Winter Starts All the Way Through Summer- Mitsubishi Service said Nothing was Wrong?

So I bought my mirage last year in august and when I initially got her, she worked just as she was supposed to. I drove it straight across the country and had no problems. The fuel usage was even better than expected.

In the fall of last year, I started getting what a lot of mirage owners are used to in the winter, greater fuel usage upon start up. I thought it was just due to the cold weather setting in and let it continue on. However this behaviour, that didn't exist last summer, never stopped even through this summer. And I have no explanation for this.

All the maintenance I can think of is up to date. Engine oil, transmission oil, air filters, break roters and shoes have all been updated. I took it to Mitsubishi thinking that it had to be an issue with the cold start sensor, and they said that their diagnostic system said the vehicle was preforming just as it should. This makes no sense however as it literally didn't do this last year, and I'm quite certain the vast majority of users here don't have this problem.

The tires are different and do have an impact on milage, but that difference is 0.4-0.5 L/100 km on the highway. I know this, because when I reset the read on a highway drive, I can see what my milage on the highway is, and while it used to be 4.4-4.6, it is now in the 4.8-5.2 range. This I can accept. Whats really killing my efficiency is these winter starts that Mitsubishi themselves aren't acknowledging, and I'm not quite sure what to do about it. They exist, however. The car was indeed preforming differently last year.

Does anybody have any suggestions? Is there anybody else I can go to?

Let me know!

If you think cold weather is the cause, address this by using a engine block heater - if only to see what happens.

Have you made entries in the forum fuel economy log? That would be an easy way to keep track of fuel consumption, and we could see it too.

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Originally Posted by Eggman

If you think cold weather is the cause, address this by using a engine block heater - if only to see what happens.

Have you made entries in the forum fuel economy log? That would be an easy way to keep track of fuel consumption, and we could see it too.

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I don't think cold weather is the cause as it happened all the way through the summer. I am having starts as if the car thinks it is cold even when it's not.

The average is more than 1 L/100 km different than last year, and I can only attribute half of that to tires. And on short drives its really poor, as it would be in the winter, but it did this all summer. If I didn't do so much highway driving, the average would honestly be much worse.

Even without strict tracking, I can tell it's notably worse, much like that other guy who was having a similar problem.

I'm just at a loss for what to do to fix it; I've literally tried everything, even taking it to Mitsubishi so they could tell me what the problem was to no avail. And there most certainly is a problem considering the vehicle didn't behave this way when I bought it.

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Originally Posted by Spadesheart

The tires are different and do have an impact on mileage...

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Remember that nothing has less rolling resistance than a worn out Low Rolling Resistance tire. So even if you replaced your tires with a new set of OEM Enasaves, you would still notice a slight reduction in your fuel mileage.

You didn't mention what tires you are using. If you bought some off-brand tires that aren't Low Rolling Resistance, that could make a significant difference.

I know this sounds crazy...but you aren't driving around with your automatic climate control on all the time, right?

If there is something wrong with your car (like a bad coolant or air temperature sensor), this could have a significant impact on fuel mileage. There is a reading in the car's computer called "Fuel Trim." It's basically a reading that indicates if the computer is being directed to use more (or less) fuel than usual. You can read more about it here:

Fuel Trim as a Diagnostic Tool

A good tech would have looked at your fuel trim. A tech who's only getting paid 30 minutes of warranty time to look at your car may have just looked for error codes.

Good post, TOP FUEL.

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If you want to see what temperature your car thinks it is, you can also view that live if you get a scanner plugged into your OBD2 port. more importantly, the air intake temperature sensor and coolant temp

Depending on your mileage you may want to clean your mass air flow sensor (if equipt, some markets do not have them)

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Originally Posted by Top_Fuel

Remember that nothing has less rolling resistance than a worn out Low Rolling Resistance tire. So even if you replaced your tires with a new set of OEM Enasaves, you would still notice a slight reduction in your fuel mileage.

You didn't mention what tires you are using. If you bought some off-brand tires that aren't Low Rolling Resistance, that could make a significant difference.

I know this sounds crazy...but you aren't driving around with your automatic climate control on all the time, right?

If there is something wrong with your car (like a bad coolant or air temperature sensor), this could have a significant impact on fuel mileage. There is a reading in the car's computer called "Fuel Trim." It's basically a reading that indicates if the computer is being directed to use more (or less) fuel than usual. You can read more about it here:

Fuel Trim as a Diagnostic Tool

A good tech would have looked at your fuel trim. A tech who's only getting paid 30 minutes of warranty time to look at your car may have just looked for error codes.

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I completely agree with the tires and they do have an impact, but the impact seen is logically different. There is no reason for tires to make the car consume more fuel at the start, cause the A milage read to spike specifically for the first few minutes of driving, or greatly reduce efficiency on short drives over longer ones. The car didn't do this before. I am almost certain that it is enriching the fuel as if it were doing a winter start.

They're 175 michelin winter tires on steelies right now, nearing the end of their life.

The climate control does make a big difference, but i am quick to turn off the AC unless it's very hot, and even then, the effect is not consistent with last year.

I just read the article on fuel trim.

Should I just take it back to Mitsubishi and tell them to look at that?

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Originally Posted by MightyMirageMpg

Good post, TOP FUEL.

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If you want to see what temperature your car thinks it is, you can also view that live if you get a scanner plugged into your OBD2 port. more importantly, the air intake temperature sensor and coolant temp

Depending on your mileage you may want to clean your mass air flow sensor (if equipt, some markets do not have them)

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How would I go about cleaning it? Where is it even?

Are you basing your fuel mileage solely on what the dash says? I know they're relatively accurate but I wouldn't put all my faith in one. Especially the trip A.

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Originally Posted by Spadesheart

How would I go about cleaning it? Where is it even?

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That's a good question. I've never done it before so let someone else chime in. But it's located on your airbox.

Its located in the circled spot. The picture show a car WITHOUT the sensor.