Lost 10mpg after EGR clean, etc. Now losing mind!

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by FriedCells, Oct 12, 2020.

  1. FriedCells

    FriedCells Junior Member

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    While it wasn't required in the Prolong instructions, I did measure each battery anyways. I'm not sure if there's a better way to measure IR, but basically, as far as I know, doing the load test on each battery starting from a similar voltage level, put the load on it for 1-2 minutes depending on the draw, test voltage after that time, remove load, check voltage again about 30 seconds after removing load. If any battery shows a statistically significant higher draw, or doesn't 'bounce back' after load removal as well as the others, then those are losing their IR capabilities. Luckily, all mine were fairly close in the results, not even showing one module questionable.
     
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  2. FriedCells

    FriedCells Junior Member

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    Well, I am truly shocked! I just drove the car on a 40 mile round trip drive and it's very obvious that my battery is in FAR better condition now! It rarely got low and I was able to drive much further in my pulse and glides than before. I'd say about triple the distance. MPG's are too early to be conclusive. But I have no doubt that my battery will help my mpg's immensely. Look at the photos for a before and after the battery conditioning! It's pretty insane!
    Capture+_2020-10-13-12-26-41.png Capture+_2020-10-27-15-17-45.png
    Before the conditioning, my battery was measured at a low of 36% life expectancy and warning to replace it soon. After conditioning, it says we are now at 98.5% battery life expectancy and that it's like a new battery! During the test, it was pretty obvious that there was a huge improvement. Before conditioning, the test would end with still 350-400 seconds remaining on the Dr Prius test countdown, with the battery draining very quickly. After the recondition, the timer went all the way to 0, then asked me to continue to wait, and I waited another 5 minutes after the countdown ended before the battery was finally drained! Took forever to drain the battery! Pretty remarkable. I truly believe this was the culprit all along to my poor mpg's. It's just odd that it seemed to happen overnight from 48+ mpg's to 42-mpg's after doing all the maintenance on my car. Very coincidental that my battery must have reached a point of noticeable degradation at that exact same time. But again, will report my new mpg's in a week or so after at least 2 tanks of gas.....
     
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  3. douglasjre

    douglasjre Active Member

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    Check LTFT. It'll b over 12% confirming the intake air leak. Also you have an air bubble in the top of the black coolant hose.
     
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  4. FriedCells

    FriedCells Junior Member

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    Just an update for anybody that may have similar issues in the future or has ideas for me. My problem is not solved. :cry: After 3 tanks of gas, I'm still averaging 42-43 mpg's. It's slightly better than what it was because of the battery reconditioning. But still not where it should be. I did a test drive today, 10 mile test drive that was 5 miles on the highway and 5 miles through town, making a circle back to same position. I did this in my car (157,000 miles), then in my sister's 2015 Prius (approx 120,000 miles). I checked that oil level was good in both, tires at same pressure, both HV batteries near top bar, reset trip meter. I got 54.5 mpg in her car. I got 47.1 mpg in my car. I've tested her HV battery and it's at 65% capacity, while mine is now at 98% capacity. The only reason that I was able to keep my mpg's fairly good was because I was able to get quite a bit of extra distance from my battery compared to hers. But the highway portion of the test, getting to the stop sign off the ramp, hers was 60mpg at that point and mine was 45mpg. On both, I accelerated quickly up to 70mph displayed, then Cruise Control until exit. On both return routes, I hit about 5 of the 10 red lights, not much difference there. But I did notice that accelerating in her car from a stop seemed to affect her mpg's far less than in mine. It wasn't easy to lower her mpg's. Mine drops quite quickly when I accelerate from a stop. Quite a noticeable difference. @douglasjre mentioned LTFT showing sign of an air leak. Mine does seem higher but not by so so much. How would I find the source of the leak? When I did all the work on my car, I replaced the gaskets connecting anything to intake manifold with new gaskets. I've taken this apart 3 times now looking for any issues. EGR pipe gasket is good on both sides also. Everything screwed tight. Did not lose gasket on either side of EGR cooler. Placed back in position without issues. Only bolt that I didn't replace is the very hard to get to one on the underside of the EGR cooler that I believe just mounts it to the engine block as I saw some other people recommend this. My K&N filter is clean, airbox closed properly. I've taken apart my OCC install 3 times, sealing it to obsessive levels by the 3rd time. The PCV valve came with some kind of thread sealer already on the threads. Originally used fuel line hose along with some brass plumbing fittings for all the connections in the PCV-OCC-Intake series, using screw type clamps at every connector and screwing down tight. After poor mpg's, thought maybe I accidentally cut a hole in a hose. Did everything all over again with new hoses. No change in mpg's. Thought maybe the rubber hoses were heating in the engine and collapsing, not allowing a good flow. So I bought stainless steel heater hose like for a hot water heater. Hoses are solid as can be and this time, I bought connectors that thread into those hoses, used permanent loctite at each connection to be sure of no air leak. The intake and outflow from the OCC got loctite on them too. Dipstick on OCC got loctite too as I don't use it. Sealed every possible place for air leaks. Only thing that I couldn't loctite was the main body that you open to empty the OCC. But it has very tight threads and a thick gasket. I really don't know what else to do at this point. Anyways, here's a video showing the side by side comparison of my sister's car (left) vs my car (right):

    Very disheartened as all the work that was supposed to help my car has cost me months of researching, countless hours of testing, countless hours of doing and undoing things, massive loss of mpg's over the last 7,000+ miles. I'm about ready to get rid of the Prius and make stupid payments on an electric car so I never need to look at an engine again!
     
  5. FriedCells

    FriedCells Junior Member

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    Just so you know what are the gauges starting from top left:
    LTFT (Long Term Fuel Trim)
    STFT (Short Term " ")
    Small ones : Coolant Temp and below, MAP Psi
    EGR Step
    AFR(c) (Commanded Air Flow Rate)
    FSS1 (Fuel system status)
    EGR%
    AFR(m) (Measured Air Flow Rate)
    Small ones : MAF gm/sec and below Target Air flow ratio
    Speed
    RPM's
    Small ones : WP duty (water pump usage) and below not functioning
    Fuel Flow - gal/min
    Small ones : Throttle position, then far left, Fuel pressure (not working) and below O2 sensor Equivalence ratio
     
  6. FriedCells

    FriedCells Junior Member

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    Not sure why her EGR didn't show anything for the first minute or so. Maybe glitch? Also noticed her FSS1 would go down to 0, mine always at 1 or higher. Not sure what that means.
     
  7. Peter123

    Peter123 Active Member

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    When you first start the car, all the smog controls are open loop on safe settings. The EGR will not turn on until the computer goes closed loop and starts measuring and adjusting for the measurements.
     
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  8. royrose

    royrose Senior Member

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    This makes me wonder whether the reconditioning has resulted in a "false top" giving you a reading of 98% capacity while your battery is actually still performing poorly, if that makes sense. Or that your battery has some sort of problem not reflected in the capacity number.
     
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  9. FriedCells

    FriedCells Junior Member

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    Definitely not a false positive. Before reconditioning, my battery would drop almost instantaneously. Now, I can go at least triple the distance on battery alone than before. It's quite an obvious and amazing result. Before, it would skip from full to empty in seconds, without dropping bars one at a time like it should. Now, I can actually see each bar passing and they each last a long time. It actually takes quite a bit of effort, time and pulse and glide to get my battery to drain now. And during the comparison with my sister's car, I was able to go quite a bit more distance on battery alone than her 2015 battery with less miles. The reconditioning was a great success. I used to get 48-49 mpg's with a degraded battery. After all my maintenance, dropped to 38-42 and lots of effort to get 42. Now, after battery recondition, I'm consistently at 42-44. It's better but something is still not right. But it ain't either battery.
     
    #69 FriedCells, Nov 8, 2020
    Last edited: Nov 8, 2020
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  10. FriedCells

    FriedCells Junior Member

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    Since you seem to know about these things, would you mind looking at the video that I posted above? (Full screen, change settings to 720P and it's clear). Compared to my sister's car on the same route, she got approx 8mpg better than I did. That's about the mpg's that I've lost during the maintenance that I did. At similar speeds/RPM's, our MAP and MAF and throttle positions look fairly identical. If there was a leak somewhere, wouldn't one of those numbers be different? The only number that seems different is the fuel trim numbers. With that info about MAF, MAP, etc, is it easier to narrow down the problem? Maybe a failing fuel injector? Fuel pump? Please help :(
    For example, at about 3:16 into the video, you can see at a similar moment, all the numbers are about the same, except LTFT. Wouldn't something else like MAF be off if there was a vacuum issue? I'm not a mechanic, just guessing here:
    Screenshot from 2020-11-08 13-31-28.png
     
    #70 FriedCells, Nov 8, 2020
    Last edited: Nov 8, 2020
  11. FriedCells

    FriedCells Junior Member

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    @douglasjre @Peter123 @royrose @ASRDogman @Mendel Leisk ... I finally got around to checking some more things on my list of things to check including rear wheel rotations for brake drag, spark plug gaps, O2 sensors. All those things checked out good. BUT.....one of my spark plugs is quite different than the others. Look:
    IMG_20201112_131931.jpg
    I took them out the way the engine is when you are facing it, so they are pictured exactly in order of the cylinders. These plugs have 25,000 miles on them. The 3rd one has a dry black carbon build up on it. Very different than the other 3. Although the 4th has more oil than the other ones. So, from what I've read, it seems that I may have a bad (leaking) fuel injector on that cylinder running rich. Now, I listened to each injector with a mechanic's stethoscope and they all had a nice crisp, even clicking sound. Anybody want to confirm my suspicions? Does it make sense that one fuel injector is failing since only 1 plug looks like that? If I was running rich from some other cause, like vacuum leak, or whatever, all plugs would look similar, right?
     
  12. cnc97

    cnc97 Senior Member

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    Either the injector is the culprit, or the coil is failing on that cylinder. The carbon fouling is “wet” looking rather then dry. The wet look leads me to believe that it’s a lack of ignition, instead of over fuel.
     
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  13. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    Yeah to my uneducated eye the plug looked shiney too.
     
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  14. FriedCells

    FriedCells Junior Member

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    Thanks for the answer. My mpg has been lower and using torque has shown my Long Term Fuel Trim has been too high, running rich. I felt the black part of the plug with my finger and was very dry. Took a wire brush to scrub off the black. It was dusty and caked on like carbon. Maybe the light makes it look shiny, but it was bone dry. I took out my fuel injectors, bench tested them with a 9V battery and ran carb cleaner through them. They all function perfectly, good spray pattern, open and close perfectly. I really thought that would be the culprit, but no luck. I also tested resistance on spark plugs and ignition coils. They are also all within spec. One thing that I thought maybe was causing the rich condition was a failing upstream O2 sensor. Based on a test that I did between 2 Prius's, I could see that my O2 sensor didn't fluctuate Voltage nearly as much. So I went ahead and got a new one. And now I have a much bigger problem. P3190 code and car won't run! Going to start a new thread on this as it's now a new issue. Been testing things for 2 days now, reading like crazy, not working, trying to figure this out....almost in tears. So frustrated.
     
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  15. FriedCells

    FriedCells Junior Member

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  16. Abarnabe

    Abarnabe Member

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    You replaced the cvt transmission oil, according to toyota the oil level should be 1cm lower than the fill hole, but many people keep filling until it spills out. Too much oil causes foaming and increased friction. Regarding the traction battery you can recondition it with a 255vdc 50 dollars charger HLG-80H-C350A
     
    #76 Abarnabe, Nov 14, 2020
    Last edited: Nov 14, 2020
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  17. FriedCells

    FriedCells Junior Member

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    Good info about the tranny oil. But
    Good info about the tranny oil. But my mpg was just fine after changing that oil. It wasn't until I did the EGR cleaning, OCC addition, and other stuff 1000+ miles after the tranny oil that I lost mpg's overnight. Didn't know about the 255vdc charger option. Already bought the Prolong system. But that's good to know.
     
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  18. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    The Toyota spec is 0~10 mm below lip of fill hole (with car level), so filling till it starts spilling back out is a good way to do it.

    Just on a phone now, will post Repair Manual excerpt later, if I can get a chance...
     
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  19. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    Here's the Repair Manual info:
     
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  20. Grit

    Grit Senior Member

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    Way cheaper than those prolong grid chargers that are over priced :cry:
     
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