[yennes]

Now that ski season has started I am driving the van more in the mountains I tend to coast down from the ski hill and noticed that the transmission is very "uncomfortable" if the rev match is not very close shifting back into drive. I also notice that coasting in gear is not possible as the torque converter stays locked up in 6th so you get engine braking, even in top gear. My Ford Flex is completely different, I can shift from neutral to drive with any drama and it "coasts" in gear without engine braking. Does this bother anybody else?

 

[uncubed]

Get use to it. Engine braking is the norm. In the manual somewhere it says do not put in
neutral for coasting. This is not good for the transmission. I have had the engine up to
4500 rpms all by itself by engine braking going down hills in the mountains. Nothing I
can do. Just go along for the ride.

 

[keeponvaning]

Agreed !

 

[Zoomyn]

Looking forward to getting better acquainted with* unwanted engine braking with my diesel this Minnesota winter, yanno, the old back end passing the front schtick...

 

[RDinNHandAZ]

With the diesel it will down shift downhill and if you touch the brakes the downshift is apt to be more than one gear if you are going a moderate speed. I don't like it so in those coasting moments I just go over to "M" and it stays in high down to about 40 mph even with the brakes on. Another advantage for the diesel. Many times the downshift is ok and anticipates what I would do and that is fine, but I have the option.

 

[Chance]

...cut....

I also notice that coasting in gear is not possible as the torque converter stays locked up in 6th so you get engine braking, even in top gear.

....cut....

Every time this subject comes up I get confused regarding what ProMasters do that makes drivers want to take them out of gear on downhills.

If the driver wants to hold the same speed, and engine braking is required according to computer to hold that speed, what is option to engine braking -- to ride brakes?

And if driver wants to go faster down the hill, as if in neutral and accelerating downhill like a soap box derby car, then why not step on gas a little until ProMaster accelerates at desired rate?

Obviously between these two extremes there must be a middle ground where the PM does something very unusual that drivers like me, who haven't experienced this issue firsthand, have a hard time relating why it's a problem.

I wish the PM downshifting weirdness was something that could be described in a way that was easier to understand. I don't doubt it's real, otherwise it wouldn't keep coming up.

 

[RDinNHandAZ]

It used to be that if the car coasted in high gear it used very little fuel, not none but not much. If you shifted down the vehicle used MORE fuel so car makers left the transmission in high and let you coast. In the 1980's when fuel injection became common it was realized that during coasting the computer could reduce the fuel consumed to ZERO. Shifting down also cost no fuel. Some engineer decided to put into the program a downshift and get the advantage of less braking and less freewheeling down hills. To those of us used to coasting it feels weird! Wrong! Younger drivers have had it so it seems normal, as well as some who are oblivious and should not be given a tachometer (that funny gauge on the right that goes up and down for some unknown reason.) I HATE it and am looking forward to a time we have the ability to modify the computer to customize such things, .... uh that will be never!

 

[Chance]

....cut.... Shifting down also cost no fuel. Some engineer decided to put into the program a downshift and get the advantage of less braking and less freewheeling down hills. To those of us used to coasting it feels weird! Wrong! ....cut....

I grew up driving stick shifts -- from sports cars to trucks -- and still don't understand why it's an issue. It sounds like what most are calling coasting or freewheeling (a bike term) is the equivalent of putting your manual transmission in neutral and letting the car "coast" down a hill. But how often is that useful?

Using that definition as a point of reference, what does a PM automatic transmission do that is so bad?

As an example, if I were driving my stickshift Mustang on the Interstate, and was headed down a grade where I could put it in neutral, what would happen? If the grade is too steep it may try to go 80~90 MPH when I may want to limit it to 70 MPH. That would require some level of engine braking (maybe top gear or maybe lower gear).

If the grade is not steep enough, and the car would only coast downhill at 50 MPH, then I'd have to put the transmission in gear and give it a little gas to hold the desired 70 MPH.

The third condition is that of the grade being just the right slope to provide coasting at the desired 70 MPH. In that case I can roll down the hill at 70 MPH with transmission in neutral and engine at +/- 600 RPM. But how often does this actually happen? Rarely for me. I either want to go faster in gear with a little gas, or want to go slower and hence use whatever gear is right to slow me down using engine braking.

Even when speed is just right (rarely the case), fuel savings versus leaving the car in top gear with a tiny amount of pressure on gas pedal is insignificant. Plus having the car in gear is preferable anyway from a safety standpoint.

I still don't get what the PM does that is so objectionable.

 

[myke]

It sounds like what most are calling coasting or freewheeling (a bike term) is the equivalent of putting your manual transmission in neutral and letting the car "coast" down a hill. But how often is that useful?

I've been doing that in honda accord (5 speed manual) on every down hill for the past 10 years. It's awesome, I get 35 mpg around town.

 

[Chance]

I've been doing that in honda accord (5 speed manual) on every down hill for the past 10 years. It's awesome, I get 35 mpg around town.

Awesome? (Rhetorical question)

For me it depends on what your MPG would be if driving normal. If 30 MPG then it's worth something, but if 34.9 MPG would you still do it? I wouldn't.

Driving downhill uses so little gas that I doubt it would make much difference. I had a car with instantaneous MPG display and when going downhill with foot mostly off accelerator it would peg at 99 MPG. Compared to my typical average, there wouldn't have been enough downhills even if MPG went to infinity (i.e. -- zero gas consumption) to affect the total enough for me to worry about.

I do care about fuel economy, but focus on other things with higher return. But that's just me. I respect whatever others want to do as long as it doesn't affect safety of others.

 

[MsNomer]

"I had a car with instantaneous MPG display and when going downhill with foot mostly off accelerator it would peg at 99 MPG."

My PM gasser will do the same thing if the incline isn't too steep.

 

[Ghosting]

When I was in college I had a manual honda civic that I would often "coast" down hills in. I would often cross the Cascade Mountains, and (particularly going west) it make a big difference in fuel economy. I can't remember the specific numbers now (that was almost 30 years ago), but I know that coming down Snoqualmie Pass, I would even shut off the motor (no power steering or brakes) for more than five miles.

It would be interesting to know specifically how the ProMaster handles it when you don't need power to the motor. I assume it does something smart... but what exactly?

 

[Roblee]

My most memorable "driving" experience was 1970 in Death Valley NP birding and photographing wildflowers. Going to Bad Water at -282'. Tied side doors of '66 VW bus open, all windows open, in neutral and engine off. The coast was maybe 25 miles? Slight decline so speed never over 50 or so. It was a sweet fun ride.

Fast forward to Big Bend NP last week. Used manual mode going in and out of the Basin. Can shift down to second gear but not first. I would have liked first gear for a couple of short runs. I like the manual mode. Works just like my old stick shifts; just no clutch and no first gear. Didn't try any coasting.

 

[Brian P]

When I was in college I had a manual honda civic that I would often "coast" down hills in. I would often cross the Cascade Mountains, and (particularly going west) it make a big difference in fuel economy. I can't remember the specific numbers now (that was almost 30 years ago), but I know that coming down Snoqualmie Pass, I would even shut off the motor (no power steering or brakes) for more than five miles.

It would be interesting to know specifically how the ProMaster handles it when you don't need power to the motor. I assume it does something smart... but what exactly?

Modern fuel injected engines switch off fuel to the injectors when the drivetrain is back-driving the engine (coasting in gear). In some cases they maintain a tiny bit of fuel delivery in order to keep the catalytic converter above a certain minimum temperature to avoid an emissions spike when the engine eventually takes up the load again.

As for the thing that drives people nuts when coasting ... The issue is that if you WANT to use a downhill to speed up, it won't let you. I'm pretty sure the logic is something like this. It memorizes the road speed at which your foot came completely off the accelerator pedal. If that speed is exceeded by a certain threshold (indicating coasting down a hill) it downshifts to increase engine braking. If speed fails to come down (indicating coasting down a steep hill) it downshifts again.

You can likely blame this on people who don't know to downshift manually on steep downhills leading to situations where the vehicle "runs away" (perception) or where people smoke their brakes because they end up using the brakes too much rather than engine braking.

I consider the inability to use a downhill to accelerate by coasting to be a minor irritant. I'd be happier if there were some way to override it (e.g. switching to manual mode actually stopped this from happening). But it's not a deal breaker ...

 

[Chance]

Modern fuel injected engines switch off fuel to the injectors when the drivetrain is back-driving the engine (coasting in gear). In some cases they maintain a tiny bit of fuel delivery in order to keep the catalytic converter above a certain minimum temperature to avoid an emissions spike when the engine eventually takes up the load again.

As for the thing that drives people nuts when coasting ... The issue is that if you WANT to use a downhill to speed up, it won't let you. I'm pretty sure the logic is something like this. It memorizes the road speed at which your foot came completely off the accelerator pedal. If that speed is exceeded by a certain threshold (indicating coasting down a hill) it downshifts to increase engine braking. If speed fails to come down (indicating coasting down a steep hill) it downshifts again.

You can likely blame this on people who don't know to downshift manually on steep downhills leading to situations where the vehicle "runs away" (perception) or where people smoke their brakes because they end up using the brakes too much rather than engine braking.

I consider the inability to use a downhill to accelerate by coasting to be a minor irritant. I'd be happier if there were some way to override it (e.g. switching to manual mode actually stopped this from happening). But it's not a deal breaker ...

Are you saying that once the driver lifts his foot off accelerator on a downhill, that he can't change his mind and step on it again to start accelerating down the hill? It's hard to imagine it won't let the driver reset the desired speed down the hill.

I think I get what you're stating, but if all the driver has to do is give it a little gas to go faster, then I agree it's no more than a minor irritant.

 

[Brian P]

Sure you can speed up down a hill by applying accelerator pedal. But watch the fuel consumption display when you do this. I could use some downhills to accelerate from (let's say) 60 to 80 km/h while using ZERO fuel if I could force the transmission to stay in top gear. But as it stands, you can't do that.

 

[wincrasher]

Maybe it's just my imagination, but I've found with the cruise control on, this speed holding and downshifting is more pronounced. With it off, it seems to have more latitude to accelerate and freewheel.

 

[makevx73]

Maybe it's just my imagination, but I've found with the cruise control on, this speed holding and downshifting is more pronounced. With it off, it seems to have more latitude to accelerate and freewheel.

I agree with you on this. Both up hill and downhill. I find I hardly use the cruise control at all unless the road is nearly flat. I've had several experiences, on little rolling hills, where it downshifted and rev'd pretty high while going downhill for no reason. Didn't like that at all...

 

[bikerider]

And if driver wants to go faster down the hill, as if in neutral and accelerating downhill like a soap box derby car, then why not step on gas a little until ProMaster accelerates at desired rate?

I bought a PM with its measly V-6 like with my old underpowered V-6 E150, to save on fuel costs. Doesn't it make sense therefore, that I'm inclined to coast down hills to maximize MPG as well so I don't want to step on the gas.

But here's the concern I have in this area that I have yet to get a definitive answer to. Doesn't downshifting rather than coasting increase drivetrain wear, costing much more than a brake job? (With both costing more than my approach of cresting the mountain slower and hitting the bottom faster.

 

[Swoop]

Sure you can speed up down a hill by applying accelerator pedal. But watch the fuel consumption display when you do this. I could use some downhills to accelerate from (let's say) 60 to 80 km/h while using ZERO fuel if I could force the transmission to stay in top gear. But as it stands, you can't do that.

In my experience, if I keep my foot very lightly on the accelerator while descending, the transmission stays in 6th gear. The instant mpg read-out floats around in the 70-99.9 range. That seems fine to me. If the hill is steep, I have no objection to engine braking. When I am in light traffic, I try to crest hills at ~60mph and start climbing the next one at ~70mph, to use momentum to maximize mpg.