New head gasket, now P0340

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by ZX Nutt, Mar 25, 2021.

  1. ZX Nutt

    ZX Nutt New Member

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    I'm working on the wife's 2012 V. At 151k, she had the violent shake at startup a few times. One of the times, it threw P0300, P0301 and P0302 so I read up what I could find, replaced the EGR cooler, cleaned the elbow, cleaned the intake & replaced the spark plugs & replaced the instake manifold gasket. Coolant was down 1/2" on the tank, have always taken it to the dealership for oil changes and they did not note the loss in the past.

    All was good for 11k. At 162k, the problem came back a couple mornings, so I added the head gasket fix (I know, bad idea, but the leak was very slow, and I only added 4oz). The coolant was down 1/4-1/2" in 11k, the shake was only at a cold startup (no CEL or other codes present). That worked to 171k, where we are now. She had a few issues, even shook one day - taking off from stop lights after being warm. I knew it was either fix it or replace the car. The car is a great car in nice shape, so I want to fix her. I had the head checked for flatness by a local machine shop and they cleaned it. I installed the felpro head gasket, new exhaust manifold gasket along with a new timing chain and new felpro head bolts. I RTV'd the timing cover and the cam hold down cover, setting the cam cover to proper torque spec. I added the valve cover back on with the new valve cover gasket. I filled both fluids (Oil and coolant). After connecting all of the plugs (except the harness for the windshield wiper motor), I attempted to start the car, it sounded like it was running for 5 seconds (a little rough, but not the violent shake) and then shuts down, Providing code P0340 - Cam Position Sensor. I cleared the code and started it gain, same issue. I unplugged the connector, visually inspected the wiring and the sensor and nothing was damaged or cracked. I then found the 12v battery to be low so I put it on the charger overnight (It was fully charged in the morning). I double checked the timing yesterday morning and it was still spot on. I ordered a Cam Position Sensor, got that yesterday and installed that last night, only to have the same result and same code - Runs for 3-5 seconds and then shuts down with the error code, red steering wheel, etc. Help!
     
  2. ZX Nutt

    ZX Nutt New Member

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    Screenshot_20210327-192507_Torque.jpg I followed the instructions that I found. I pulled the HV battery disconnect, reseated the 2 main connectors under the hood and the 4 behind the glovebox. I pulled and cleaned the crank sensor and the camshaft sensor (neither were very dirty). I am still getting the same code.
     
  3. Mendel Leisk

    Mendel Leisk Sand Pounder

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    First thought is timing chain off, but you’ve done 11k since head gasket replacement. Stumped.
     
  4. ZX Nutt

    ZX Nutt New Member

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    20210323_080142.jpg 20210323_075943.jpg
    Head gasket was just replaced, but I rechecked the timing.
     
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  5. howard chang

    howard chang New Member

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    Hey ZXNutt, did you ever figure this out? I just replaced my HG, water pump, and thermostat this weekend. Tried starting it and I got p0340 as well. same problems as you. Tried resetting hybrid battery, starter battery, pulled plugs for 10 min. Still notBeen stumped for a couple days now.
     
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  6. Tim Jones

    Tim Jones Senior Member

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    Bummer............. I recommend selling theses cars at 150,000 miles
     
    #6 Tim Jones, Apr 16, 2021
    Last edited: Apr 16, 2021
  7. ZX Nutt

    ZX Nutt New Member

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    I have not figured it out yet. I recharged the hybrid battery and have just gone back to recheck the timing again. Looks perfect. Exhaust lobe is on the rectangle (the E and dot are at the 3 o'clock position), the intake lobe is aligned at the line with the dot on the front face. Flywheel is at 0. I replaced the cam position sensor with a new one direct from Toyota, no change, same code. Did you figure anything out?
     
  8. Samuel Williams Jr

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    A possible viable explanation could be the timing is 180 degrees out? TDC on the compression stroke and TDC on the exhaust stoke, would both have the timing marks in the correct position but only one is right.

    Number one and number three would both be at TDC and the timing marks align. But it has to be on the compression stork not the exhaust (I believe, it's been awhile.)

    The cam lobes would be on the flat (valve closed) you could put a finger on the spark plug hole and rotate the motor, (have a friend turn the crank) when you feel compression, you would know your on the compression stoke. And that would be the true TDC.
     
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  9. rjparker

    rjparker Senior Member

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    You need an auto diagnostician that can check the timing with a scope. Since the problem happened immediately after the head gasket, I would guess a wiring problem or a timing mistake that happened during the reassembly.

    It certainly was not the first cam position sensor. We had one guy who installed a new chain tensioner that caused a timing problem. It was not the right part. I have heard of people using the wrong timing mark.
     
    #9 rjparker, Jun 13, 2021
    Last edited: Jun 13, 2021
  10. ChapmanF

    ChapmanF Senior Member

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    When I was a younger fella, I had a knack for putting distributors back in that way every time, and wondering why the engine didn't start. (Well, after the first couple times I didn't wonder anymore, just said "guess I did the distributor thing again" and put it back in the right way.)

    But that was on engines that (a) had a distributor, and (b) had it driven separately by a gear on the crankshaft or oil pump. so even though the valve train and distributor both go at ½ crankshaft rpm, it was possible to have them not match each other in phase.

    On a Prius engine, there is no distributor. The valve train is the only thing in the engine that goes ½ crank rpm, so there isn't anything else to be out of phase with it, and the spark timing comes directly from a rotation sensor on the camshaft, so as long as the sensor works the timing can't be off.

    When you're putting the timing chain back on the engine, and the cam and crank marks are lined up, that's when you establish the timing relationship. If the marks are where they belong, it's right. If you're still thinking "but what about the compression vs. exhaust?", picture this scene: you're about to put the chain on, the cams are at the proper cyl 1 valves-closed position, the crank mark points at zero, and suddenly you think "wait, I'm out of phase!" and spin the crank around one full turn till it points at zero again, before you put the chain on. As the chain isn't on yet, that move only puts you exactly back where you started. :)
     
  11. Samuel Williams Jr

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    LOL V8 and a distributor? Most likely no one under 50? Has no idea?

    But I do. And in as much as I will be getting back into this crap again with my to be reborn, Turbo 92 Tercel with, Big Power! Talking 300 hp plus up from 78 hp stock. It has been awhile.

    But my question is, if all timing marks are lined up. At TDC should all valves be closed at TDC? So the cams would be on the flats? Both valves closed.
     
  12. ChapmanF

    ChapmanF Senior Member

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    On a Prius inline 4, when the crankshaft is pointed at the TDC mark, both pistons 1 and 4 will be at TDC.

    If you have aligned the cam timing marks with the colored chain links, the valves for cyl 1 will be closed, and not for cyl 4.
     
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  13. mannypan

    mannypan Junior Member

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    Ok let's put this to an end.. just looking at your top timing marks means nothing . Just because you crank mark says top dead center means nothing.. take the balancer off. Look with a flashlight you will see a dot then look an make sure the colored link is centered.. more than likely it will be 1 tooth higher than the dot... only 2 reasons that will happen..1 they were not set properly during instalation.. or 2. Most commonly done. Is not releasing the tensioner PRIOR to starting the engine.. I do this for a living and have done Well over 100. You have to see all 3 marks.. not 2 and assume the bottom is right.. if you need help let me know..
     
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  14. ZX Nutt

    ZX Nutt New Member

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    For anyone following, I took it apart again last weekend hoping to find something major. I checked the new timing chain marks against the original timing chain, they were on the same links The timing was perfect like I thought. So I started putting everything back together. When I was about to put the valve cover back on, I looked at the underside of the cover to find a tiny glob of sealant in the oil passage that feeds the oil to the rest of the valve train. How it got there, I have no idea. I cleaned that out, then blew through those passages with compressed air to make sure there weren't any more blockages. Guess what...she lives! Started right up, no weird sounds, no error code! It ran for about 5 minutes, charged the hybrid battery and after it stopped from needing to run, I hit the gas pedal, it started right up ran and shut down like it should. It was simply missing lubrication! I do have a leak now at the timing chain tensioner, but I'll replace that this week and be golden!
     
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  15. Gasketblower

    Gasketblower Junior Member

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    Hey I just did my Head gasket on my 2012 Prius V and put everything back together, OIL and Coolant topped off, I double and tripple checked my timing by cranking it by hand to make sure nothing was binding I turned the car on it ran for a good 5-6 secs nicely then it made winding sound and I started to hear metal on metal noises so I shut it off right away not sure what the problem was so I took off the valve cover and started to turn the engine by hand the Timing marks had moved when I would be at TDC the marks on the chain were not even close to where they was spouse to be, I checked my tensioner it had engaged just right and it was new tensioner as well the teeths on my sprocket are nice and sharp and the chain seem fine I do get abit of slack in between strokes but I think that's normal any kinda feed back would be appreciated I did get engine codes but none related to cam shaft position it was cause I Had forgotten to install the ground cables but I did that and it made the same clunking metal on metal noise, I am going to perform a compression test tomorrow using techstream software and compression kit but if anyone here has any idea what I did wrong please let me know, my timing marks moved and never lined up to where I put them initially after I cranked it by hand to Engage the Tensioner even went counter clockwise because that is supposedly thats how to engage the tensioner
     
  16. Gasketblower

    Gasketblower Junior Member

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    if the tensioner does not get released prior to starting engine does it cause damage to engine ? and put your timing off ?
     
  17. mannypan

    mannypan Junior Member

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    It can jump 1 tooth if not released. Hence the cam position code.. set the marks on the chain.. put timing cover on. Compress chain tensioner. Install.. turn crank CLOCKWISE. YOU WILL HEAR THE TENSIOR RELEASE. You'll hear it click a few times. crank it around at least 1 round.. and your good.. don't turn it backwards. The chain WILL jump.
     
  18. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Repair Manual is saying to rotate cranshaft counterclockwise (opposite of usual direction) slightly, to release tensioner, if I'm not mistaken:

    upload_2021-8-4_11-56-2.png

    And I believe this can/should be done before timing chain cover is reinstalled.
     

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    #18 Mendel Leisk, Aug 4, 2021
    Last edited: Aug 4, 2021
  19. mannypan

    mannypan Junior Member

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    Oh boy a keyboard mechanic.... I'm going to be blunt.. how can you set the tensioner with the timing chain cover off.. thats what it bolts to.. stop trying to give advice to something you have no clue of..I'm done with all the people on here that obviously are clueless on fixing a prius.. ill start calling you out.. and by the way someone might take you ill advice and screw up their car...
     
  20. mannypan

    mannypan Junior Member

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    And look at the diagram it says turn crank clockwise.. learn to read.
     
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