I hooked a timing light to my truck today to see where it was running at. Let me start by saying if you're going to loosen your distributor hold down bolt, be careful not to break the oil pressure sending unit next to it (ask me why I say this).

The Haynes manual I have doesn't say anything about disconnecting the temp sensor before doing this, just says to get the engine up to normal operating temp, which I did. With it connected, I noticed that the timing was bouncing all over the place, staying close to 10* BTDC but occasionally going higher than the stamp reads, and as little as 4-5* BTDC. All this while idling at 700 rpm. So at this point I'm thinking I must have major slop in my timing chain, distributor gear, or somewhere, but for grins I disconnected the temp sender.

After about 5 seconds, the rpm went up to ~750 and the engine got smooth as silk, I mean, it didn't shake vibrate at all, and I thought it ran pretty smooth to begin with. And the timing mark pretty much glued itself to 12*. I don't have the check engine light on, but is there a possibility that the sending unit could be bad, or dying? Also, does anyone know if there's a special socket needed, or atleast a specific size, to remove the oil pressure sender?

Thanks!

 

Is your distributor shaft loose...excessively? The pickup plate loose on the shaft? Yeah disconnecting the CTS is the way you set base timing back then. They used to put the instructions on the label under the hood but i'm guessing it's gone by now...?

 

I still have all the labels under the hood, but they only say where the timing is supposed to be, not how to check it or get it there. I checked on here several times and many mentioned disconnecting the sensor. That's why I checked it both ways. I never actually loosened the distributor, gave up when I broke the oil pressure sender but I had the light hooked up so I checked it anyway. Just seemed odd how disconnecting the sensor took all the bounce out of it and settled the mark right at 12*.

 

The ECM stops advancing/retarding timing when you unplug the CTS. That bounce you're seeing is the ECM doing it's thing.

 

this may soud odd,but i used a faucet basin wrench to tighten my oil sensor when i put it in. i did not have the socket for the longer version sensor.
i do not know where the socket for the longer sensors is available from.
there is a special socket for them they come in 2 sizes,i think its 1inch,and 1 1/16 th. CRAFTSMAN #947695. this socket is for both sizes,but is only for the short version sensors. good luck