2004 Prius, why was I stuck at 41mpg, but can get 55+mpg with the same car just because I believe I

Would love to read any and all comments that might come from this discussion. Thanks.

I have driven my Prius now over 210,000 miles since buying in November 2005. I initially hoped to obtain the elusive 60mpg advertised with my 2004 and many other years, but gave up, figuring my lead foot is not conducive to good gas mileage. I often would search ways to improve mpg driving, but either didn't understand or have the knowledge that I could strive for this accomplishment.

Just last month I picked up a few pointers, thank you priuschat community, just after receiving my ScanGauge2, and began accepting the task of improving mpg.

My 210,000 mile average was 41.2mpg. my first goal was 50mpg, and took me a month to attain (started at 233,000 on the odometer, now - 237,000). Within 175 miles of reaching that goal, I reached my 55mpg goal, and am continuing same tank with a goal of 60mpg to be reached somewhere in the weeks or months to come.

I know many have hyper-miled amazing results with the Prius, it just doesn't make sense that the answer may have been mindset, and not vehicle capability. I have so much to share, and am so excited with this new found (for me) Hypermiling mpg. I probably hold the record for the most towed weight for a Prius (7000Lbs gross), and loved I was fastest off the stop light about 90% of that 210,000 miles. Though now hate the idea of giving up this phenomenal mpg with heavy loads or racing at the stop light, lol. I so enjoy the prospect of a reason to drive to another destination. My daily commute of 100 miles is not enough anymore, I am "chomping at the bit" to see what new reading I will get next time out.

I must say, I worried a bit to buy plain jane Ignition Coils from China (4 for $65), but can only see a marked improvement already over the OEM (I am guessing, 237,000 old) originals. Although after that long, the car still ran good, and my goal of 50mpg was attained, just this last 175 miles have been with the new set of ignition coils. The original set only had 2 possible symtoms: 1. the engine ran just slightly rough. 2. At highway speeds, a sudden lull in power would occur, causing me to push the throttle 1/4" further to maintain the same speed, then 10 minutes later the power might return. The spark plugs were changed at 137,000 and regapped at 233,000.

 

It is amazing what I've learned since taking up the cause to reduce fuel consumption. Pulse & Glide, monitoring car vitals- watched SOC (HV battery %) and cWT (Coolant Temp in celcius), once the coolant gets to 88cWT, then I should switch to something else to monitor. Also been watching Bta and HPR, and will try the timing.

In the spirit of getting off the gas pedal quickly, I get close to desired speed (on the low side -95%), then back off the pedal and glance at the instant mpg, My minimum cruise setting is what the car has recently been able to maintain speed on a flat stretch of road, at this point in my learning curve, is 60mpg. If I see 1 or 2 foot/second rise hill coming up, I anticipate, by adjusting the pedal to 50mpg, and ride out the hill, loosing ~5 mph on 1 ft/second hills & ~10mph on 2ft/sec (as perceived on the GPS 1 second altitude updates). My cruise speed was 7% over speed limit before hypermiling, and now am happy with 62mph max on the level, to 3% under speed speed limit, whichever is less.

I believe the Prius adjusts mixtures based on drivers power requirements. Need more power, you get a richer mixture. It has to take hundreds of miles to undo these settings as I witness in my ever improving results as time goes on.

 

Reserved - Forum all, or bust.

 

I am guilty of overuse by a long shot. My commute alone quadruples that, I will comply where I can. The short trips to get a few groceries near my house was killing the good mpg, so I used less in that area. Some short trips were inevitable, so I'm finding the short trips are improving my mpg now.

 

Thank you for that, have read through about half last night and will continue today. Very interesting perspective on the testing.

 

55.8 mpg averaged 265 miles with last night's fillup. Couldn't pass up a local gas station that hadn't jacked their price up by 12 cents like all the others $3.38>$3.50, bet they changed it this morning. So far that is 14.6mpg better than my average. A 35% improvement over my 210,000 average of 41.8.

The less I demand of power from the Prius, the leaner it sets the mixture? Can't quite wrap my head around why this great mpg. On the flat areas at 55mph, I was easily getting 60-65mpg on the instant mpg MFD. This is so not me, but I know how to get better mpg now, and have the hypermiling bug, I just love this, for me, new found enjoyment. Then for the 2 mile drive to home, the engine hardly came on so the 2 mile average was 99.9mpg, Oh joy.

 

Started on the wrong foot with this new tank, somehow managed to average 34.8mpg for the 6 miles driven during my days off. Gave it my best shot for today's 43 mile commute, and wow, still amazed at the change in me. Started the day 34.8mg (@6mi), broke 50mpg (@24mi), broke 53mpg (@36mi), and finished with a reading of 54.7mpg (@49mi).

I now manually cruise control with mpg readings on the MFD, and its getting easier as I learn to listen for indications that my present mpg setting on the foot pedal either too much/too little, and getting better at maintaining speed with mpg priority.

The cruise control is really bad and I don't use it anymore. Just an overpass on the freeway is about 2% grade, when you prioritize the mph, mpg really suffers for the period over these overpasses.

Scenario 1: Cruise control set, driving flat freeway w/50mpg, 2% grade overpass encountered, maintaining mph, w/25mpg to the top, 75 mpg down the other side, and resume 50mpg. (average ~42mpg)

Scenario 2: Manual foot pedal set to 70mpg, driving same flat freeway
...(Something weird, each tank as I improve mpg, the same stretch gives improved mpg, following are examples of Goal and resulting mpg: 50mpg was 55mpg flat; 55mpg was 60mpg flat; 60 was 70mpg flat; continuing with Scenario)...
w/70mpg, 2% grade overpass encountered, adjust pedal to 60mpg, ride out 2% grade, w/60mpg to the top, 6mph lost on grade, 100mpg down the other side, 6mph regained, and resume 70mpg. (average ~66mpg)

Problem is, it is impossible to compare. What I need is mpg programmable cruise control to imitate Scenario 2, I can't get 70mpg on the flat when using cruise control, and approximately 50 miles beyond the computer takes time to regain that excellent 70mpg on the flat. My main point was to maintain my mpg at my goal for 2% overpasses, and above that for 1% grades. Always maximizing mpg while compromising only to my goal for 2% grades.

In Summary, just how many of these mpg improvements I will encounter? I've always believed a car can get what it is rated for, for the Prius that average is about 45mpg according to fuelly dot com. Hypermilers might already know there are great mpg gains in all vehicles, but I am a newbie to this, and can see the wonderful results, though I can't comprehend why the bonds have been broken for a 210,000 mile 41.2 average Prius with ole lead foot behind the wheel.
....Cheers, I am Mike

 

My normal lead foot driving required Cruise Control, otherwise my inattentiveness would usually drive up the speed, then have to back off. Cruise control helped maintain speed and save fuel for those reasons. What is bad about cruise control, it will keep your speed at all costs, usually with short periods of low mpg as a result. Not saying Cruise is bad, just can't be of any use on my present course of mpg addiction. Cheers.

 

I've been there too. Fastest off the stop light, works most of the time, but occasionally fate pairs you with a Shelby, and a few others that are just pure power. Funny, I once paired to a ford pickup, I had four passengers just finished eating at Hooter's. Could tell he peddle down roaring along side us, and my passengers were enjoying the show. I was playing him a bit, just giving enough to keep up with him, and hearing the chatter in the car was fun, then I announced I was done and floored the Prius, and left him behind. My passengers were quite impressed with that much reserve power.

My other love was to use my eco car as my Pickup, calling the 2004 Prius "My 35mpg Pickup", and enjoyed putting the car to many tests, but have already mentioned that elsewhere. No way I can do that in my present hypermiling mode, lol.

Tonight I've searched, and found an old ecomodder thread that discusses mpg priority Cruise Control, and finding it very interesting read, even though 5 years old (written 2008).
Cruise Control (with MPG sensitive logic) - Page 5 - Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com

 

I must have a heavy foot. When I drive like there is no tomorrow for 210,000 miles it was slowly diminishing mpg started with about 43 mpg and ending with about 41 except for unexplained tank of say 49 once in a great moon. I see my biggest easy fix was to get to speed, then spend more time maintaining speed, where before I tended to press just a little more on the gas peddle so for a majority of the trip was a slight acceleration, and by just swapping that alone to getting to speed and maintaining speed, and sometimes allowing the car to slow a bit over a small hill, I achieved much better results. I am unlearning a lot of bad habits that kill mpg, but still don't let it slow the cars near me, and when I need to get there quick, I still have the normal driving habit. Cheers.

 

Ha, exactly. Fastest off the green light, unless I happened onto a Shelby or other fast car, they always showed me true acceleration.