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Hi. My windshield wiper fluid nozzles are freezing. Past 2 MDXs never had this happen. I'm thinking it is a design defect. Argh. Too much money for this to be an issue.
Sorry to hear that... You may want to start a new thread, however, as this sentiment is not relevant to the current topic. :wink:
 

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It's not uncommon for the non-Hybrid MDX to go 10k before the MID runs down.
I actually inadvertently tested that on my (non-hybrid) 2014 MDX when the MID went to 0% on a coast to coast and back trip where I went over by about 200 miles. It ended up to be almost exactly 10,000 miles from the 100% to 0%. My assumption is that the type of oil (blend vs full syn) doesn't make a difference to the MID since I assume it's really based on easily attainable data points such as time at various RPMs, temperature, and the like and not on any kind of actual oil analysis. I had Mobile 1 full syn 0W-20 in it at the time. It appears from Elvis' post that the algorithm may have been tweaked for the hybrid or that maybe just the different ICE operating conditions caused it. Of course, the hybrid's 3.0 liter ICE is different than the 3.5 liter non-hybrid one which could also be a factor.
 

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My assumption is that the type of oil (blend vs full syn) doesn't make a difference to the MID.
Correct, the MID doesn't know what type of oil you use, and is conservative, by design.
 

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Correct, the MID doesn't know what type of oil you use, and is conservative, by design.
new to the sports hybrid family also and what I can say is this, there is definitely a learning curve with driving this vehicle with mpg and battery regeneration but it does get easier.Coming out of a 16 MDX Tech all I can say is this vehicle rides and handles a hell of a nicer.Not to mention also how smooth the 7 speed tranny is.Just saying
 

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Just replaced my 2015 MDX with a 2017 hybrid, Merry Christmas. Drove it on an 1800 mile trip that we just completed. Fuel economy is disappointing. I got 23.3 overall on the same trip that gave me over 25 with the 2015, numerous times. My average speed was about 80, same as always. Weather was bitter cold most of the way, but over-the-road fuel economy is likely not impacted by this. Car is new, but I don't put much stock in modern cars "loosening up" like used to be the case. I fear that it is what it is.

That's the bad news. The good news is that this vehicle is far better in every way than the 2015. Quieter, better handling, better ride, improved details - heck, even the range of the garage door opener is greatly improved. Hang the weaker fuel economy, this is a great car!
 

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The mileage will improve on a new car. Also,I don’t know what bitter cold is but,cold temperatures lower tire pressure. Lower tire pressure equals lower mileage. Also the car takes longer to warm up in cold weather. The heater is on more. Heated seats and wheel are probably on. Cold effects the battery. The extreme cold can have a lot of effect. Every accessory that’s on has an effect.
 

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Weather was bitter cold most of the way, but over-the-road fuel economy is likely not impacted by this.
It's likely you disproved this hypothesis.

This effect is well known by those of us who propel lightweight 2-wheeled contraptions with pitifully underpowered human engines. Air density is higher at lower temperatures, tire rubber hardens and becomes more resistant to deformation, bearings get tighter, grease hardens, yada yada yada.

As for internal combustion engines, they are less efficient if they aren't in their ideal operating temperature range. Even batteries aren't immune to Jack Frost's bite.

OTOH sustained 80 mph likely does have an impact, especially if there is unfavorable ambient wind. Crosswinds count.
 

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Bitter, as in -15 at times. I monitored tire pressure all the way and it was 35-36. On the trip in the opposite direction, a month ago, same roads, 2014 MDX, pressures were at 38. So, some difference, but not a lot. I haven't noticed any significant break-in effect in my cars in years. Back in the day, there was certainly a break-in effect, but I don't notice much of that with the modern engineering and materials and machining processes. The 2014 did better mpg than this, right from the start.

Yes, there is probably more rolling resistance in cold weather due to bearing friction with stiffer grease. Wind, which can be a major mpg factor and is often a factor in this trip, was remarkably tame in both directions this time. At the speeds we were traveling, speed *is* a big deal - slowing down to 70 makes the MID bar indicator improve visibly. But again, my comparison is to an equivalent speed with the 2014, not EPA. IC engines normally operate at a better thermal efficiency as air intake temperatures are reduced, although I cannot say how this one behaves.

So, yes, these sorts of things likely played a factor, but I am thinking that there is not enough to account for a near-10% reduction in mpg. But I hope you guys are right, and that things improve. Also, although we do the majority of our miles over-the-road, the hybrid really does make a noticeable difference around town, so overall fuel economy should be no worse than before.

In any event, I bought this car for performance/handling/ride improvements, not fuel economy, and I am delighted(!!) at how much better this vehicle is, compared to the 2014. I cannot believe how good this car feels for a 4500# behemouth. Also, I had the Technology package on the 2014. This one has the Advance package, and the added features are great. As one person here commented, "get the Advance package, it's the bee's knees". I was a bit skeptical at the time, as $6K is a lot of money. But the person who wrote this was right, at least for what I like. There were no Technology package hybrids available in my area and now I am happy that I didn't have the choice.

And the car is marginally quieter over the road than the 2014 - I wasn't expecting an improvement in this area - but my ears are sensitive to background noises, and this car is a bit better. Part could be tires, but not all.
 

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Another potential issue with high-speed driving is the limited rpm limit of the rear electric motors. This from a Car and Driver review:

"There are a couple of drawbacks, however. For all the NSX-derived wizardry, the system in the MDX Sport Hybrid isn’t really meant for high-speed driving. At 84 mph, just short of the rear motors’ 11,000-rpm redline, a one-way clutch decouples them from drive duty."

AFAIK this doesn't affect the front electric motor, but the battery pack may run out of juice under sustained load, and then you're just getting whatever economy the 3.0L ICE is capable of, and that doesn't have direct injection in the current MDX Sport Hybrid.
 

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Yes, at the cross-country speeds we drive, there is nothing going to the rear wheels. I didn't know what you are saying about the 3 liter engine. What you are suggesting could be the answer to the fuel economy question. You wouldn't know it but I have a couple of degrees in mechanical engineering and I know absolutely nothing about how this car works. Or any hybrid, for that matter, other than in a general sense. I heard about this car, drove it, fell in love with the performance, and bought it. Now I need to do two things: 1) figure out a way to get it out of my wife's hands now and then, grin, and 2) understand how it works so that I can fix it when it breaks. Do you know if Acura or another source has any sort of "theory of operation" literature where I can read about how they actually deliver power and charge the battery in the various modes of operation? The sales brochures don't provide any actual, technical insights on how this car works...
 

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Do you know if Acura or another source has any sort of "theory of operation" literature where I can read about how they actually deliver power and charge the battery in the various modes of operation?
Professor John D Kelly from Weber State University, Utah, has a YouTube channel that is truly fantastic. He has a multi-part series on the Honda IMA Hybrid system. The parts he demonstrates are not specific to the MDX -- but I believe the information he provides is excellent and representative of the patterns Honda engineering implements.

 

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As far as the 3.0 liter engine, the standard engine in 3rd-generation MDX ( 2014+ ) is a 3.5 liter direct-injected V6. The direct fuel injection contributes to improved fuel economy over intake plenum multi-port fuel injection or throttle-body fuel injection systems. For the MDX Sport Hybrid, Acura chose to use a 3.0 L V6 with multi-port fuel injection. The reasons for this are a matter of conjecture, but there is apparently a hefty tax on engines above 3.0 L in China. And one might speculate direct injection was dropped to partially offset the incremental cost of the hybrid hardware. In any case, during gasoline-only operation, the 3.0L V6 may be somewhat less efficient than the 3.5 L DI V6 engine. But this is purely speculation on my part.
 

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Thanks. I went through the two videos on the main battery unit. Kelly is very helpful. I then found his transaxle video, which is excellent. I now have a reasonable idea of how they do a generic hybrid. The MDX hybrid is different in that it has no driveshaft, no transaxle, and motors on the back wheels, but the idea has to be the same. Good to have rear motors and a tranny, as opposed to a transaxle, as the rear motors and torque vectoring seem to me like a huge performance edge. I would assume that the rear motors also become generators on braking, but I haven’t read that.

I have to think more about how this works in all of the various modes of operation, but the general idea is pretty simple. What I kept thinking about, as he dis-assembled part after part after part was, “Wow, what a lot of things to fail - components and connectors everywhere”. And air cooling seems to be to possibly be problematic, as he said that in the unit he was taking apart there was debris that would affect cooling (liquid cooling would have its own problems, too, but it might be more reliable?). So many parts and connections makes me think about getting an extended warranty, grin... Umm, no.

I see nothing about performing routine maintenance of any sort on the battery box, in spite of the fact that there was debris in the unit he was working on. Are there no filters that have to be replaced?

From a practical standpoint, I don’t know that I have enough experience to correctly diagnose electrical failures on a car like this. Unless the onboard diagnostics are complete and very specific, I just woudn’t have any confidence in getting the repair right.
 

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Oops, bad terminology. No transfer case. FWD only for the ICE. Does Acura call it a tranny or a transaxle on this car? I don’t know.
 

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Combo transmission w/differential = transaxle.
 

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Transmission issues?

I'm wondering if any others have had transmission problems. From the very beginning, my 2018 Hybrid has had a very slight shudder when pulling away from a stop. I thought it was the engine start up, but it wasn't, it occurred whether the engine shut down at a stop or not. (You can try this in Sport+ dynamic mode.) My Acura shop has replaced the transmission, and they tell me the shudder is gone, and I'm going to drive it today. The car has 2800 miles on it. And similar experiences, or is this a fluke?
 

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Yes, mine also. There is a TSB 19-004 which I'm having done next week. I hope that works.
They first did the TSB on mine, and it didn't work. Then they replaced the transmission. Do you drive in a lot of stop-and-go traffic? I ask, because I do, and have the unconfirmed idea that the two clutches in the transmission might not be able to tolerate the wear--though mine did it from the first day I drove the car with only a few miles on it.
 
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