Start rounding up some tools to begin. You'll need to loosen the distributor hold down bolt, which is 1/2" but 13mm works as well. It's not easy to get to, so you might have to use a u-joint with a socket or even borrow a distributor wrench with all the unique bends made in it for this application. Some of your larger auto parts stores might have these on a lend or rent basis.
Turning the engine to position it for the procedure is the next trick. While you could use a 1- 1/4" socket on the crankshaft bolt, I tend to use the alternator
nose bolt for this purpose. The big nut is 7/8" and the shaft will have a 10mm hex cut into it as well, so you could use either size. The nature of your serptentine belt tensioner is that it won't allow clockwise rotation without applying more pressure to the belt... it just slips when turning the alternator in this direction, so I use a 15mm wrench on the tensioner pulley bolt and a motorcycle tie-strap (the friction buckle type) on the wrench to pull the belt tighter which frees up a hand. By working from the top it saves you the up-n-down movements needed to lie on the floor... position the crank... and recheck your work over and over again.
Next, locate the scribe marks on your crankshaft balancer that will be used for engine positioning. You'll find heavy cuts that indicate TDC for all 8 cylinders every 90 degrees, but those aren't the ones we'll be using. We need the V8
marking, which is cut pretty close to one of those heavy marks... about 10 degrees to the left... and might be hard to see thanks to the "scalpel" the factory used to make them... these marks are pretty light and might be hard to find. Another mark that will look similar (V6) is also on the balancer, so be careful to avoid using that one.
Rotate the engine until you align the V8
mark with the stationary TDC mark on the timing cover, which will be at about the 2 o'clock position as you stand in front of the truck. If you happen to go past the TDC mark or just want to try again, back the crankshaft up at least 20 degrees and do it again. This keeps all slack from engine timing mechanisms on the trailing sides of the gears and such, just as if the engine was running.
Now positioned, get the digital voltmeter turned on and be careful to not hit the starter as the key is turned to the ON position. Set your meter to 20 volts DC and connect the black test lead to battery
negative or some good ground source. Touch the red lead to battery positive to verify a good ground connection.
You need to backprobe the tan/ yellow
wire on the distributor pickup (cam sensor) wire, best done at the harness side connector... the one with the rubber weatherpack sealing at the wire end of the unit. Insert a paper clip into the connector until you see voltage shown on the meter, which could be 5v or something very close to 0v... which is the matrix this sensor operates with. Disconnecting the cam sensor right there momentarily to be sure that you have a good 5v signal and then reconnecting it may be necessary, since you'll either be on one side or the other of the 0-5v square wave it generates and might not be able to tell if you have a good connection at the lower value.
Once you're sure that you have a good connection to the signal wire, reconnect it and we'll move on to the actual adjustment.
Loosen the distributor enough that it can be turned easily by hand and then turn it clockwise
as far as it will allow with the hold-down still in place.
Now turn the distributor counter-clockwise
until you see a transition in the cam sensor output voltage. It can go from 5v to 0v or the other way around, but what you're looking for is the transition point, which is where you stop and lock the distributor down. Done!
Just like at the crank, I prefer that you back the distributor up a great deal and start over if you're not happy with the adjustment to get everything operating in its normal relationship. With the distributor shaft moving CW during engine run times, you need to turn the housing CCW to maintain that same effect with the engine stationary.
It's not rocket science and you have a full 10 degrees of offset that the PCM will accept in either direction, but you might as well set it as close to center as possible. Although the engine will still run at the limits of 10 degrees, crossfire can still happen with things being at the edges of the acceptable range. If nothing else, getting it as close to zero offset as possible extends the time between adjustments a bit!
So sorry to keep you waiting while JA sorts out its software issues. It was leaving me only about 15 seconds to bring your question up.... type a response... send... SPELL CHECK... and then send again. Not much room for content there! The original post for you was almost done, just getting cleaned up a bit and then this hit and scrambled the whole thing. I disconvered that I could use the EDIT function only within the last 20 minutes... which is what it took to clean the original post back up.
Keep in mind that the site is still messed up for me from this end, so getting back with you might be difficult... but I'll find a way!
Good luck and I'll see you in a bit!
Edited by Dodgerench on 3/13/2010 at 7:38 PM EST