Struggling going uphill in Rockies Colorado

your hybrid battery could be on the way out. how many miles on her? can you hear the cooling fan in the back louder than normal? it's also possible that your battery is overheating, and protecting itself.

 

Thin air, and hilly terrain? Maybe your knock sensor is retarding your ignition timing causing even lower power?

Try putting some premium gas in the tank to mix with the low octane stuff that's already in there. That should help with the power loss slightly.

SCH-I535

 

What alternative do you have if you don't continue to drive the car? Obviously your car is being stressed with the mountainous terrain.

Have you checked the engine oil level and engine coolant level in the radiator, recently? For that matter all engine compartment fluids should be checked while you are at it.
What fuel octane are you using?

With at least 250K miles logged, who knows what condition the engine is in. It also sounds like your traction battery may be about to die. There is no telling if both will last, but it is too late for you to be asking about that when you are already enroute.

 

A possible way to "slow down" the damage is to adopt what truck drivers do when driving the mountains. They drive on the right lane and slow down to not overtax their engine or because the truck's not capable of it. It also saves your gas mpg. It can be frustrating but it'll be easier on your engine and battery due to the lower overall load and rpm. I've seen them climb at 35-45 in a 65 zone.

 

I would make sure all your engine fluids are at the correct level and continue driving. Climbing Hills is not a strong point with the prius.

 

My Prius will drain the battery pretty quick going uphill, especially if the AC is on, too. Its never had a problem maintaining at least the speed limit (up to 75MPH on some of them) up some pretty good hills, even with the battery down to 1 or 2 bars.
You could have a problem, but without any lights on or codes, I think you're just experiencing hills.

 

If you have a half tank or less of gas, fill the tank with 92 octane premium. If almost full tank, put in a bottle of name brand octane booster.

SCH-I535

 

We vacationed in the Glacier/Yellowstone area last year in our 2006. There were several places where the engine was working hard, and several places where the traction battery dropped so low that I had to slow down. Long uphill pulls with a heavily loaded vehicle at altitude are hard work. The performance drops off when you get to zero purple bars... I just moved to the right lane with the trucks and matched their speed until the battery caught up.

I agree that you should verify that all the fluids are correct, but it may just be that you're testing the limits of Gen2 power. There's a reason the Gen3 has a larger engine, and I think you've found it...

 

Could you better describe how the car is 'struggling'?

Many people in the latest generation have driven only 21st Century cars (or mid-1990s onward) made after the horsepower wars of the cheap fuel era. Many of them would describe the perfectly normal hill climbing behavior of 2-digit horsepower engines that were common in the 1970s and 1980s as 'struggling'. Your GenII Prius has only 78 horsepower after the battery is depleted. That depletion will occur quickly, long before you reach the top of many Rockies passes.

Some GenII owners here have always complained about hill climbing in the Rockies. But some others who live there seem to have no real problem, though they also know what to expect, how to deal with it, and don't expect the car to act like 150+HP models.

My more powerful GenIII sounds loud when climbing, even when its RPM is actually lower than my more powerful Subaru on moderate hills. (The high Suby RPM is forced by its uneconomical gear ratios.) Of course, for the steeper hills, my Prius must crank up significantly higher RPM and more noise, but it still climbs fine.

A few more hints could help separate actual car problems from possibly normal but unfamiliar small-engine car behavior.

While Yellowstone NP is at high elevation, most slopes should be less steep and highway speeds significantly lower, so it should be less of a challenge than climbing Colorado's Vail Pass. Banff and Jasper Parks should be somewhat easier still.

If your problems are directly related to elevation, then I'm suspicious that may be just your expectations and/or driving style with the small engine at high altitude in thin air. The engine will adjust just fine to the thin air, it just can't produce as much power up there. If the problem relates more to hill steepness, regardless of altitude (sea level as well as high Colorado), then my suspicions would lean more towards the car.

 

PriusEnt,

I for one think your Prius is showing it's age. I would NOT abandon it for a rental car. I would monitor fluid levels, add some octane booster to the fuel, and slow down a little. Don't push the Prius too hard going up those hills. Stay in the right hand lane, and take your time. The slower you go, the better it is for the Prius. No sense in overworking it in those mountains. Remember the ICE does not have a lot of horse power. Once the traction battery drops down to 1 or 2 purple/red bars, the assist is pretty much gone. The only other choice would be to pull over to the side, do a force charge, and then continue on. But force charging waste's fuel, and does heat up the MG's doing it. They are going to be hot anyway from the hill climbing. So when you put it all together, the answer is to slow down, take your time. As long as the battery does not overheat, you should be Ok. Now if you start getting lights on the dash, then it is a different story. Finish up the trip, then think about how much longer you intend to keep the Prius. If a long time, you might consider a rebuild on the battery pack.

Have a nice trip!

Ron (dorunron)

 

I'm wondering if it is not simply the engine revving to get over the hills as it is intended to do. Our family of four did a cross-country road trip in our '04 back in '07. We were loaded with all the camping gear, roof rack, etc. I got a ScanGauge specifically to watch the coolant temp and rpm's. It did fine, but did sound like the engine was screaming at times going over various passes, etc. We backed the speed down at times on those steep upgrades. Ours turned over 200,000 miles last week and is still running fine.

PA P

 

I personally don't think you need octane booster. The lower air pressure at higher elevations actually lets you run lower octane in a given engine (which is why regular is 87 octane at lower elevations but 85 octane at higher elevations). If you still want to boost the octane, just fill with premium next time or now if you have less than half a tank.

 

vskid is correct. If you fill with Premium, you won't need the octane booster. Any brand of the booster will work fine. Figure out the cost difference and then decide what you are going to do...

Take it easy and enjoy the trip and the scenery.

Ron

 

Alright, I am late to the party, but the moral is don't freak out. The Rockies are some of the most stressful roads in America. That portion of I-70 has the steepest grade of any interstate within the country. You are running at high elevation, sometimes above 10,000ft where the air is thin meaning your meagre little engine has even less power.

No need for octane boost or any of that. Just drive it. The Prius in the mountains should actually be run on lower octane fuel. If you fuel up in Summit county area, it is not unlikely to see 83 octane which the Prius loves at that elevation. Once you get to Denver or Colorado Springs, you are still at 5000-7000ft above sea level and 85octane is common low grade that the Prius takes.

It sounds like you have never driven the Prius in the Rockies, but what you describe is normal. Shortly up the ascent the battery will become completely depleted and you will be running on the gas engine's output only. It will get loud and rev at high RPMs to maintain speed. If you let off the gas for any reason, you will not regain that speed when you reapply your foot to the floor and the engine will work just as hard as before. In the Prius, all of the roads should be traverseable at the PSL as long as you start the bottom at that speed and hold the pedal to the floor. Any let up, for any reason, and you will lose a few MPH's and not get them back until you reach a downward or semi-flat slope.

Just drive it and don't worry. Your Prius is acting normal for the abuse of the mountains.

 

FWIW, here's what I do in our '05 when driving up north into the mountains.

- When climbing bring up the "energy" display that shows the arrows going in and out of the battery.
- Find the point on the accelerator where you are maintaining speed on the hill.
- Adjust the accelerator position slightly until the energy display show no arrows into or out of the battery. (Note this can be from either lifting up a little on the accelerator, or from pushing it a little harder. If its floored though, there's only one way to go).

I've actually been really impressed with the hill climbing ability of the Gen 2. The problem IMHO is that it does take some driver participation to avoid depleting the battery. Once you have driven it down to 1-2 bars, its game over. Now you are not only on ICE power only, but are sapping more power off the ICE to bring the battery SOC back up.

By being mindful about what the battery is doing when you are climbing, I've found I can routinely climb long 7-8% grades at 65-75mph without dropping any bars off the battery. This is extra handy, because if you do have to slow down waiting for an opportunity to pass a truck or something, I've found that by maintain a fullish battery the Gen 2 even has plenty of power to get back up to these speeds from 35mph or under on these sorts of grades. This does mean flooring it and using battery and the engine will be at max rpm and sounds like its going to explode, but its really fine As long as you don't over do it and drain the battery you'll still be fine. In fact, I've often found that after one of these acceleration bursts you can find a pedal position that still maintains 65-75mph and puts some charge back into the battery while you continue to climb, just in case you have to pass again.

 

You cannot climb 8% grades at 65mph without flow of the battery and maintain speed. I drive the mountains at least twice a week. In the winter which is coming here soon, sometimes 4-6 times per week I am making the journey to get some powder. Reminds me, I need to finalize my season pass!