mileage drop

dealer added too much oil........go back to him...have him put oil between the dimples on your dipstick.

 

1. The weather got a lot colder.
2. The tech let some air out of your tires.

Oddly enough the remedy for both is to check your tires. Use 42/40 PSI front/rear for noticeably better MPGs. Then wait for warmer weather.

A *dealer* told you it didn't need an oil change? He gets a gold star for honesty (assuming that he was correct). So why did you have it changed a week later?

 

may want to take a look inside the filter box too, make sure everything is copastetic. only takes a sec.

 

The air filters are "stupid easy" to change. Next time buy your own & spend 2 minutes changing them.

 

You may also want to clean your Mass Air Flow (MAF) sensor. It is attached to your throttle body and is easy to take off clean and put back. You need to buy a can of MAF sensor cleaner. There is a good description on here that tell you how to do it. Just do a simple search to find it if you decide to try it. I had my mileage and my CEL come on because of a dirty MAF sensor. My local dealer wated to replace my fuel injectors at a cost of $1150. You can get some oil in your Throttle body if the oil was over filled. Maybe the MAF got dirty from this as it is attached to the throttle body. It's as easy cheap fix to try. My mileage did go back up after I cleaned mine.

 

Huge mileage drop on 2005 Prius Gen II

Does anybody have any suggestions?

My 2005 Prius is now over 125k miles. Back in the winter, the 12v battery died 3 times following the addition of daytime running lights to satisfy Canadian importation regulations (the local dealer added a relay that would turn the headlights when car is powered on.)
I had the battery replaced soon thereafter.
At the time I noticed the mileage had dropped but attributed it to the colder weather.

In the spring the city/highway combined mileage was between 45 and 50 mpg whereas it used to be in the 55-60 mpg range as late as last summer. I recently did a complete tank of just city driving, and the mileage is 35mpg vs 60mpg last summer.

Other items to note:
1. at slow accel the engine kicks in at 15 mph vs previously being able to get to 35mph.
2. After long periods between uses, the hybrid battery level guage has dropped two notches from when the car was turned off.
3. Hybrid battery shows 7/8 charge and the gas engine turns on immediately at power up.

It looks like the highway mileage is affected less, it is now 45-50mpg vs previously 50-55mpg.
I asked the dealer to investigate at the last service at 125k miles. They claimed to have run a diagnostic on the hybrid battery and say it is within specs.
The dealer also claims that it cannot investigate further without guidance provided by an error code or check engine dash light.

What else could it be?

 

Re: Huge mileage drop on 2005 Prius Gen II

^^^
Please answer http://priuschat.com/forums/gen-ii-...-answer-these-questions-esp-if-youre-new.html.

Unless you're fairly good at pulse driving, hypermiling and had an ideal long commute w/few stops, your claims of 55-60 mpg on a Gen 2 sound a bit high to me. My lifetime average on my 06 is ~45 or 46 mpg. I've never had a complete tank as high was 55 mpg.

 

He may be reporting Imperial Gallons, 1.2 times the size of US Gallons.

 

First question: yes, getting 55mpg was never an issue as starts and stops are timed and traffic light patterns are well known.

Have you read This Thead Yet?

- What fuel economy are you getting and how are you determining fuel economy? (trip computer or manual calculations) the fuel efficiency I noted is the average of multiple trips. Calculated by computer and manually.

- What fuel economy are you expecting and why? I am expencting the same fuel efficiency i used to get last year. 55 combined with a 50/50 mix of city and highway.

- What are the approximate outside air temps? between 60 and 90 F

- How long are your trips? Variable but unchanged from last year.

- How much of it is city vs. highway? Roughly what's the average speed in overall and and of each segment? Is there a lot of stop and go driving? Variable but no change from last year.

- What region/state are you in? (if you haven't set your location in your profile) Quebec

- What's the terrain like of your drives? (e.g. flat, gentle hills, steep hills, etc.) No change - Flat

- Is your oil overfilled? (i.e. above the full mark on the dipstick) No
How old is your 12v battery? What is the voltage reading of your 12v battery after sitting over night? (Method Here) 12.5V, dropped to 11.9 when in 2nd ACC mode (loaded)

- Have you had your alignment checked? Any pulling or abnormal tire wear? Yes, no pulling or abnormal wear.

- Are you using the factory tires and wheels? If not, please indicate tire make, model and size (e.g. Goodyear Assurance Fuel Max 185/65R15). Factory wheels, tyres are Mastercraft 185/65R15.

- What are your tire pressures? 40 PSI

- Make, model, year, engine and transmission of previous car? (e.g. 08 Honda Civic Si 2.0L 4 cylinder, manual transmission) What did you actually get on the same trips/commute? (Please give us actual numbers, not EPA ratings.)
NA

- How are you trying to drive (e.g. trying to stay in electric only?) and how hard are you braking? Try to stay in Elec mode in city stop-start conditions and regen braking as much as possible.

- Are you "warming up" the ICE (internal combustion engine) by letting it idle after powering on? Never did.

- Are you driving using D or B mode? D mode, duh!

- HVAC settings? Are you using the heater, AC, auto mode, etc.? If using auto, what temp is it set to? Don't use AC unless absolutely needed, mostly just fresh air. If really hot, then AC set 72-75.

- If reporting a mileage drop, did anything significant change on your car (e.g. accident, hit a curb or big pothole throwing off alignment, oil change/other maintenance/repairs, changed tires or wheels, etc.) or your commute? No change just the car got older. There have been 4 scheduled services including the major 120k in the intervening time until now. It is hard to say when the mileage drop actually happened. I waited until summer for a direct comparison to discount cold weather effects.

 

Are you from the 60s? I'd appreciate serious and constructive feedback!

:focus:

 

Yes I am, 1955 actually. I fondly remember Esso Imperial in Vancouver BC in the 60s.

All I offer is serious and constructive feedback. Misguided perhaps, but always the best I have. This is a world wide site, you will find many here still using Imperial Gallons.

 

probably needs a new 12v.

 

I disagree. Apart from some former colony, developing countries most of the world uses litres.

 

I changed the 12v battery at Prime Toyota of Boston (former Clair Toyota) on VFW Parkway in May 2011.

Keep the suggestions coming!!

 

Correct in theory, but in practice we don't get many 'developing country' posts compared to posts from Britain that still use Imperial Gallons, and posts from Europe that convert to Imperial Gallons when they bother to convert to any gallons.

You will see this a LOT in diesel fanboy quotes " [Some tiny diesel not imported to US] gets 70 MPG, the Prius only gets 50 MPG! Naa Naa Naa!" And then we point out that they used Imperial gallons and 50 * 1.2 is 70, so their tiny example is doing no better than the Prius. Happens here about every month.