Camshaft Position Sensor Warning

fatalbert · Post by **fatalbert** » 09 Nov 2016, 12:38

I just finished replacing the head gasket on a 1993 Volvo 850. I was extremely careful in all the process steps and took photos along the way as a reminder of how everything goes back together. After completion and trying to start the car, it did not sound right and when it did start, it ran poorly and misfired.

I checked all connections, timing and vaccum lines over and over. To make a long story shorter, and after thinking on it for several days, I figured out it is possible to put both the distibutor and cam shaft sensor plate back on 180 degrees off. I checked the distributor first and it was OK. I finally pulled the cam shaft sensor and plate behind it off and turned it (the plate) 180 degrees. Now it starts and runs like a top. I have not seen this word of caution about the sensor plate anywhere.

Sorryfor the long post, but I did't want anyone else to pull there hair out over the same mistake I made. Hope this saves someone else in the future from this frustration.
Thanks, Al

Post by **rspi** » 09 Nov 2016, 19:28

It really only fits one way, the piece is offset a little. I guess it can be forced on 180 degrees off. It's good to note the orientation of things when removing them.

Glad you found your issue.

fatalbert · Post by **fatalbert** » 19 Nov 2016, 17:26

The 1993, it can go either way. It was not necessary to force it or I would have taken notice. I'm not a complete idiot, maybe only half of one. I rotated the crank shaft a couple of revoutions to make sure everything lined up as recommended, then realized I had not noted the position of the sensor or the distributor before doing so. It is posible to install both the dist. and cam sensor 180 degrees off. I guess if I had a later model 850 it is not possible to install incorrectly. As an engineer, I find it troubling that an engineer designed something that can be installed backward.