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2013 Hyundai Elantra Limited
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Discussion Starter #1
Car has about 96,000 miles on it. If it's got a tranny problem I want to get it fixed before I hit the end of the warranty. Engine was already replaced at 88K miles under warranty by the previous owner, I got it at 95,000 miles. I've put an oil change and brake pads + rotors all the way around. Other than that it seems to be fine except really lousy gas mileage (25MPG, my wife can hit 30 but she works right off the Interstate and I have to drive in town for 10 minutes after the Interstate trip when I work) and now this issue that I've noticed.

Basically, I'm going about 72 MPH, tach is at 2,300 RPM, and I select manual shifting - gear 6 to hold it in 6 on a hill. The engine doesn't bog down, it does lose maybe 1 or 2 MPH from the cruise setting, but what concerns me is the RPMS jump 500 to 2,800. At first I thought it had overridden the manual gear selection, but when I popped the shifter down to 5 to check, actually shifting to 5th adds another 500 RPM for 3,300.

Now here's the kicker: if I'm in a selected gear 6, and the RPM jumps, and then I switch it back to auto gear select / D, the RPMs drop back down where they belong at that speed and gear, 2,300 (unless the incline is steep enough for it to select 5th, in which case they go up of course).

As well, at about 40 MPH selected gear 5, if I hit the gas the RPMs will jump about 1,000 - is the torque converter being utilized at that speed??

And finally, stopped on a steep hill, in manually selected 1st gear the car will roll back. Not surprised. But! In 2nd, it won't roll back at all (!!) and since the engine doesn't sound like it's under load, I'm assuming it electrically applies the brakes? But not in 1st?? Why? And in auto gear select / D, it behaves the same as it would with 1st selected (rolls back).

I've uploaded the videos to a playlist on YouTube here.

So... what am I looking at?
 

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Torque convertor lock up and release. Normal. When locked it's like a direct connection similar to a manual. Improves efficiency and fuel economy, but at some point depending on the load and throttle position it will releae and the torque converter speed will increase. The only thing that had me baffled was teh RPM to Speedo until I realised it was in miles
 

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Discussion Starter #5
Torque convertor lock up and release. Normal. When locked it's like a direct connection similar to a manual. Improves efficiency and fuel economy, but at some point depending on the load and throttle position it will releae and the torque converter speed will increase. The only thing that had me baffled was teh RPM to Speedo until I realised it was in miles
I wish I could manually control THAT, would be quite handy. What's the point of being able to manually shift if it's going to pull that nonsense? Granted I could see doing this in extremes, but it wasn't that extreme, at least I don't think it was. You saw the video.
 

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35 MPG indicated isnt that bad. Take that car out of ECO mode. All ECO mode does is slow down a jackrabbit start in city driving, and try to hold the gears longer before a downshift. I have always gotten better mileage with it OFF. It may help slightly during city driving, but does noting but hamper at highway speeds and conditions. As posted above, looks normal operation, torque converter unlocking.
 

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Discussion Starter #7
Wait, wait, guys... I get it now. Selecting manual shifting tells the dumb computer "oh look, user wants to play even though ECO mode is on" and it unlocks the torque converter to give a bit of extra power before shifting is required. Putting it back into D tells it to go back to prioritizing ECO but then since it's in D on a hill it shifts down and blows all of that away. (I have managed to hold that hill normally though, perhaps at a different speed? I think it was 80 or 82, that makes sense then I guess.)

I just wish people would realize that there's another more practical use for manual shifting besides having fun (although that is also really cool of course).

Dang I miss my old Saturns.
 

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Discussion Starter #8
35 MPG indicated isnt that bad. Take that car out of ECO mode. All ECO mode does is slow down a jackrabbit start in city driving, and try to hold the gears longer before a downshift. I have always gotten better mileage with it OFF. It may help slightly during city driving, but does noting but hamper at highway speeds and conditions. As posted above, looks normal operation, torque converter unlocking.
Hmm, so would you recommend putting it back on for the in-town leg of the work route?

EDIT: Oh, and I heard that ECO also shuts off gas when not accelerating, but... I thought all fuel injected cars did that??

EDIT2: 35MPG is because I reset the average calculated for the Interstate trip. It's usually more like 25-28 for me and 30 to MAYBE 33 for my wife, depending on air temperature and a good tailwind.
 

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Hmm, so would you recommend putting it back on for the in-town leg of the work route?

EDIT: Oh, and I heard that ECO also shuts off gas when not accelerating, but... I thought all fuel injected cars did that??

EDIT2: 35MPG is because I reset the average calculated for the Interstate trip. It's usually more like 25-28 for me and 30 to MAYBE 33 for my wife, depending on air temperature and a good tailwind.
Leave the car in D around town. The only time I use the manual gate is to force upshifts for better mpg. But you can also lower shift points with a light touch on the go-pedal. For best mpg, I'd shift from a stop at 7/14/21/28 to get to 5th which is direct drive, and then move back to D. But with an easy right foot, the car will upshift when the tach gets to 2000-2100rpm, and that's the sweet spot for best economy. Eco mode does nothing other than lower shift points and cycle the A/C compressor on/off more often. Owners see mixed results with Eco, with some finding it hurts mpg without realizing (or admitting) that they're flooring the gas to keep the car from shifting too soon. If you use Eco mode and drive gently, it will help.

The car will shut down the injectors when you take your foot completely off the pedal and coast from speeds over 25mph. It will downshift as you coast to keep the rpm above about 1200rpm and will switch the injectors back on at just under 20mph. It is normal for those downshifts to be bumpier because it's keeping the converter fully locked and switching clutches quickly to avoid slippage since the car's momentum is needed to keep the engine crank spinning. It's a powerful tool available for keeping city mpg over the EPA estimate, but it takes some focus as you need to spend more time than you currently are without touching either pedal, while the car rolls down the road without burning a drop.

If you're looking for best fuel economy on the highway, you may want to go for a scan-gage or Ultragauge and set up a few handy parameters. These cars have variable valve timing on both cams and will change intake timing to delay the intake valve closing, causing them to mimic the Atkinson cycle. But the secret to getting there is low engine load (under 40%) and low throttle angle.(under 8%). You see the spark timing change, suddenly going over 40BTDC as cylinder pressure drops, and fuel economy gets close to 60mpg. Overall tank averages with mixed driving end up in the high 30s.

You mentioned having old Saturns. They used to blow past their EPA estimates easily, but they don't build cars that way anymore. The government outlawed them by requiring hundreds of pounds of [email protected] to keep people safe even as they drive without looking out the windshield. Higher weight means shorter gearing, which hurts mpg in all speed ranges. Also, Saturns - the original SW/SC/SL - also had countershaft automatics that were laid out like a manual gearbox but with small plate clutches in place of synchronizer cones. It would select each gear by applying its clutch. Honda used the same trick and that explains why old Civics also posted some great mpg. The 8 valve Saturn engine had better ratios and was tuned for low end power, and that was the secret to its better economy.

The Elantra has a long-stroke lightweight engine that doesn't start to produce real power until you're higher up on the tach, so most owners find their mpg doesn't match EPA because they're lead footing it and the tach is hitting 4 or 5 on each shift. I did two long distance road tests in an Elantra (vs Cruze Eco) to compare fuel economy. One revelation noted in both tests is the lack of low end torque in the Elantra caused the mpg to get murdered when climbing up the Cajon Pass on I-15. The car ended up having to downshift to 4th to maintain the posted speed. It would maintain speed in 5th, locked in via the manual gate, but you had to mat the pedal and the mpg was worse than it was in 4th at higher rpm. On flat ground, heading up past Victorville toward Ridgecrest, it was back up to 55-60mpg. The Cruze Eco also suffered on the climbs because the blender was running full tilt to maintain speed, but it didn't need the same rpm climb due to the added torque from forced induction.

If you're measuring mpg and trying to meet or beat EPA, get the Ultragauge and use it to "drive by the numbers". You can calibrate it to correct the odometer error built into the Elantra (about 3% under for most trim levels) when calculating mpg, and when you correct the car's trip odometer (number on the dash x 1.035 if you have a GLS and using the correct tire size), you find the mpg number on the dash is usually pretty close.
 

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Discussion Starter #10
Good info, thanks. Anyone know if a Cold Air Intake will help a couple MPG? I noticed the intake hose from the filter box looks really cramped with sharp angles. Was thinking maybe this instead might help: Injen SP1360P - Amazon I know a CAI probably isn't a miracle worker, but I do get the feeling the stock intake wasn't well designed just by looking at how the air would have to flow. Thoughts?
 

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Wait, hold up, the trip ODO is off? I have the Limited, and I think the right size tire, although the previous owner had 4 different brand tires on all 4 wheels (it needed an alignment bad when I got it, I forgot to mention, I did take care of that as well -- you could easily tell b/c the steering wheel was offset and it pulled pretty hard to the left).
 

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Cold air intake degrades mpg if it has any effect at all. Air flow and volume don't matter much at low rpm where there is little restriction other than the throttle plate. Cold air is more dense, and the computer adds more fuel where there is more air. Some hardcore mpg people actually fabricate a warm air intake to lower intake air density. In autumn, I block off the lower grille with foam pipe insulation so the only air intake is the slot above the bumper face. It helps the engine warm faster and also warms the air intake temperature. It helps to cut the efficiency loss that happens with the colder air, changing to winter tires, and low energy winter gas blends.

To improve mpg - especially on the highway - the one air upgrade that works is to add air to the tires. It helps with city mpg as well if you spend enough time not touching the pedals. I have tested the Elantra with pressures up to 65psi and found the gain flattens out above 50psi. At pressures above 50, the NVH gets worse far faster and the slight gain in mpg isn't worth the trade off.

The trip odometer is off. It will be anywhere from 2.5 to 3.5 percent under actual miles. If you go on a long drive on an interstate with mile markers, reset one of the trip odometers at a known milepost and drive. When you get to 20 miles, you will see your trip odometer at about 19.3 or 19.4. You can also use google maps to measure a specific route and then drive that route and calculate the offset/error there. Once known, it's consistent, so there's no need to check it all the time.
 

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Discussion Starter #13
Did some experimenting on the way to work this morning. Between 1,500 RPM and 1,750 RPM (35 - 40 MPH) there's a sweet spot that you can kind of feel. It's darned hard to maintain because of the delay in throttle response (that the ECO mode? probably should have tried with it off). Anyways I was getting 40 - 45 MPG for the short while I could maintain that cruise condition. Here's the kicker though. I checked a maps app and from the Interstate exit to where I work is 3.0 miles. There are 14 traffic lights and a traffic circle (I counted on the way back home). So you're going to be doing the econo cruising for about 20 seconds before you have to brake. Also idling the car while I got breakfast for 2 or 3 minutes dropped MPG to like 33 (here's where diesels are freaking AMAZING, they can idle all night on a quarter tank of gas... well, in the 90s anyways...).

Now for the Interstate, that's the other half (time-wise) and it's basically one hill after another, up and down, up and down, up and down. That's where I was hoping the Cold Air Intake would help, but if it only helps at high RPMs I don't think 2-3,000 would count, and you said it nerfs city MPG.

I think the lack of torque is killing me. I can't just putt around in high gear unless I don't have anyone cutting in front of me and I don't get any red lights, and on the Interstate, even if I manually gate in 6th gear the torque converter unlocks every 2-4 minutes to climb a hill.

I think a Hybrid drivetrain would help a lot. Then it could assist power up the hills, recover the energy on the other side, and easily handle the 3 miles in the city as electric-only or at the very least heavy electric assist for the stop and go.
 

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Did some experimenting on the way to work this morning. Between 1,500 RPM and 1,750 RPM (35 - 40 MPH) there's a sweet spot that you can kind of feel. It's darned hard to maintain because of the delay in throttle response (that the ECO mode? probably should have tried with it off). Anyways I was getting 40 - 45 MPG for the short while I could maintain that cruise condition.
You're on the right track. For finer control of the throttle, place your right foot between the console and the pedal so you're big toe is on the pedal. Then you can rock your foot slightly to adjust throttle just a bit. Best mpg comes when you're using just enough to keep the car at steady speed.

Here's the kicker though. I checked a maps app and from the Interstate exit to where I work is 3.0 miles. There are 14 traffic lights and a traffic circle (I counted on the way back home). So you're going to be doing the econo cruising for about 20 seconds before you have to brake. Also idling the car while I got breakfast for 2 or 3 minutes dropped MPG to like 33 (here's where diesels are freaking AMAZING, they can idle all night on a quarter tank of gas... well, in the 90s anyways...).
For lights on a route that you drive every day, start to analyze light timing and adjust speed so you catch a minimal number of red signals. Knowing how the lights are timed, you can avoid the dreaded "stale green" that will change by the time you reach the intersection. Steady speed and minimal brake use is the strategy for battling the "light to light" commute. When you know for sure you won't make the next green, coast. If coasting in D will cause the car to slow too quickly due to fuel cut, you can bump to N and the car slows more gradually and will hold onto 120-150mpg. As you approach the light, bump back to D and you will feel fuel cut begin and slow the car. If there's nobody behind you, just ride the fuel cut and slow down so the light goes green before you reach it.

Now for the Interstate, that's the other half (time-wise) and it's basically one hill after another, up and down, up and down, up and down. That's where I was hoping the Cold Air Intake would help, but if it only helps at high RPMs I don't think 2-3,000 would count, and you said it nerfs city MPG.
Depending on the speed limit, allow the car to slow when climing the hills and hold a steady pedal and let the car gain speed as it heads down the other side. The Elantra hates long hill climbs and the best you can do is to drive at a steady load to keep the car in top gear with the converter locked and let the speed fall if at all possible.

I think the lack of torque is killing me. I can't just putt around in high gear unless I don't have anyone cutting in front of me and I don't get any red lights, and on the Interstate, even if I manually gate in 6th gear the torque converter unlocks every 2-4 minutes to climb a hill.
It has reasonable torque, but the peak is closer to 5000rpm. Ever wonder why your Elantra has 148hp, while the late '80s Olds 307 (5.0 liter) they used in the big Buicks and Cadillacs also had 140hp? Does that mean the Elantra engine could power the early 80s 18 foot long 2 ton Buick Park Avenue? The secret is that horsepower is just "torque over time". If you cut peak torque in half but reach that peak at double the rpm, you get the same hp number. The last Olds 307 in 1990 was rated at 140 hp at 3200rpm and 255 lb⋅ft of torque at 2000rpm. The Elantra is rated at 148hp at 6500rpm and 131 lb-ft of torque at 4700rpm. Note that the peak torque is about half and peak rpm is about double. Horsepower ends up the same. But where the Olds was generating peak twist at 2000, the Elantra needs to head toward 5000 to get to its peak. Double engine speed and you double (roughly) fuel consumption, which is why you read all the moaning posts by people who are getting 20mpg out of their Hyundai. They've got a dent in the carpet under their gas pedal. It's fine if they want to drive that way, but they can't complain any more than I can complain about being fat when I eat Ring-Ding and Reese Pieces casseroles for lunch and wash it down with a large shake.

I think a Hybrid drivetrain would help a lot. Then it could assist power up the hills, recover the energy on the other side, and easily handle the 3 miles in the city as electric-only or at the very least heavy electric assist for the stop and go.
Hybrids solve the stop and go losses due to regenerative braking and electric assist. But some hybrids do run out of charge heading up steep hills and end up revving the little Atkinson engine like crazy to climb hills. The Prius C and Honda Insight are famous for redlining their little chainsaw motors on long climbs when battery power runs low. The Sonata hybrid does well on hills because it retains its 6 speed automatic so it can downshift and multiply electric motor effort on hills. The downside is higher cost of the car and hidden maintenance costs (MG2 belt needs replacement at or before 100k).

It sounds like you have a fairly short commute. Better fuel economy is well within your ability if stick to the basics of economical driving.

Here is an old photo I snapped in my Elantra - driving on the highway in a 55 speed zone, with the engine running in its super-secret lazy-intake mode (note load around 40, timing far advanced, and over 60mpg), to show what's possible.

447327
 

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Mine shifted strange for awhile. I was told I needed a transmission. Find out it's a transmission sensor. These cars are known for bad shifting. After I changed the sensor it was so much better and saved thousands
 

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Mine shifted strange for awhile. I was told I needed a transmission. Find out it's a transmission sensor. These cars are known for bad shifting. After I changed the sensor it was so much better and saved thousands
How much did that run you (about)?
 

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My 2012 had shifting issues from about 60k to 99k miles. It was intermittent and would only happen once every few weeks. I read here about the tranny temp sensor issue so prior to the end of my 100k warranty, I took her in at about 99k miles and they changed out the temp sensor and all has been perfect all the way until now at 154k miles.
 

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HJElantra, what transmission sensor? What does it sense (RPM, temp, gear???) Under the battery? That sounds like the neutral position switch. Is it external to the tranny?
 

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It's technically calles a transmission fluid sensor. Any other explanation is out of my realm. Sorry. I just know how much of a relief it was and the difference was amazing.
 
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