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New Traction Battery did not cure my low MPG

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Paul.Ivancie, Jan 22, 2015.

  1. Paul.Ivancie

    Paul.Ivancie Member

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    2017 Prius Prime
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    Prime Advanced
    Statistics:
    2006 - 230K miles - 52MPG pre-Ethanol, 47MPG post-Ethanol
    Over 50% highway driving.
    Prior to battery failure, MPG was falling relentlessly (low 40's), attributed to Old Age (The car's!).
    Then: Red Triangle of Death. Code PA080.
    Installed rebuilt battery at 222,400 miles (18-month parts and labor guarantee.)
    MPG recovered, as expected (more accurately: as hoped).
    MPG started falling again. No obvious problems in Battery, but Block 6 consistently had lowest voltage.
    (But only by less than a tenth of a volt.)
    MPG starting degrading again, this time to unprecedented levels (mid thirties!)
    At 229,700 miles, weakest battery module failed. Replaced bad module (Module 11 in Block 6.)
    After removal, bad Module's resting voltage is 6.67 Volts.
    Techstream shows a pretty good balance between all 14 Blocks. (16.48V to 16.72V at 54.5% SOC)
    No block stands out as consistently low. EV performance back to normal.
    Filled tank. After 100 miles, OSD shows MPG = 34.5.
    Am I being alarmist? Should I wait to accumulate more data before going ballistic?
    adTHANKSvance,
     
  2. CooCooCaChoo

    CooCooCaChoo Active Member

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    12V aux battery in the trunk?
    Other maintenance?
    Traction battery was a remanufactured part?
     
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  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Since you installed a "remanufactured" battery which had a failure after only 7K miles, that battery apparently wasn't in great condition to begin with, so 1) the other modules may not have adequate capacity and 2) another failure may occur in the near future.

    What are the low ambient air temperatures in your area currently?
    How many miles do you typically drive on one trip and at what speed?
    Are any warning lights currently on?
    When were the iridium spark plugs last replaced?
    What is the condition of the engine air filter (is it clean) and the exhaust system (any restrictions which prevent the free flow of exhaust gases)?
     
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  4. Paul.Ivancie

    Paul.Ivancie Member

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    Well...
    I did have to replace the "motorscooter battery" in the trunk at about 100K miles. It failed after a cold soak at -10 degrees Fahrenheit while I was visiting in NY. Normally, my car is garaged 100% here in MD, and rarely sees weather extremes like that.
    This winter season, our outdoor temps have rarely dipped lower than freezing, and the garage is at least 10 degrees warmer than outside.
    I also just changed my muffler. A hole had developed in the front muffler pipe about halfway between the muffler and the flange where a small heat shield was tack welded to the pipe. I installed a stainless steel muffler (which still has ordinary steel aluminized input and output pipes.)
    Over half of my 35,000 miles last year were spent in round trip driving up North to see my children in NY and MA (350 and 520 miles.)
    My normal daily drive here in MD rarely tops 14 miles (I am retired.) I habitually drive precisely 1 MPH above the speed limit, and have not changed that habit in 40 years. I am usually the slowest car on the road. I have had to make exceptions to that rule when I drive on the inner and outer loops around DC and Baltimore, or be subject to rear-end collisions; so, I stretch my limit to 61 in the 55 zones.
    The only code I have seen is the PA080.
    I have asked the dealership if I should do any minor tuneup procedures in the engine compartment (like plug wires, plugs, hoses, etc.) and I have been assured that if they thought it were needed, they would not hesitate to suggest it. At my wife's insistence, I have maintained a rigorous 5K preventative maintenance schedule exclusively at the Toyota dealer, so they know me pretty well.
    The air filter looks almost pristine, but the pre-filter that is sealed into the air cleaner lid looks quite dirty. I don't remember replacing the lid.
    When I bought the car, one could hardly hear the ICE when it kicked in, but now, it sounds like the noisiest valve train I have ever heard. I add a quart of oil in between 5K oil changes, and have asked over and over if I should consider doing a top end overhaul. The service manager assures me that the engine is totally normal. I have scheduled a service for tomorrow, and I will ask again. *** Sigh ***
     
  5. Paul.Ivancie

    Paul.Ivancie Member

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    I am prepared to play "whack-a-mole" with battery modules. The "PriusHybridRepair" guy is very serious about honoring his 18-month guarantee, but after that expires, I am planning on "rolling my own", since I am a retired E.E. I tentatively plan on buying a four-channel battery charger (or two, or three,) and a grid charger. I am making plans for a wiring-harness appliance that will establish connections for easily charging the 28 modules, four (or eight or twelve) at a time, and connecting them in parallel, all in keeping with what I have been reading about pack balancing. More research and cost analysis will be done first.
     
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. Regarding the 34.5 mpg reading per the MFD, did you reset that gauge? If you did not reset it after refueling, then the gauge will display a cumulative mpg reading from the last time it had been reset.
    2. Regarding your 12V battery, it sounds like it is pretty old. Measure the voltage in the morning before you start the car to see what it is. If lower than 12.6V, put it on a charger or consider replacing it soon. 14 miles / day is not much usage and the battery may be partially discharged.
    3. What is your tire air pressure? I suggest 44/42 psi.
    4. The "filter" in the air cleaner lid is charcoal and the purpose of that is to absorb HC vapor which rises out of the intake manifold into the throttle body assembly. There should be no need to replace the lid.
    5. When were the iridium spark plugs last replaced? If you don't have a service receipt showing this was done within the last 100K miles I suggest you have that done now.
    6. Your car logged 230K miles, the engine is no longer new. Oil consumption of 1 quart in 5K miles is quite good considering the odometer reading. Some amount of valve train noise is to be expected. You could spend ~$600 to have the valves adjusted, the camshafts have to be removed because "bucket" spacers are used. That may not be the best use of your repair funds.
     
  7. Paul.Ivancie

    Paul.Ivancie Member

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    1. I always reset my MPG and always fill my tank. I note the Odo reading and indicated MPG on the receipt. Then, I enter the date, Odo reading, Co$t/gal, and price paid into a spreadsheet.
    The spreadsheet calculates the per-tank MPG, the last 10-tank MPG, the lifetime MPG, the cumulative gasoline cost per mile, and a few other things that interest me.
    2. The battery was evaluated during my just-completed (within the hour) service. It passed their load test easily.
    3. The dealership keeps inflating to the "book" value: 35F and 33R. When I get it home, I inflate to 40F and 38R.
    4. That lid is rather pricey, all right. They just quoted me $191 to replace it. I think I will live with it as is.
    5. The dealer has scheduled a plug replacement at 240,000. The line item is checked OK on the multipoint inspection sheet.
    6. (The kicker) The dealer measured only 1.9 quarts of oil in the drain-out. That is 2 quarts down. Their opinion of the "state-of the-engine" has changed from "It's normal wear and tear," (last 5K service) to: "You need a major overhaul!" Cost: $5415 (including "free" rental car.) My garage floor is painted with the fancy epoxy floor paint. I have never seen a spot of oil on it, so all of the missing oil is going out the tailpipe.
    7. I am now researching new engines, rebuilt engines, and partial (top-end) overhaul.
     
  8. stonerider

    stonerider Member

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    You could go and buy a whole Prius for $5415.
     
  9. JC91006

    JC91006 Senior Member

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    I would just add oil when needed and make sure it doesn't run low. With mileage and battery issues on this car, you would be crazy to dump $5000 in it.
     
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Exactly. What is so hard about adding a $4 quart of oil every 2K miles or whatever is needed? That certainly beats spending $5K.

    If you are determined to replace the engine, then install a used engine from a salvage yard which you can probably buy for $500 or less.
     
  11. Paul.Ivancie

    Paul.Ivancie Member

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    Right! $5K is out of the question.
    A few years ago, when I burned up my engine on my '69 Pontiac Catalina at 100K miles, I bought a wrecked (accordioned) '67 Grand Prix, pulled the engine and tranny, parted out the remainder, put the engine in my car, completely rebuilt the '69 engine, and then sold the '67 engine. The only cost was the money for the rebuild parts, giving the tranny to the guy who taught me how to do the overhaul, and then giving my share of the universal engine stand which I built (from scratch with the same guy) to him when I was done. The rebuild lasted for another 100K miles. Could I do that in this case? The junk engine was simply a placeholder so I could still drive the car as I rebuilt the engine. Then I peddled it. Just thinkin'...
     
  12. Patrick Wong

    Patrick Wong DIY Enthusiast

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    You really do not want to rebuild the engine. That would require sending the block and head to a machine shop to have new valves, pistons, bearings etc. installed, the valve seats reground, the piston bores cleaned up. My guess is that you could easily spend $2K or more on the rebuild - call your local machine shop and see what they say.

    Just buy a low-mileage used engine and you will be good to go.
     
    #12 Patrick Wong, Jan 23, 2015
    Last edited: Jan 24, 2015
  13. uart

    uart Senior Member

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    At 230k miles you need to be a bit more vigilant about checking the oil. I mean you shouldn't be reliant on the dealer to tell you that you are running low. I wonder how many other times has it been low without you knowing?

    Anyway, I'm sure a badly worn engine is going to give some loss of MPG. I'd be pretty sure that is at least part of the issue.
     
  14. Paul.Ivancie

    Paul.Ivancie Member

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    I have been routinely adding a quart at the 2500 mile mark, but this Christmas season left my head spinning. I would wake up and have to remember which state I was in: New York, Massachusetts, or Maryland. So I let this one slip by.
    At each oil change, I would bring my empty quart container to have it filled with the same oil that they were putting in (the dealer is very accommodating; I don't get charged for it.) This time, my container was not empty!
    From now on, I will be bringing two empty quart containers. I wonder if they will be as nice. I can just see them salivating over the profit on the engine rebuild. Free oil? I think not.
     
    #14 Paul.Ivancie, Jan 24, 2015
    Last edited: Jan 24, 2015
  15. sorka

    sorka Active Member

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    My oil consumption was up to about 1 qt every 1500 miles. Changing the PCV valve, which took me about 30 minutes(kind of a pain on the Prius) and 1000 miles later not a single drop consumed. So you might try doing that first. For good measure, I run a few tanks with the 12 oz bottle of Techron. On the off chance you have sticking oil, rings, I'd also add a 1/2 qt of MMO or use the high mileage oil which has also been known to free up stuck rings. I did the PCV, Techron, MMO, and changed the plugs all at the same time. It was likely the PCV valve that did it, but I could have also had stuck oil rings.

    As far as fuel economy goes, the only thing I've seen mess it up that badly is bad wheel alignment.

    Since neither alighnment or PCV valves were mentioned in this thread which are the most likely culprits for these issues, I'd get that stuff done first before worrying that you have a major problem.

    If you're rear alignment is out of spec at all, you'll need aftermarket shims. I did that and it made a huge improvement in the fuel economy. I get 55 MPG if I keep it at 65 MPH or less. My wife drives 80 MPH and only get's mid 40's.

    Our 2009 Prius is up to 186K miles. A fiber optic borescope in the spark plugs holes with the right angle mirror attachment to look at the cylinder walls showed no scoring and all the original honing cross hatches are still present, so these engines don't wear down very quickly.
     
    #15 sorka, Jan 25, 2015
    Last edited: Jan 25, 2015
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  16. JC91006

    JC91006 Senior Member

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    This is truly amazing that you went from burning 1 qt 1500 miles to zero with an engine that has 186k miles.
     
  17. sorka

    sorka Active Member

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    Not if the cause was a bad PCV valve. If it was worn rings or valve guides, then it would have had no effect.
     
  18. Paul.Ivancie

    Paul.Ivancie Member

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    These are all good ideas.
    Since 222K miles:
    1. Replaced a front wheel bearing/hub assembly which had prematurely failed after a year. Upgraded to Timken from Autozone house brand.
    2. Since I had the front end apart and had already obtained the parts in advance (waiting for the noisemakers to start squealing), I replaced the front rotors and pads, and did a four-wheel alignment. In preparation for doing the alignment, I attempted to clean up the tie rod ends to make it easier for the technician to do any adjustment. I could not get them to budge. Well, neither could the mechanic, so I let him replace both tie rod ends.
    3. Replaced the muffler (already mentioned above).
    4. Replaced the tires with Michelin Defenders.
    5. Swapped out my HV battery (twice... the reason I started this thread).
    6. Had two normally scheduled service intervals, complaining each time about low mileage and excessive engine noise.

    Since it cannot possibly hurt, I am definitely going to try the PCV valve, Techron, and MMO right away. I have been complaining since its inception about the 10% Ethanol mandate, and I recently was informed about a station that sells pure gasoline -- and not too far away. I am going to start using that stuff ASAP. The problem will be: if I notice a significant effect on my MPG, what will have caused it? Maybe I should initiate the measures in stages... PCV first, followed by the additives, followed by the gasoline upgrade. I am now sitting with an almost full tank. I should be able to cruise for a couple hundred miles at each of the first two stages. Then, my tank should be close to empty, so I can fill it up with the pure gasoline.
     
  19. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Very interesting.

    At what odometer reading did you replace the PCV valve?
    When you removed the old PCV valve, did you shake it to see if the valve mechanism rattled or not (if not, then the valve was definitely stuck.)
     
  20. sorka

    sorka Active Member

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    I replaced it at about 184K miles. The old valve was not stuck, but there was a lot of varnish in it. Just because it rattles when you shake it doesn't mean it's a good seal.
     
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