1. Attachments are working again! Check out this thread for more details and to report any other bugs.

ICE stopping rough and P0420

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by terramir, Aug 22, 2015.

  1. terramir

    terramir Member

    Joined:
    Aug 3, 2015
    318
    49
    2
    Location:
    Los Angeles
    Vehicle:
    2004 Prius
    Model:
    II
    Hi ,
    I do not know if the two are related, saying the emissions are not as efficient as they could be, but I noticed that the engine seems to have a hard time stopping almost like dieseling on older cars, and well also that code, the check engine light comes on after I fill my tank but goes away after about 50 to 80 miles off right now but still rough engine cut-offs could use some hints.
    terramir
    Ps: 174k miles estimated 04 prius
     
    #1 terramir, Aug 22, 2015
  2. CrazyLee

    CrazyLee Member

    Joined:
    Aug 3, 2014
    153
    24
    0
    Location:
    Muskegon, MI USA
    Vehicle:
    2004 Prius
    Model:
    II
    Dieseling comes from carbon deposits in the combustion chamber that are hot enough to ignite any left over fuel. I would find this strange since the fuel is cutoff at the moment you shut off the engine. So some fuel must be lying around in the manifold to ignite when you shut off the engine. Maybe that is why some people (with high powered cars) gun their engines at shut off, to flush out the left over fuel. This harder to do in a Prius, first put it into D, then hold down the brake, then gun the engine and quickly shut off the engine.

    First thing to do is pump in a tank of premium with lots of engine cleaners in it and run that and see what happens.

    If the run on continues maybe the intake may need cleaning. There lots of good tips on how to do that here on PC.
     
    #2 CrazyLee, Aug 22, 2015
  3. terramir

    terramir Member

    Joined:
    Aug 3, 2015
    318
    49
    2
    Location:
    Los Angeles
    Vehicle:
    2004 Prius
    Model:
    II
    ehhh I think I was not clear the dieseling happens at times when the computer turns off the engine, i.e. when it decides it does not need it not every time but let's say in mc donalds parking lot or at a red light it turns engine off car shudders for like two seconds the engine before my 1k roadtrip to get a second battery it was virtually undetectable turning off and on.
    terramir
     
    #3 terramir, Aug 22, 2015
  4. terramir

    terramir Member

    Joined:
    Aug 3, 2015
    318
    49
    2
    Location:
    Los Angeles
    Vehicle:
    2004 Prius
    Model:
    II
    If I already have a pretty full tank of gas, any bottle brand I could use? to clean my engine a bit? Also could switching to semi synthetic oil help the situation?
    terramir
     
    #4 terramir, Aug 23, 2015
  5. 69shovlhed

    69shovlhed Surly tree hugger

    Joined:
    May 13, 2012
    2,170
    748
    0
    Location:
    Delaware
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Premium
    you might try cleaning the throttle body. get a can of throttle cleaner from the parts store and a lint free cloth. spray the cleaner on the cloth and wipe down the throttle bore and the edges of the throttle blade. do not just spray the chemical into the bore which is what it says on the can. sometimes deposits around the throttle blade can cause odd performance issues.
     
    #5 69shovlhed, Aug 23, 2015
    valde3 likes this.
  6. terramir

    terramir Member

    Joined:
    Aug 3, 2015
    318
    49
    2
    Location:
    Los Angeles
    Vehicle:
    2004 Prius
    Model:
    II
    Ehhh noticed something else weird, sometimes when I accelerate My engine like goes into "overdrive" vroooooommmmmmm. like high rpm and this happens at like 15 to 35 miles an hour which is nutz.
    Anyone got any links on a howto clean throttle body?
    And anyone got any other hints about what might be going on here.
    Help, the battery issue I can fix with reconditioning the spare HV battery I got right now (350 bucks plus a cell or two on ebay I hope(one ordered so far)), and then maybe recondition my cells, but mechanical issues I gotta nip in bud b4 they get expensive!.
    terramir
     
    #6 terramir, Aug 24, 2015
  7. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    7,764
    3,932
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2007 Prius
    Model:
    N/A
    Terramir is correct when he uses the word seems, as I do not believe his motor is dieseling; only seems like it is.

    My car does this from time to time as well, and I have got over worrying about it. It will typically do this when still warming up and not kicked over to stage 4. Once it is in stage 4 it shuts off and restarts seamlessly again. I don't know why it does it, only that it does and now I just accept it as something it does.
     
    #7 dolj, Aug 26, 2015
    Last edited: Aug 26, 2015
  8. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    7,764
    3,932
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2007 Prius
    Model:
    N/A
    If this happens soon after start up, it is probably is that you have pressed down on the "go" pedal while it is in stage 1 of warm up and forced it into stage 2. It behaves exactly as you describe in this situation.

    Try driving a little gentler until it moves on to stage 2 before requesting power if you can.

    If you want to read more of the 5 stages of Hybrid Warm up, click on the second link in my sig.
     
    #8 dolj, Aug 26, 2015
(You must log in or sign up to post here.)