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Rebuilt the Engine; Won't Go Now???

Discussion in 'Gen 4 Prius Main Forum' started by PaulHeiser, May 14, 2023.

  1. PaulHeiser

    PaulHeiser New Member

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    I had the common heater exchange coolant loss on this car, but I never heard of it before now, so I misdiagnosed it of course.

    The car only has 155,000 miles on it, but the coolant was definitely blowing out of the exhaust on the highways...and then overheating.

    I changed the head gasket, and drove it, but of course the problem was the same.

    Then I disassembled the engine, took the block and head to a machine shop, and neither was failed their tests. I was stunned, and then I found the research online about the heater exchange issue. I did the common heater exchange bypass on it, and the problem was solved.

    However after I rebuilt the engine and installed it, it won't go now. I also suddenly have a whole list of DTC codes now.

    Can anyone help me on these?

    P3190: Poor Engine Power - DTC Severity 2 of 3 - Repair Immediately
    P261B: Engine Coolant Pump "B" Control Malfunction
    P261C: Engine Coolant Pump "B" Control Circuit Low
    C1A50: Brake System Malfunction
    B1423: Open IN Pressure Sensor Circuit /Abnormal Refrigerant Pressure
    C1259: 1. EV Control System Regenerative Malfunction, 2. HV System Regenerative Malfunction
    C1A63: Accelerator Sensor Malfunction


    I'll appreciate any help. I need to get this car running now...or really last week. :(
     
  2. bisco

    bisco cookie crumbler

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    what are you reading the codes with? does the car enter ready mode?
     
  3. PaulHeiser

    PaulHeiser New Member

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    It's a Zurich scanner. The car doesn't enter ready mode. It says not ready to drive and won't start.

    When I erase the codes with the scanner, it will start for about 10 seconds. Then the ECU shuts it down.

    I'm going to start by cleaning out all of the intake; EGR, Manifold, Throttle Body, Injectors, Head Intake Ports, and then reset the ECU. I think some junk just got unsettled in there when I tore the motor down, and when the ECU reset while being off the battery, it has no more statistics about the previous flow rates through the intake pipeline. So I gotta get it back to manufacturer specs by cleaning it out I assume.

    But I really am just looking up the codes, finding out what they mean, and then researching online to see what I can try to do by trial and error.

    I am hoping to get a bit of an advanced insight from this forum. I'm going to specialize on Priuses from now on, so it would be a significant lesson for me. Thanks
     
  4. PaulHeiser

    PaulHeiser New Member

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    It's weird because I took off the intake manifold, and it looks clean. PCV valve rattles well too. I think it's a waste of time to pull of the EGR stuff.

    I'm thinking that the electronic throttle body or the throttle position sensor is out of wack with the ECU. I was pushing on the butterfly blade before reassembling before, and I didn't know that's not good for the positioner. But the throttle body is clean.

    I think it would be unlikely the TPS is bad on a 2017 with 155K mi.

    To be honest, maybe I didn't get the timing chain lined right, so I'll dump that oil to pop off that cover.


    If anyone has any thoughts on any of the above DTC codes or engine swap/rebuild type situations, please chime in.
     
  5. rjparker

    rjparker Tu Humilde Sirviente

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    Rebuilt the engine? Or just the head gasket twice?

    It never started. Thats just mg1 spinning it at 1000 rpm for 10 seconds.

    I bet the maf is dirty or you have a cable partially unplugged. I would start at the water pump.
     
    #5 rjparker, May 17, 2023
    Last edited by a moderator: May 17, 2023
  6. PaulHeiser

    PaulHeiser New Member

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    On the first round, I switched the head gasket. On the second round I broke down the engine to take the block and head to a machine shop where everything proved to be unwarped/uncracked. Never was actually "rebuilt" with all new rockers, bearings, rings...only new head gasket.

    I cleaned the MAF with the MAF spray, and that didn't improve anything. After I reassemble everything, I'll do it again.

    I'll check the whole wiring harness to be sure.

    What if the hybrid battery goes too low? It doesn't matter, right? Because I only need to get the gas motor to run, and that will charge it up, and some of those codes will drop off with it charged, eh.
     
  7. rjparker

    rjparker Tu Humilde Sirviente

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    It does matter. It is required to spin the engine at 1000 rpm for 10 seconds to start it. So minimize the attempts by getting help if you need it. Once the engine starts it will charge the hybrid battery.
     
  8. bisco

    bisco cookie crumbler

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    you'll need a charger if you discharge the battery too far, and tech stream might help nail down the codes.
    is the 12 volt healthy?
     
  9. PaulHeiser

    PaulHeiser New Member

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    IMG_20230517_110522921.jpg
    The 12 volt battery is fine, and I don't know how much is left in the hybrid battery.

    I found all of the intake camshaft rockers knocked off of the valve springs when I pulled off the cam cover. Does anyone know what caused that one? Probably timing chain not lined up right, eh?
     
  10. PaulHeiser

    PaulHeiser New Member

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    I checked around online, and others are saying that their rockers came off because timing jumped a tooth. I'm taking off the timing chain cover now to probably see that.

    My problem was when I was doing the timing chain in assembly, I couldn't get the crank alignment mark to line up at the right spot for the chain. It's like there is a block right there at the 3 O'Clock position where the crank mark should be set. I got it as close as possible, and I thought the teeth were going to grab a chain at the right spot after all.

    Does anyone else ever have that problem with the crank not lining up right because of a block when trying to turn it?
     
  11. PaulHeiser

    PaulHeiser New Member

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    I noticed that the valve springs are looking bent off from each other a little. I expect to see bent valves when I pull cam carrier and head off.

    I'm not sure what cause was:
    1. Crank and Pistons not assembled right?
    2. Timing chain not aligned?
    3. Maybe I bent a valve a little bit off when I practiced removing one with an over/under valve spring clamp, and that threw things out of wack???

    The valves definitely had to have collided with the pistons to knock off a whole row of rockers arms, and it's only on the intake side and not the exhaust row.
     
  12. rjparker

    rjparker Tu Humilde Sirviente

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    Not good. I would get another head.

    While not a gen4 this video might help. There are marks people mistake as the timing marks but are not.

     
  13. PaulHeiser

    PaulHeiser New Member

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    I saw that one.

    The thing for me was getting the crank to go a full rotation in order to get it lined up to the pink chain mark..

    Now I can turn the crank full rotation now, but for some reason... Wait, maybe when I couldn't get it to rotate before, the pistons just happened to be colliding with the open valves. That makes the most sense. Now the crank fully rotates because no open valves are in their way.

    Wow, what a lesson in automotive mechanics. Sheesh.


    Where should I get a new valve kit from? I see autozone and oreilys don't have these things like most things I have looked for.
     
  14. rjparker

    rjparker Tu Humilde Sirviente

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  15. PaulHeiser

    PaulHeiser New Member

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  16. PaulHeiser

    PaulHeiser New Member

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    IMG_20230517_213240168.jpg Just to wrap up this thread...

    Those are the damaged intake valves on the top row in the pic. The exhaust valves are on the bottom row, and they are still sitting flush to the head surface. The stems on the upper row are bent, so they won't sit flush anymore. They won't seal now.

    One thing you can do to check this problem is peak into the intake ducts with the intake manifold off, and you can see if there are gaps between the valve valve plates and their valve holes because they won't sit flush with the head surface anymore. If the sit flush, then they're closed, and it's probably not a problem. You can also send an endoscope down into the spark plug openings with the plugs removed.

    The water test is where you pull off the head, and you dump water into the manifold ducts. With the valve springs still on...those valve plates should hold the water in the head. If they leak at all, it's a fault.

    And you need to do the water test when you seat or "lap" the new valves into place. You use a drill, a piece of rubber tubing, and some lapping compound to grind the valve plate into the valve seat until they are perfectly reciprocated with each other.

    I checked around the salvage yards, and I didn't find any used valves. They basically only sell the whole motors or nothing at all. Dealerships quoted me $17 each valve and $42...and two days to ship to their parts depts.

     
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  17. PaulHeiser

    PaulHeiser New Member

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    The engine runs fine now. I replaced all intake valves and lapped them.

    The problem was that I didn't line up the timing correctly. The video examples and the ALLDATA diagrams showed me an intake camshaft differently than what I was looking at in mine. I used deductive reasoning based on what everyone was showing me, and that was wrong. I actually used the wrong mark on the intake camshaft. Therefore that made it 1/8 of a turn out of rotation, and that slammed the pistons into the valves. Bending valves is not so uncommon I discovered during research especially in the high performance field.

    I didn't have any problems with the valve guides either by the way, nor seating the new valves in, nor getting a good water test seal for the seat fits.

    I had a lot of error codes that came up before, but they all cleared up after engine was running and driving again.
     
  18. rjparker

    rjparker Tu Humilde Sirviente

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    Congratulations!

    Victory.jpeg
     
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  19. PaulHeiser

    PaulHeiser New Member

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  20. ChapmanF

    ChapmanF Senior Member

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    For anyone else following along at home, for those times when you are reading about ways of access to the first-hand Toyota repair manual, and wondering whether even $25 sounds like too much to spend ...

    Toyota Service Information and Where To Find It | PriusChat

    ... compare it to an estimated cost for what you have just read here.