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Camshafts timing and a trans swap

1K views 14 replies 5 participants last post by  Tomvw 
#1 ·
Hey guys, it's my first time posting here, even though I've had the pleasure to use this website for many times ever since the purchase of my 2003 Passat GLX 4mo 2.8.
Ill just get straight to the case in order to not waste anyone's time here. This is the first time I've encountered a problem with this car that wouldn't have discoverable solutions online, so thats why I am here. A long while ago my trans went out on me, I am a full time engineering student and have to work 40 hrs a week, which is the reason why its taken me MONTHS to swap out the trans. JUst recently I've finally finished putting everything together and tried starting her up. She cranked, I heard some combustions (I had to cut off the second half of the exhaust in order to pull it out so she was loud), but she never really started up, maybe if I kept cranking her a little more (i would stop after around 8-10 seconds) it would happen, but I am not as experienced in this area as much as I wish i was (in fact this is my first major repair), and i was just trying to make sure not to blow up my parents' garage. Anyhow, OBD gave me codes P0340 and P0341, for Camshaft position sensors on both banks. Of course my fear is that I somehow must have messed up the timing and bent some valves when trying to start her up but I still have hope. First of all because i do not have any clue how i could effect the timing, i did have to spin the flywheel in order to bolt on the torque converter, but in my understanding the cams should have spun correctly with the crank, since i haven't touched the timing belt. I did research and i believe that these engines are ok to be spun both clock and counter clockwise, but maybe that could cause issues?.. The connections for the sensors should be intact, even if i did mess it up, i doubt that i would have done it to both of them, and the sensors themselves were ok before tranny blew. Since she's already pretty much assembled Im trying to avoid getting her back in service position, because of lack of time, but based on what i could see from the top, the cams are lined up correctly (the big holes on pullys will face each other if i get it to TDC, which i didn't do even though now i realize i should have).
This is all that came to me from the top of my head about this so if any of you are willing to help and have some questions please let me know. Thanks y'all.
 
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#2 ·
Just theorizing here ... two possibilities come to mind
1. Rotating backwards created enough slack in the timing belt to give a temporary misalignment when you started it and triggered and stored a code, or
2. The main timing (belt) is OK, but there is an issue with the cam chains. To check this, you need to pull valve covers and verify the timing is Ok on all 4 cams

Given that the car sat a long time, it's hard to say if you have a definitive non-start problem or not. Bad gas creates bad running. Just me, but I would probably reset the codes to see if they recur, and if they do then check the cam chains. My logic is that if any damage happened, it's done already.
 
#3 ·
You should not turn the engine backwards (counter-clockwise), one of the reasons is that
the oil pump runs backwards and sucks the oil out of the system, collapsing the Cam Chain Tensioners etc.


I think it would be wise to first check the timing on all 4 cams, both Valve Covers will need to be removed.


These 2 codes are for the same sensor, I think Bank 1 US passenger side.
Check the sensor, wiring, and connector.

6725/P0341/000833 - Camshaft Position Sensor (G40): Implausible Signal
16724/P0340 - Camshaft Position Sensor (G40): Malfunction

Clear the codes, if they come back you could try swapping the 2 sensors and see if the code follows.


Check and post compression on all cylinders.
 
#5 ·
Sorry for taking so long, finally got to take off the valve cover, i believe the chain looks like its in correct timing, took the pic of it just in case im wrong. Is that the correct way of checking the timing or is there something else i need to do besides counting the amount of links?
Also thanks for pointing that out, Tomvw, I typed those codes in from memory, it should have been P0341 and P0346. So the sensors on both sides. I dont have the tools to check the compression, would it be worth it to buy them in order to find this out? so would the rotation counter clockwise cause wrong timing on both banks?
 
#7 ·
Questions:
Did you work on the cylinder heads? Were the cam sensors removed?
If you removed the sensors, take them off and make sure you install the reluctor wheels correctly, they are keyed onto the camshaft's end. You should notice two little notches/channels carved onto the camshaft. The reluctor wheel has a little cutout tab that fit into the larger channel. You can eve bend it a tiny bit to make sure it is seated on the channel. The fact that the sensors worked b4 u started the swap is irrelevant. there's a good chance you fried'em if the reluctor wheels were reinstalled incorrectly.
 
#11 ·
I can't see anything wrong in your pic, but can't tell if it is right.

Check the wiring and connectors to both Camshaft Position Sensors.
Check the wiring and connectors to both CCT solenoid valves.
Check the wiring and connector to the Crankshaft Position Sensor.



??????????????
 
#12 ·
You replaced the tranny, ok. Did you mount the crank sensor back into the new tranny bell housing before buttoning the car? The Ck Pos. Sensor works in conjunction w/ Cam Pos. Sensors, so if you don't have it connected you could get those cam sensors codes and you can crank the car ad calendas Graecas and you'll never be ale to start it.
Other then that, you should follow Tom's recommendations
 
#15 ·
You incorrectly suggested that I hadn't mentioned something that I did say; I didn't sat anything about you.
"Other then that, you should follow Tom's recommendations"

A person would have to be pretty stupid to not notice that a sensor was not mounted while they were checking its wiring and connector.
 
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