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Gremlins after Brand New HV battery swap...Help?

Discussion in 'Generation 1 Prius Discussion' started by Nine44, May 31, 2022.

  1. Nine44

    Nine44 Junior Member

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    I just replaced my HV with brand new from Toyota here in Cincy. Didn't realize that I had to get into the new battery and swap the computer,etc , but after a few hours, I was back up and running. Started it up, red triangle disappears and I took it for a lengthy test drive (20 mi) and everything worked great--'till the next morning.

    Next day, I went to start it up. Engine runs for about 10 seconds, sounds like it goes under load then dies (not smoothly). Does this over and over. After a few days of sitting it continued to do the same thing--until, out of desperation, I tried putting it in gear during those 10 seconds of engine running. Car moves a little, engine keeps running. No problems since. Anyone have any ideas on what happened?
     
    #1 Nine44, May 31, 2022
  2. AlexY

    AlexY Member

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    Search for throttle body cleaning procedure, quite common in gen 1 but your circumstance is odd.
     
    #2 AlexY, Jun 1, 2022
  3. Nine44

    Nine44 Junior Member

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    Forgot to mention--I did see that and cleaned the throttle body and mass air flow sensor to no effect.
     
    #3 Nine44, Jun 1, 2022
  4. dabard051

    dabard051 Tinkerer-in-Charge

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    There are multiple reasons for the Red Triangle of Death.... did you read the fault codes with an OBDII reader?
    what was the fault code that led you to replace the HV battery pack?

    Your last sentence: "I tried putting it in gear during those 10 seconds of engine running. Car moves a little, engine keeps running. No problems since." implies that the problem is no longer present. Is this true?

    Thinking about what connectors &tc get moved around when the HV battery pack comes out/goes in, my first reaction is that the problem was NOT due to the HV battery swap.

    Next thought would be a bubble of water in the fuel line (did it rain between day 1 & day 2?) that caused the no-start problem. That you put it in gear. and then it kept driving is a possible scenario.

    Anyway, some thoughts as to what MIGHT have happened.
     
    #4 dabard051, Jun 1, 2022
  5. AlexY

    AlexY Member

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    You should get interface and techstream, there would be codes for reason why engine didn't start but I'm pretty sure throttle is not cleaned properly, especially if it fail when it is cold, under around 10°C (50°F).
     
    #5 AlexY, Jun 1, 2022
  6. Nine44

    Nine44 Junior Member

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    Update: After this weird series of events, my mileage has dropped to mid-upper 30's. I was getting 51 on average with the (bad) battery. City seems especially bad. I'm not convince that my brake regen is working. Would I get a code for this if that was the case?
     
    #6 Nine44, Jun 20, 2022
  7. Trombone

    Trombone Member

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    Seriously doubt that the car was getting "51 on average" mpg! This is not typical for the Classic, based on my 20+ years of driving the '02. Don't know how you figure your mpg, but don't trust the MFD read-out---do the math with the odometer at the pump for the most accurate numbers.
     
    #7 Trombone, Jun 20, 2022
  8. Nine44

    Nine44 Junior Member

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    I do the math each time. I do a lot of 40 mph driving, so my "average" may not be your average. Any thoughts on the actual question?
     
    #8 Nine44, Jun 20, 2022
  9. BiomedO1

    BiomedO1 Senior Member

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    From what your describing; this seems to be an ICE issue - but without error codes; it's very difficult to nail-down online. I would focus on basics - air; spark, compression, and exhaust. I'm going to assume extra high mileage so check your exhaust and CAT. Motor may be constipated, exhaust blockage. Low compression due to worn-out engine. Bad upstream O2/mixture sensor - sometimes this won't throw a code; just get very crappy mileage - ditto with a bad MAF sensor. You could have bad injectors or fuel pump. Check your fuel pressure at the fuel rail check valve. I'm not going to bother with spark plug and ignition coils - if you can do most of those things above; I'm going to assume you know how to check and troubleshoot those. Try running a can of CAT safe concentrated injection cleaner through your gas tank.
    But before throwing parts at this problem; get the codes read. You should at least see a P0300 in the history; when the car wouldn't start.

    Hope this helps.....
     
    #9 BiomedO1, Jun 20, 2022
    Last edited: Jun 20, 2022
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