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Random Misfire detected (p0300, p0301, p0302)

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by BeoLurch, Sep 29, 2021.

  1. BeoLurch

    BeoLurch Junior Member

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    Howdy All,

    Well, I finally got this car to start and stay on after changing the HV battery and 12V, but now it is misfiring and giving me codes P0300, p0301, p0302, and p3193 (the car has 6 gallons of gas). This misfiring started when I noticed someone had broken into my car and it looks like they put something in my gas tank. There was evidence of pink fluid by the gas inlet. I've put in Heet to help with anything that might be in the fuel tank, but I'm worried about my engine while trying to pass the contaminated fuel. It seems like it is misfiring worse than most vids I've seen with this problem, but I could just be a scaredy cat... It's loud and shakes the whole car even while I'm in it. I'll attach a vid so all of you can see what I mean.

    Should I let it run for awhile try to pass the bad fuel, or will that hurt my engine and new HV battery?

    Cheers~
     
  2. SFO

    SFO Senior Member

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    How many miles, and what has the maintenance history been like?

    Odd that the misfires are only on two of the cylinders. Have you visually inspected the plugs, and the coils for carbon tracking or oil?
    Heet won't help with much, and if it was just water that was in the fuel you would need to use quite a bit of it.

    Best to just remove as much of the fuel as possible, then refill with fresh gas. Running 6 gallons of contaminated fuel through the engine may not be the best idea, and would take quite a bit of time to process. How old is your catalytic converter, and is it OEM?

    Once you get the fuel out, inspect it for contamination, if positive you may want to run some PEA (aka techron) in the fuel. There are other additives that may be more effective at cleaning up the fuel delivery system, such as Kreen or B-12 Chem-Tool.
     
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  3. TMR-JWAP

    TMR-JWAP Senior Member

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    That HV battery is looking a little depleted on the MFD
     
  4. BeoLurch

    BeoLurch Junior Member

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    215k miles/w regular oil change and routine maintenance. I haven't done any coil, or spark plug inspections
    (still on my list of DIY things to learn to do), but I did replace the MAF sensor with a new Denso sensor. The cat converter is aftermarket part, it was put in after being stolen so just the middle of the assembly was replaced.
    Should have mentioned that the tank was empty when I put new fuel in. There was a tiny bit of that pinkish fluid at the bottom of the fuel tank evidenced by the siphon I put in while checking fuel level. There wasn't to enough of it to siphon, so I filled up with new gas. I think I'm going to siphon out the gas AGAIN and put new fuel in. Maybe what ever is in there will be easier to pick up with there being a bit of gas tank.

    Well, it is a new-refurbished battery from WA Hyrbid battery repair. They installed it as well and made sure that it was working properly after install. I'm not too worried it showing a low level on the MFD because im still getting 14.1V when the engine is running. It hasn't run at all since the new battery was put in (wasn't running before either) so might not have had a chance to calibrate. I've only tried starting it 3 times since the new battery was put in a month ago, because of how scary it sounds while misfiring.
     
    #4 BeoLurch, Sep 30, 2021
    Last edited: Sep 30, 2021
  5. SFO

    SFO Senior Member

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    Now would be a great time to swap those plugs if they are at 215k.
     
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  6. TMR-JWAP

    TMR-JWAP Senior Member

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    Step one may be to get some help from someone who is has some experience with a Prius. Maybe @PriusCamper is available. I think he's in your general area.

    You may be seriously overcomplicating this. Sparkplugs are significantly easier to replace than messing with draining a fuel tank, and they probably really need it.
    Why did you replace the MAF sensor?
    Any chance you put diesel in the car by accident? Most diesel is reddish in color....
    The 14.1 volts on the 12 volt battery has ZERO to do with the state of charge of the HV battery. Maybe that 'new refurb' battery from WA Hybrid is a POS. Regardless, you're showing one or zero bars on the HV battery SOC display. You're about to be F'ed, because the warranty isn't going to cover the battery if it's depleted due to your engine being unable to run. Read the warranty.

    They installed a rebuilt battery, yet the engine has never successfully started since they installed it? That's wonderful. They were laughing all the way to the bank.

    The best thing you could do right now is clean the heck out of the throttle body, install new sparkplugs, disconnect the 12v battery for a few minutes. Reconnect it and let the car reset itself back to factory default. The HV battery will show about 60% (default) state of charge so it will let you try to start the engine. Leave the intake air filter off and when you try to start it, have someone spray(ing) starter fluid into the throttle body while it's cranking. Use the starter fluid to keep it running while it injects the (potentially) contaminated fuel for a few minutes. Hopefully the fuel lines will clear themselves and then the fresh gas from the tank will reach the engine.
     
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  7. BeoLurch

    BeoLurch Junior Member

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    I have a tendency to do that! Especially when it comes to things I have little experience with.

    I didn't put diesel in it, but someone else might have! Damn them vandals and vagrants! I've never witnessed or been the victim of more crime than I have while living in the Pacific Northwest. It's beautiful here, but it's rough. We need Batman.

    The day my car stopped working I found it tampered with. Not only did they potentially put stuff in my fuel tank, but to add insult to injury they foam sealed my doors shut and clipped my 02 sensor (cat still there though) ! I went for a drive after that and got a couple miles before it started misfiring and engine stopped. I try starting the car a few times and the 12v battery dies on me... Once I get the car towed home I replace the 12v and checked the gas level, the tank was practically empty as I mentioned earlier and found the pink stuff around the gas inlet. Filled up 6 gallons. Still wouldn't start. Bought a scanner, it said to change MAF. Would have cleaned it, but there wasn't any cleaner available locally. I did this before the HV battery was replaced. The code went away after changing the MAF.

    I took the car to mechanic and they told me it was pulling the HV battery code, out of gas, and misfire codes. The mechanic told me they couldn't really diagnose the problem until the HV battery was fixed or replaced since the car wasn't starting.

    A few weeks later I get the battery replaced. After the battery is replaced the car turns on, but the intense misfiring happens. After troubleshooting for causes of misfiring I get recommendations to replace spark pugs, coils, clean the EGR and intake manifold, and to put Heet or B-12 in the tank. I've yet to read or hear about cleaning the throttle body as a suggestion, but I'll look into it. It never misfired or showed symptoms before the vandalism, but I can't say for sure that's what caused all this. It could have just been a coincidence that my car broke down the day someone decided to mess with it.
     
  8. TMR-JWAP

    TMR-JWAP Senior Member

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    Ok, so let's start with this. The 12v battery in your car is used to power up the 12v accessories like computers, lights, electric water pumps, etc. The HV battery is what spins the engine for starting. When your 12v battery died, or anytime you lose 12v power (like when swapping batteries) all the ecus in the car return to factory default values, your gas gauge also goes to one blinking dot until it calibrates itself. As the car is driven (and ages) some of these ecus have parameters that slowly change due to wear and tear, carbon buildup, etc. Throttle body position is one of these. The throttle body inner surfaces tend to get carbon buildup, which can cause the idle position of the throttle blade to change. That's ok, because the ecus adapt to this. Unfortunately, all that "adapting" is lost when 12v power is lost, so now the ecu is expecting blade position to be in the 'as new' position, but it may not be. This can prevent the car from starting, which is why it's a good idea to scrub the inner surface to eliminate the carbon buildup and let the blade actually return to the 'as new' position so it matches what the ecu is looking for.

    I'm curious about how you checked tank level?
    Your car does not have an EGR system.

    Who did you piss off that would mess with your car?
    Your gas lid needs to be released from inside the car. Did they pry it open or was the car unlocked?
    Unusual that you were able to buy a MAF sensor but the store didn't have any cleaner? weird...most parts stores have a dozen cans. For future ref, even AutoZone brake cleaner works like a champ if you have no other choice.
     
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  9. BeoLurch

    BeoLurch Junior Member

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    The siphon tube was dry after pulling it out of the fuel tank. except the very tip of the tube which showed the pink stuff. Ah, ok must have watched a different Prius get fixed! I would have figured that out eventually...

    It might have been unlocked because it wasn't pried open. I just chalk it up to some people being garbage.

    Must have been a freak incident, all the auto stores in my area were out of it. I could have waited and bought online, but I was anxious to find out if that was the problem, keeping my car from starting.

    I never looked up anything about Prius until my car broke down, it's been an interesting journey. Lots of trial and error at my expense, That would explain why it's reading empty even though it has gas. You did a good job explaining that. I'll look into this, thanks!
     
  10. SparkyAtLarge

    SparkyAtLarge Junior Member

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    Isn't the HV battery normaly empty when you first start the car?
     
  11. TMR-JWAP

    TMR-JWAP Senior Member

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    The HV battery is normally kept at ~60% state of charge during standard car operation. When the battery drops to about 42%, the engine will kick on to recharge it. You can see this in real time, if you have the car parked, put the car in ready mode and run the AC. The engine will go through it's normal warmup routine, then the engine will turn off. The AC compressor is powered by the HV battery, so the AC will slowly deplete the HV battery. When the MFD display drops to 2 purple bars (which corresponds to approximately 42-43% SOC) the engine will turn on to recharge the battery until it indicates three bars, which will then turn blue. The car will try to maintain the battery in the blue range.

    Keep in mind, the HV battery is what provides the power to spin the engine for starting, not the 12v battery like a standard car. This is why, if you deplete the HV battery, you're in trouble. You can't just go grab a battery charger to fix it.
     
  12. Justin B

    Justin B New Member

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    I have a very similar issue here.. any way to charge the battery during all of this?

    my story is very close to this one and I'm not sure what the issue is
     
  13. TMR-JWAP

    TMR-JWAP Senior Member

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    When the HV battery reaches ~42% SOC, the engine will start automatically to recharge the battery. This assumes the car is in READY and is functioning normally.

    Are you saying your battery is discharged and doesn't have enough SOC to start the engine?
     
  14. Justin B

    Justin B New Member

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    Having issues with getting the car going and because of this the battery isn't being charged