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Why is the engine not getting any gas??

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by D-23, Aug 29, 2012.

  1. D-23

    D-23 New Member

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    I have a 2005 Toyota Prius I purchased Salvage from an insurance company and (without any hybrid experience what-so-ever) have gotten a bit over my head with it. Long story so cutting to the chase, current issue: All signs show the car's engine isn't receiving any gas. I started looking for the fuel pump but wasn't having much luck. I know what a typical fuel pump looks like and found nothing of the sort. I started taking the fuel tank down to get a better insight on the matter but it got dark so I left the job unfinished. As I started researching more into it, I'm not finding any information on fuel pumps for this generation Prius?? Looking up Car-Part.com--Used Auto Parts Market for example, they'll list a fuel pump for the 2001-2003 generation, skip the 2004-2005 and go right into 2006-2009. Is there no fuel pump in a 2005 Prius?? And if not, what system is being used to deliver the fuel? If the engine isn't receiving fuel, where should I be looking? Any helpful insight will be appreciated, thank you!
     
    #1 D-23, Aug 29, 2012
  2. cwerdna

    cwerdna Senior Member

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    #2 cwerdna, Aug 29, 2012
  3. D-23

    D-23 New Member

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    Thank you for your concern but I guess I just ran into my answer here on these forums:
    the gas bladder: exposed! | PriusChat

    The fuel tank is inside the fuel tank and it's so complicating that honestly it'd be cheaper and quicker to simply replace the entire fuel tank.
     
    #3 D-23, Aug 29, 2012
  4. cwerdna

    cwerdna Senior Member

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    The hybrid articles under AUTOMOTIVE TECHNICAL ARTICLES might be of interest. The fuel and evap system PDF describes the complicated fuel system and tank...

    I've met galaxee and her DH before. Her DH used to be a Toyota technician.
     
    #4 cwerdna, Aug 29, 2012
  5. D-23

    D-23 New Member

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    I've already reviewed the site and found it helpful as well but thank you very much!
     
    #5 D-23, Aug 29, 2012
  6. paprius4030

    paprius4030 My first Prius

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    If you got it salavage from and insurance Co., was it in an accident? If it was in an accident maybe the switch got tripped that shuts off the pump in an accident.
     
    #6 paprius4030, Aug 29, 2012
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes, if you are sure that the fuel pump is not operating. I suggest the first check would be to apply 12V to the fuel pump and see whether you can get the pump to run. If yes, then the problem is elsewhere.

    This assumes that you have access to the Prius electrical wiring diagram and the repair manual so that you can figure out where to find the fuel pump connections. The circuit opening relay provides 12V power to the fuel pump. This relay is part of a large integrated assembly that contains four separate relays.

    Note that the relay coil receives power via the IGN fuse and is switched by terminal FC of the engine ECU. The relay switched terminals receive power via the EFI fuse and EFI M relay.

    So if you verify that there is power at the EFI and IGN fuses, verify that the EFM M relay is passing current, and run a jumper from terminal FC to ground so that the circuit opening relay will close, then the fuel pump should run.

    Good point, this switch is located on the inverter.
     
    #7 Patrick Wong, Aug 29, 2012
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  8. D-23

    D-23 New Member

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    This may be exactly what I need. I do not know for sure if it is the pump but this switch you're referring to, tell me where on the inverter is it and how do I know it's engaged. Yes the car was in an accident and if it turns off in an accident then it might as well be the case.
     
    #8 D-23, Aug 29, 2012
  9. Patrick Wong

    Patrick Wong DIY Enthusiast

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    This is called "circuit breaker sensor #1" in the Prius repair manual and is mounted on the side of the inverter closest to the driver's side fender, near the main relay/fuse box. I suggest you remove the wiring harness connector and use an ohmmeter to see whether the breaker measures 0 ohms or infinity. If it is open, use a paper clip to short across the wiring harness connector and see what happens.
     
    #9 Patrick Wong, Aug 29, 2012
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  10. edthefox5

    edthefox5 Senior Member

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    You also may be immobilizer mode which shuts off fuel to the engine.
     
    #10 edthefox5, Aug 29, 2012
  11. D-23

    D-23 New Member

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    Does anyone know which two wires are the positive and negative fuel pump connections when unplugging the socket wiring going inside the fuel tank towards the fuel pump? Anyone maybe with a detailed Prius electrical wiring diagram? Thank you
     
    #11 D-23, Aug 29, 2012
  12. D-23

    D-23 New Member

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    Thank you, I will most definitely look into it tomorrow. You wouldn't by any chance know which two wires are the positive and negative fuel pump connections when unplugging the socket wiring going inside the fuel tank towards the fuel pump? Or maybe know where I can come by a detailed Prius electrical wiring diagram? Thank you again!



    Read more: http://priuschat.com/threads/why-is-the-engine-not-getting-any-gas.114388/#ixzz24zLojWDh
     
    #12 D-23, Aug 29, 2012
  13. edthefox5

    edthefox5 Senior Member

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    It may not be pump. And not neccessary to know polarity when checking. Check if the car is presenting 12 volts TO IT. Plus or minus who cares. Not neccesary to know polarity when checking at this point. Leave the pump wires plugged in and shove your dc dvm probes into the wires. Or get thin wires to get into the conector. Hook probes to wires. Make car ready. See if you get 12 volts there. I bet you don't because I have never heard of a bad pump on 5 years here. Maybe one. But rare.

    But no 12 volts there the problem is upstream. Fuse. ECM. Immob mode etc.

    If you do have 12 volts there then the pump is bad. Easy.

    Btw, you have codes/cel's thrown too on the dash right? You need to know what codes are being thrown as that will tell you where the issue is.
     
    #13 edthefox5, Aug 29, 2012
  14. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Post #2 already suggested that you subscribe to techinfo.toyota.com so that you can access the EWD and the repair manual.
     
    #14 Patrick Wong, Aug 29, 2012
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  15. northwichita

    northwichita .

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    hobbit details of fuel pump wiring worth checking out.
    No Squirt

    I'm also curious about ---All signs show the car's engine isn't receiving any gas.
    Is there a simple check for this?
    ​
     
    #15 northwichita, Aug 30, 2012
  16. edthefox5

    edthefox5 Senior Member

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    Thats a good Hobbit. All the OP has to do is put the pos probe into the relay C/OPN output wire and measure to ground for 12 volts. Make the car ready and measure.

    Or he can measure in the relay box. Pull the C/OPN relay and measure to ground one side of coil for constant 12 post fuse. The other side of the coil is pulled to ground at the ECM to energize the coil. I'd be careful about manually pulling that to ground it might damage the ECM. if you have constant 12 What you can do is put a 12 volt test lamp in place of the relay coil and go into ready. If it lights the ECM is working.

    But if 12 volt constant on one side of coil and then the coil is not energizing in ready (relay clicking) the ECM is not pulling that coil low. It is being held to an immob state by airbag deploy or other or maybe damaged ECM.
     
    #16 edthefox5, Aug 30, 2012
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  17. D-23

    D-23 New Member

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    Unfortunately I've decided to find out the hard way. I took the fuel tank down, cut it open, and pulled the fuel pump out that way (I can already feel many of you bursting out with "Why would you do that??") but I did. The fuel pump seems to work when I give it a 12v from a battery but it doesn't seem to have enough power (comparing it from past experience with fuel pumps). It pumps but I almost want to say barely. I will be getting back to this Monday with a used fuel tank I am purchasing for $100 from a Junk Yard on my way to visit my in-laws for the weekend so we will see if that fixes anything.
     
    #17 D-23, Aug 30, 2012
  18. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Sounds exciting. How about posting photos.

    Now that you've done that, when you try to make the Prius READY, do you find 12V at the wiring harness connector leading to the fuel pump?
     
    #18 Patrick Wong, Aug 30, 2012
  19. Sergei Shek

    Sergei Shek New Member

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    So how did you end up getting this issue fixed?
     
    #19 Sergei Shek, Jan 22, 2019
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