New head gasket, now P0340

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

 

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.

 

Bummer............. I recommend selling theses cars at 150,000 miles

 

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.

 

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.

 

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.

 

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.

 

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.

 

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..

 

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

 

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

 

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.

 

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



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

 

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...

 

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