Hey there. I recently did a head gasket replacement on my 08 L61. I figured while I had everything apart I would put in a new water pump and replace all the timing components and chain. I got everything back together and got an error code - p0016, "Crankshaft Position Camshaft Position Correlation Bank 1 Sensor A." I checked all the ground wires and harnesses (picking up an ohm meter tonight), cleaned the cam position sensor and crank position sensor and everything seems right, so my thinking is that I screwed up on the timing.

The question: while I have the engine apart, could I put all the sensors back in place, leave the fuse disconnected for the fuel pump, and restore power to check for the code again? I'd prefer not to keep purchasing new cam and crank bolts if I screw up again.

 

What resource are you using to time it? There's a couple PDF's out there and some how-to's on here that are pretty straight-forward.

Also, you don't need to replace those bolts if you haven't heat cycled them. Part of the TTY process is heat cycling.

 

Thanks for the info! I had it in my head that when they were torqued to spec, they were no longer reusable. I followed the Haynes manual. Started with cylinder 1 at TDC, then matched the colored chain links to their respective sprocket marks.

I'll follow another person's instruction on the process. The question still stands though: before I put the engine back together, if I put the cam and crank positioning sensors back in, could I assume that the absence of the p0016 code indicates that the timing is correct?

 

That seems to be the common thought process in the car community, but the reality is that when you torque them, they are still in their elastic zone and will return to approximately the same size after being removed. The heat cycle combined with the thermal expansion of the parts that they're joining is typically what causes them to be "stretched" to/beyond their yield point.

They've become so popular in the last couple decades because of how much aluminum is being used in engines now. Aluminum being much more affected by thermal expansion - this is why head bolts are the TTY bolts that you should absolutely never re-use.

Things like rod bolts, cam bolts, and crank bolts aren't subjected to as much stretch from thermal expansion, so I've seen people reuse them with good success.

 

Thanks for dropping that bit of knowledge. I'll put it back together this evening and see if I can't answer my own question about the sensors.

 

That's only true if the coefficients of thermal expansion are different. So steel bolts to aluminum parts, yes, the aluminum would stretch the bolt more. Steel bolts on steel parts (as you mentioned) would see no stretch, and steel bolts on cast iron would see no stretch or possibly relaxation. So if you have a bolt with steel parts that is specified TTY then you've deformed it just by torquing it the first time. You'd probably be ok reusing purely because the plastic stretch isn't huge but it's not the conservative route.