All our tunes have lower smoke than production in this operating zone. Additionally, there will be no CEL with our tunes as long as all the sensors/wiring is plugged in like a stock vehicle.

There are other emission tests that OEMs (original equipment manufacturers) must perform, i.e. FTP75, US06 and SC03. These require million $+ facilities to even perform the testing and cost a small fortune. These are used as a basis for selling vehicles in the states mandated by the federal government. In-use testing is based on each state's requirements for individual owners and never involves such invovled testing like the federal government.
It is very typical for after market products to stipulate "for off-road use only". This is a caveat in the US emission laws that allows performance products to be sold in the US. The disclaimer is to reduce the cost of bringing products to market without requiring full blown emission compliance. This puts the responsibility in the hands of the consumer. For instance, if one buys a performance muffler many times it will have the same disclaimer, and ususally means no emission testing was performed in developing the product due to the high cost associated with it. It does not necessarily mean the product is bad for pollution, but rather never tested.

Before circa 1970 the US did not have much in terms of emission laws from motor vehicles, since the clean air act we have been progressively reducing the emissions of motor vehicles minus greenhouse gas emissions (CO2). The US pumps as much greenhouse gas as it wants at the current moment fo rthe most part. New laws have recently been enacted to curb our CO2 production including the cap and trade program for plants and higher corporate average fuel economy (CAFE) for motor vehicles. Diesels are naturally lower in CO2 production by about 30% versus a similar sized gasoline counterpart.
Check under "faq" and "engine performance" inside the forum, it shows the torque and horsepower graphs for all the tunes vs. stock. However, the graphs can't tell the full story. The turbo shines in city driving, the response is much quicker than stock. You find that there is always more pedal than what you need. On the highway, the passing performance is linear...from 60 to well past any legal speed...less the autobahn! In cruise, the turbo has slightly less restriction, so this helps with fuel economy.

The lack of warranty may be an issue for some, but the vehicle in general is out of warranty. The turbo kit is an aftermarket option for people that want to see what the CRD is fully capable of. We are keeping the design limitations in check, however the driveline was never tested to this extreme. The fact that it has survived the flogging thus far is a testament to the 45RFE! We are still running the stock TC, so we have not fully unleashed the torque from 1600-2200 rpm. This is the most efficient SUV on the road today! Try to pull a 3000lb. trailer with an Escape hybrid...not even the same sport!
Here are out goals for the Stage II turbo kit:
1. increased power/torque, linear power delivery
2. slightly improved fuel economy in steady state driving
3. similar longevity to stock turbo

We have been running the turbo in one vehicle for about 6 weeks. The development is progressing well and we are running the vehicle very hard to simulate a durability cycle. We are planning a cross country towing validation trip in a couple weeks. There is no plan to release this product until we have a solid confidence in its reliability. The manufacturer will not provide a product warranty for the new turbo as we have to perform some machining operations and weld new flanges on for mounting and support reasons. The volumes are not high enough for the turbo manufacturer to have a unique design to fit our KJs without mods. Changing the tooling could run into the millions on a turbocharger.

The tune will ensure the new turbo functions within all its design limits in any ambient temp and altitude. Our company goal is to build a good reputation for providing well engineered solutions, releasing a product with potential issues is not part of that strategy. We want to tune every diesel available in the US long term, the KJ is the first.

You have several good questions, sounds like you have had some issues with previous tunes. What is the RC1 tune? Is this an ECU reprogram or a chip that is installed in the vehicle? You should never have a run away condition unless the RC1 tune confused the ECU or there is a wiring issue in the vehicle, either case is not a good situation to be faced with.

1. The OEM injectors have enough flow capability to provide the proper fueling for the hot tune and also for the turbo kit. The duration of injection is about 20% longer and we advance the main injection timing to compensate for the longer injection.

2. The exhaust flange and downpipe are stainless steel and the same diameter as the OEM pipe (2.5")

3. Both our test mules are using the stock exhaust configuration...catalyst, muffler, etc. The backpressure on this vehicle is sufficiently low that we could not justify the expense of aftermarket exhaust and removing the catalyst makes the exhaust smell bad.

4. The vehicle with turbo kit just got a set of Samcos installed yesterday. We blew the CAC hose that goes from intercooler to the engine inlet (same failure location as most customers). This turbo runs substantially higher boost during hard accels. We will have an update on Samco durability in a month or two.

5. Both tunes turn off the EGR diagnostics to prevent CEL and the system is not used.

6. There is no additional benefit to installing the SEGR, no flow through the circuit with or without SEGR.

7. We are not running a boost valve with this application. The variable geometry turbo does not require a boost valve. The vanes automatically open based on boost pressure, if an overboost were to occur in a transient situation the governors will open the vanes more to bleed off boost. It is like having a boost valve built in, but one that is actively governing all the time. Only if the turbo vanes are stuck will an overboost potentially cause issues. This is a very rare issue with these types of turbos. Vane sticking occurs with soot buildup in turbine over time. As long as one loads the engine from time to time (leads to full vane movement...self cleaning) there should not be an issue. Constant steady-state driving where the vanes are always in the same position may allow for soot buildup. This is more of an issue in the stock situation, with the tune the soot formation is much less as the combustion is more efficient.

8. The cruise control functions correctly with hot tune or turbo kit. We made the cruise slightly less agressive than stock, this means slightly more speed variation around the set point speed (+/- 1.5 mph in hills), but also provides a 3% improvement in fuel economy while cruise is engaged.

9. We have never had an uncontrolled acceleration with any tune developed and no current customers have commented on unwarranted accelerations. This could be a vehicle wiring issue or something going on with the tune you currently have.

We hope this provides the information you are looking for. Please let us know if you have any additional questions or comments.

We are able to set-up clone ECUs if the customer wishes to have a spare module. We can program the VIN and injector codes as provided by the customer. The injector codes are located in two places, first, on the front of the engine timing cover (just behind the mechanical fan) there is a bar code with 24 alphanumeric digits, this is the injector code. Otherwise, one can remove the engine cover and read off each individual injector code from the top of each injector (a 6 digit code on the front,top of injector). May want to check the injectors just in case one or more have been replaced during the life of the vehicle.

It is important to note that the ECUs from 2005 and 2006 are not compatible due to differences in software and vehicle electronics communication. A clone ECU must be from the same model year application.
For validation testing we install the EGT approximately 6 inches after the turbo outlet flange in the exhaust downpipe. We also install an EGT upstream of the turbo in the exhaust manifold for correlation. The temperature drop across the turbo between the two thermocouples is about 180 F (100 C) while testing peak power. For customer vehicles we recommend installing one EGT downstream of the turbo in the exhaust system, this is much easier to install and there is no need to worry about metal shavings with tapping the pipe. As long as the EGTs after the turbo stay below 700 C (1292 F) the system is working properly.

The turbo speed sensor is not necessary for anything other than development. Turbo speed follows boost pressure in a linear reletationship. We install speed sensors to allow us to calibrate the maximum boost pressure allowable in any given operating range. We then perform corrections to the boost set point in high altitude conditions as the turbo spins faster, we need to ensure the turbo speeds will not increase past the limits of the bearing system inside the turbo. After this work is completed a speed sensor is just a very expensive gauge to look at once in a while for fun.

A boost gauge is not needed, but it is also neat to watch. It should be tapped into the intake manifold somewhere if so desired.
How fast were you going up the grade and what did you slow down to? Were you wide open throttle? With a 5000 lb trailer at 110 F we targeted runs at 55mph and settled in around 42-45mph up Baker grade. With a 3000 lb unit you should be able to hold 55 (we just push it to the floor with AC on until it shuts off on its own and keep going, the speed will gradually slow down until stabilization is found). Sometimes the trans will downshift to 2nd' if speed drops too much (used only during towing), it should pick up speed in that gear or maintain. With 3000lb or more we would recommend O/D off driving if the transmission keeps shifting up and down, 3rd lock-up keeps the mechanical fan spinning at the optimum speed for air flow through the cooling stack operating in high ambient temp/altitude conditions. Do you use trailer brakes? Definitely recommended on the KJ to help keep the best stability.

With a beefed up torque converter and tune to hold lock-up at peak torque, it might be possible to hold more grades in 4th or 5th lock-up in normal towing. This would improve fuel economy and ride smoother.

The target price is holding at $2500 based on the machining and parts cost. Our plan is to build in batches of 10 with first product available in the October timeframe. We will take reserves through email. If the interest is high we will try to increase the batch size to find any cost reduction feasible.

A 420 mile trip this weekend in 85-90 F temp, AC on, running 75-80mph with 30 miles at 45mph city driving produced 26.4 mpg. There were plenty of hard accels to exercise the foot and heart!
If the vehicle is functioning correctly there is no need for a lift pump. Our vehicles have been updated with the new fuel filter head assembly that fixes the fuel heater circuit wiring issue so the system will not pull air through the filter unit. It is important to change the fuel filter as recommended in the service manual to prevent a large pressure drop across the filter unit.

If one is having issues with hard starting, or engine shut-off due to fuel starvation there is a leak in the fuel system somewhere. We would recommend root causing the leak, but a lift pump would also address the issue. Our concern with the lift pump is having positive pressure on a fuel system that could possibly have a leak, there is a possibility that the pump could push fuel out the leak path onto the ground or in the engine compartment...this could lead to a potential fire hazard. The lift pump should be very low pressure, 2-4 psi would be plenty.

The system was designed not to need the lift pump, but the system also has potential for leaks so this is catch 22 and requires preventative maintenance.
The tune has several features that benefit towing situations. Here is a breakdown of what we have incorporated into the product:

1. Advanced injection timing and higher boost improves towing fuel economy in any gear, this also keeps the exhaust temps lower.
2. Engine torque limit while the transmission is in lock-up mode to minimize the possiblity of initiating "shudder" in the torque converter. This helps to prolong the life of the TC.
3. The electric fan is turned on when the transmission fluid is above normal operating temps when towing. The top three rows of the trans cooler are exposed to the electric fan in the cooling pack and we modified the tune to activate the fan based on trans fluid temp. This is not active in the production calibration.

Honestly, you do not have to be concerned when the coolant gauge starts to rise, only when it is in the red zone do you need to back off the throttle. The engine is self limiting based on coolant temp. The AC will automatically shut off when the heat load is too great. Check out our coolant gauge temperature breakdown on this forum for the 2005 and 2006 clusters.

We could change the the coolant gauge output that is displayed on the cluster to always point in the middle safe zone unless there is an emminant problem. We have not done this and want to gauge what the owners would prefer. If the gauge is moving toward the red zone when the engine is still in normal conditions it does not make much sense and only leads to unwarranted concern by the driver. What is your opinion about this option?
A fuel cooler is not necessary on the KJ CRD. The temps rarely get over 130 F and only in low fuel level situations. Towing a 5000lb trailer with low fuel one can see up to 175 F with less than two gallons remaining in the tank...ie. with low fuel light on. Not something most people would ever consider doing. A fuel limitation starts around 160 F and progesses up to 195 F at which time the engine will only idle. We have never seen temps near this high.

A fuel cooler can be a drawback if living in cold climates, there is more potential for line freeze with a cooler and the fuel heater on the vehicle does nothing for frozen fuel lines near the tank.

The improved coastdown goes help with MPG, but the diesel still has more inherent engine braking than a gas job due to the 17.5 to 1 compression ratio. Definitely understand your point about mountain driving, during testing we have cranked up the boost at zero throttle going downhill by closing the turbo vanes and the engine braking almost doubled...it would be a very nice feature for mountain driving with a trailer. We are investigating having minimal engine braking in 4th and 5th gears, but having higher engine braking in 3rd gear (when the O/D off button is engaged)...typical only used when trailer towing. If you want a specific setting in the tune we can always set it for your preference.
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