Transmission Jerking Badly in ECO Mode

Discussion in 'Gen 3 Prius Main Forum' started by dc101, May 10, 2021.

  1. dc101

    dc101 Junior Member

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    Thanks everyone. I plan one opening EGR this weekend and doing clean up. Is it too late already? Not sure sometimes it works without any issues. The coolant level goes down but then stays at certain level. If open coolant bottle cover, I hear and feel pressurized lead of air.
    Is my engine dead or Head Gasket can be repaired?

    Is cleaning EGR valve worth it?
     
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  2. Mendel Leisk

    Mendel Leisk Senior Member

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    Are you sitting down...

    with those miles, likely IS to late. Doesn’t hurt to clean the EGR , but I’d address the head gasket ASAP, and then the Exhaust Gas Recirculation right after.

    a leak down test, performed by someone who knows what they’re doing, is best for diagnosing head gasket issues.

    Full disclosure: I’m just an arm-chair mechanic, relaying what I’ve read. Have done the EGR cleaning though.
     
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  3. rjparker

    rjparker Senior Member

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    First - is it an oil burner, has the hv battery been replaced, has the brake actuator been replaced and or has the inverter been changed?

    How long would you like to keep the car?

    Obviously you have been driving close to 30k miles a year, are you still putting on the miles?
     
    #23 rjparker, May 14, 2021
    Last edited: May 14, 2021
  4. Mdv55

    Mdv55 Active Member

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    This. Find the source of the misfire and pull the plug for cyl 1. Is it wet, cylinder shows evidence of coolant? Leak down test to confirm if not obvious. If you have a leak, that needs to be fixed first, complete clean of EGR system and intake manifold should be done if you're going to keep the motor. If it burns a lot of oil and/or you're looking at keeping the car for a long time an engine swap might be better then a headgasket repair.

    Sometimes, especially if you don't live in a hot environment, leaving the cap on the coolant bottle a little loose lowers the pressure in the system enough to reduce the coolant leak into the cylinder. You're on borrowed time with that method though. It could improve driveability but you still have a problem that needs to be fixed.
     
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  5. dc101

    dc101 Junior Member

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    I have been working on EGR removal and now cleaning since morning. It is completely clogged - Cooler, EGR valve, tubes are crusty. Seems like it is too late for all this. I also viewed a few YouTube videos, an P0301 and engine shaking at the startup are clear sign of head gasket failure at cylinder 1. My symptoms have been different though. It does not shake at startup every time. Initially it drove fine in "B" position. I will report tomorrow.
     
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  6. Mdv55

    Mdv55 Active Member

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    Pull the plug and inspect/leak test.....

    Everything else is internet speculation. The above will help define what is really going on.

    It doesn't matter if your symptoms match exactly or not.

    Given the EGR situation it's highly likely you have a head gasket issue at this point.
     
  7. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah at your miles that the norm. Pathetic design, we were the guinea pigs. :mad:
     
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  8. rjparker

    rjparker Senior Member

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    Shake is sporatic with hg. Depends on the position of the piston and valves. Many go weeks between shakes until it goes really bad. Engine time is the frequent result.
     
  9. wheezyglider

    wheezyglider Active Member

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    You probably got this, but make extra sure you get the EGR passage through intake manifold. It feeds the little hole in each cylinder port, people miss those sometimes...
     
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  10. tvpierce

    tvpierce Senior Member

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    What do you mean by this?

    Earlier you said the coolant "stays in the middle". Are you adding coolant regularly?

    As stated earlier, it's not likely a transmission problem. Frankly, your description of the original problem had me thinking it might be a faulty ignition coil -- that would account for it happening only when it got hot. But since you didn't have a check engine light for a misfire, I figured it was something else. Now you have the P0301 code which is a misfire on cylinder #1. If I were in your situation, I'd swap the coils on cylinders 1 & 2, reset the codes, and see if misfire moves to cylinder #2.
     
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  11. Mendel Leisk

    Mendel Leisk Senior Member

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    Or swap coils 1 and 4? More conclusive, because sometime the failures are between 1 and 2, might affect both.
     
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  12. dc101

    dc101 Junior Member

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    While I am still cleaning EGR cooler, I want to report that I pulled plug 1 and it was dry with no residue and/or oil on it. After I install the new plug, I will swap coils 1 and 4 (was thinking of doing 1 and 2 however great suggestion to keep them apart).

    I am still less optimistic because of all other symptoms, but with an encouragement from this Prius Chat Experts here, I will continue my efforts until we conclusively establish that it is head gasket. More to report later in the day.
     
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  13. Mdv55

    Mdv55 Active Member

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    That's a really good sign!
     
  14. dc101

    dc101 Junior Member

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    Update: I finally completed cleaning of EGR cooler, EGR valve and passages. I also replaced spark plug on cylinder 1 with a brand new NGK plug, swapped ignition coils between cylinders 1 and 4. So far the car has been driving fine without any glitch es. I momentarily turned on ECO mode and it was Ok. I test drove in regular mode both in stop n go traffic and also on the highway (up to 60Mph). So, far no problems. Engine would startup up fine on traffic lights. I will drive it more tomorrow, as it was exhausting day.
     
  15. tvpierce

    tvpierce Senior Member

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    Well done. Did you clean the small EGR ports in the intake manifold?
     
  16. dc101

    dc101 Junior Member

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    On the intake manifold, where the red gasket is I cleaned the hole. It was crusty as well. Ideally intake manifold needed deeper cleaning as well, however, I was so exhausted with unknown probability of success, I didn't go too deep. I have added coolant to the reservoir as well and will observe how things go - gremlin might be still sitting there.
     
  17. mikey_t

    mikey_t Active Member

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    Each port of the intake manifold has a small hole along the bottom for the exhaust gas to flow into the engine and those get badly plugged. If you didn't get to those, I'd suggest to do that next time you have some time. It shouldn't take long to remove, clean, and put back. I did it a few weeks ago along with replacing my PCV valve. I just thoroughly sprayed carb cleaner into each hole, moving the nozzle in circles until I felt good about it. Then placed it on it's side so the crud could come out and the manifold could dry.
     
  18. dc101

    dc101 Junior Member

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    I noticed slight short duration misfire/shake behavior today at a few traffic lights, while try to accelerate from full stop (about twice during my test trip), but generally I drove over 50 miles without any major issues. I guess it depends where the engine piston was in cylinder 1 when it stopped at light (assuming cylinder 1 is most susceptible to head gasket failure. No check engine lights on though.

    Thanks for the the tip on intake manifold. I didn't know about that at all - I will take the manifold out this week and clean up the and take care of it - seems like a pretty involved task as throttle body needs to be removed.. I will update as I get to the it.
     
    #38 dc101, May 17, 2021
    Last edited: May 18, 2021
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  19. dc101

    dc101 Junior Member

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    Is there a way to test the radiator fans as I turned on the AC and noticed that only driver's side fan turns on (a little squeaky though). The other passenger-side fan never turned on during test. I would imagine with AC on both fans should be running.. Just trying to eliminate fans as potential source of overheating.
     
  20. ChapmanF

    ChapmanF Senior Member

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    Yup, you've tested them, they didn't pass. The circuit is designed to always run both fans together, either both at low speed or both at high speed, never just one or the other.

    A look at the wiring diagram shows what the possible causes can be depending on which fan is running and which one isn't.
     
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