Range Technology Beta Testing

[MNNJR69]

So....update after 1 week with the DFM module.

It definitely runs better off the line compared to running L9.

I had previously stated that the DFM does not activate with 0% throttle input and it doesn't SOMETIMES...The rest of the time when going downhill or braking or coasting it DOES....BUT it doesn't activate the DFM, rather the engine shuts off completely.

When I spoke to tech support about this, I was told the DFM does not activate, but rather the engine shuts down completely until the vehicle gets down to 3 to 5 mph or throttle input is recognized and then it restarts all 8 cylinders.

My concern is there any possible damage or wear to the engine or transmission while traveling down the freeway at 60 - 80 mph with the cruise control on and I come up on a vehicle going slower and the cruise control auto brakes to match the speed of the vehicle in front, It's sometimes shuts the engine off. Another condition is on a downhill slope and I have reached the set cruise speed, it will also shut the engine off until throttle input is recognized, at which time it restarts.

I'm assuming that is not good for any or all of the components. Such as would be in the case of towing a vehicle long distance without removing the drive shaft and disengaging the transmission. So for the meantime until I know more, on the streets I drive in L9 and then on the freeway in regular drive mode. I have tried to research the internet to find answers as to whether or not this is good or bad or indifferent, but did not come up with much.
Any comments or input is welcomed.

 

[DNZR2]

Just out of curiosity, have any of you geniuses actually confirmed the engine is shutting down by looking at the tach?

 

[boilerup]

Just out of curiosity, have any of you geniuses actually confirmed the engine is shutting down by looking at the tach?

I think what he means could just be fuel/spark cut? As long as the truck is in gear and the torque converter engaged tach should be reading any amount of rpms regardless of fuel/spark being present. Pretty sure the TCU doesn't really affect DFM or engine function but I could be very wrong

 

[44sixpack]

It may cut the fuel but the engine definitely doesn't shut down. who cares if the engine gets no fuel when it's on deceleration? unless you just enjoy going to the gas station.

 

[MNNJR69]

RPM still register, but absolutely no combustion. Problem is, if I shift to neutral will moving, the engine restarts or combustion starts again. Is the torque converter is still engaged and the camshaft is still spinning, then the pistons are still moving. Is the oil pump still running? Is it over lubricating?

 

[boilerup]

RPM still register, but absolutely no combustion. Problem is, if I shift to neutral will moving, the engine restarts or combustion starts again. Is the torque converter is still engaged and the camshaft is still spinning, then the pistons are still moving. Is the oil pump still running? Is it over lubricating?

The engine will always have a target rpm, shifting to neutral probably puts the target at whatever the idle rpm is set to so once it gets there spark and fuel will resume. Fuel cut and spark cut on decel has been a thing on cars for decades at this point and there is no departure from that, with or without DFM

Oil pump is driven from the rest of the rotating assembly so yes, if the engine is still spinning, oil is still flowing. There really is no such thing as over lubrication on a vehicle, everything can be a wear surface. The more you can lube it up to keep things from wearing the better

 

[44sixpack]

This series of engine has a front oil pump driven off the crank, it has a solenoid that opens a bypass lowering the oil pressure when the ECM tells it too. I have read, but have not confirmed the oil pump is in full pressure when in V8 mode.

I any event the engine is never without pressure while turning and there is no danger of over lubrication.

Cutting fuel on deceleration is a minor thing, but a good thing, it would be stupid to try to alter that.

 

[Waterdog]

@44sixpack, I have no worries. I was just pointing out something I’ve noticed in the fact it seems many of these detonate during road trips. If it happens it happens. Not much you can do about it.

I do think the oil pump cutting pressure is a bad idea. Why would you ever want that? Seems like a dumb idea to me.

 

[boilerup]

@44sixpack, I have no worries. I was just pointing out something I’ve noticed in the fact it seems many of these detonate during road trips. If it happens it happens. Not much you can do about it.

I do think the oil pump cutting pressure is a bad idea. Why would you ever want that? Seems like a dumb idea to me.

Most detonate during road trips because the (already bad) bearings get hot enough to micro weld to the crank/rods and spin, which causes the engine to seize. Like others have said the variable displacement pump shouldn't really be an issue if your truck isn't running with bad bearings. That design has been used for a while and has proven it isn't necessarily inherently bad. If you do have bad bearings, a pump running full displacement isn't going to prevent the engine from grenading anyway

 

[DNZR2]

It may cut the fuel but the engine definitely doesn't shut down. who cares if the engine gets no fuel when it's on deceleration? unless you just enjoy going to the gas station.

Apparently a lot of people care otherwise this would. be a dead post. As far as no fuel is concerned this is an issue but I won’t expand because you will only tell me I’m wrong.

 

[44sixpack]

I didn't say nobody cared, I said why would you care.

There is no reason to deliver fuel to an engine on compression. if you have a good reason then by all means do tell.

 

[DNZR2]

Right on que as expected ^^^^

 

[bobo57]

Can't imagine why lowering the volume more a lower rpms is good.

 

[boilerup]

Can't imagine why lowering the volume more a lower rpms is good.

Better Fuel Efficiency Through a Better <br>Oil Pump

Variable displacement oil pumps are seeing increased use in vehicles because of their benefits to fuel economy. They deliver oil to the engine at flow rates and pressures needed at the time, reducing

www.asme.org

Basically you make some trade offs, isn't necessarily good, but it also definitely isn't *bad*

 

[44sixpack]

Right on que as expected ^^^^

So you know why an engine needs fuel on deceleration , and it would seem it must be important. but you're going to keep it a secret . O'Tay.

 

[Byrds8]

Installed mine tonight. Didnt have to remove the wheel. Wont really get to try it out til tomorrow when I take the boys to school. I didnt hear a click when I plugged in the range but it didnt seem to want to come out either when I tried to wiggle it out. Here is to hoping its all the way in place lol.

Hope I never have to go down there and remove the damn thing though. I will assume that it will not interfere with a software upgrade etc when I take it in for the recall.

Update: after driving around some today, it is more responsive. However, I do not see the holding of gears longer or any difference in the oil pressure others have mentioned. When idling it still sits about 20-25 guessing by the dash. I do get the gurgle when coming to a stop which is ok. I also get the squeaking odd noise sometimes also. The same one that is there if DFM were active. Didn’t happen in L9. I don’t think I ever say someone say exactly what it is in any forum either. I do recall seeing a TSB with GM saying it’s “normal”. Guess I’ll live with it.

 

[Stretch1560z]

I have been monitoring this thread closely and my one observation is about leaving the range module on all the time. Its not like GM put the ECMs in a easily accessible place...aka under the hood...not that its horrible but really. My whole concern is repeated install/removal of the ecm connectors,possible pin damage on the ecm or module itself,the wheel well fasteners,and deforming of the wheel well liner. Its not like I'm going in there with with a 1/2"impact,hammer and prybar to remove this stuff but it is a sensitive piece of the vehicle that wasnt meant to be repeatedly worked on. Before anybody says "Well just dont buy it if your skeered"...I'm merely just asking the question and putting some food for thought out there. It would be informative to know if the module can be left on w/o any issues. Thanks and let the comments flow now.

 

[securityguy]

I have been monitoring this thread closely and my one observation is about leaving the range module on all the time. Its not like GM put the ECMs in a easily accessible place...aka under the hood...not that its horrible but really. My whole concern is repeated install/removal of the ecm connectors,possible pin damage on the ecm or module itself,the wheel well fasteners,and deforming of the wheel well liner. Its not like I'm going in there with with a 1/2"impact,hammer and prybar to remove this stuff but it is a sensitive piece of the vehicle that wasnt meant to be repeatedly worked on. Before anybody says "Well just dont buy it if your skeered"...I'm merely just asking the question and putting some food for thought out there. It would be informative to know if the module can be left on w/o any issues. Thanks and let the comments flow now.

It is designed to be left in once installed. No reason to pull it out unless you are having an ECU issue where they may need access to the ECU. Drive more...worry less!

 

[AXE]

I have been monitoring this thread closely and my one observation is about leaving the range module on all the time. Its not like GM put the ECMs in a easily accessible place...aka under the hood...not that its horrible but really. My whole concern is repeated install/removal of the ecm connectors,possible pin damage on the ecm or module itself,the wheel well fasteners,and deforming of the wheel well liner. Its not like I'm going in there with with a 1/2"impact,hammer and prybar to remove this stuff but it is a sensitive piece of the vehicle that wasnt meant to be repeatedly worked on. Before anybody says "Well just dont buy it if your skeered"...I'm merely just asking the question and putting some food for thought out there. It would be informative to know if the module can be left on w/o any issues. Thanks and let the comments flow now.

You don't need to pull it out ever, unless your having an issue.

If your worried about wheel well liner deformation, you can pull the whole liner and you only end up bending it a little along the outer edge of the wheel well liner. As for fasteners, these fasteners and speed nuts are available at automotive parts stores for low cost. I use a small low power electric screw driver that is very unlikely to strip a nut or thread. That being said, I've had a couple of the torx screw heads strip if they have some mud or debris in them and you don't get the bit seated deep enough.

However, if you're skeered, just don't buy one!

 

[AXE]

So here's some more data about 13 days post module install. I actually think this rig is getting better mileage by 1-1.5 mpg on the last 450+ miles. It's showing damn near 17 mpg and that's a very good mix of commuting in city traffic and freeway, rural interstate/highway, and a few short trips around the hood. The long term average I have tracking on Trip 2 shows 15.5 mpg.

My wife commented when I was taking this picture that the range showed over 400 miles when she fuled up the other day, said she's never seen that.

This rig ain't cutting fuel either, I can hear it running all the time.

We'll see how it goes, but it's certainly been an excellent experience so far.