3.9 timing and sync question


New Member
rebuilding my first mustang motor and running into a small question. I can't seem to get my cam synchronizer set at 54*when at TDC. The closest I can get is right at 60*. if i go one tooth the other way its at about 40*. Will this matter if its at 60*. I am using the tool to set it by as well. Also, does anyone know what the hash marks on my Crankshaft pulley refer to. It starts with 3m3 then hash marks down to 313. TDC seems to be right in the middle of these marks. If i set my timing at the 3m3 mark, I can get the 54* on the synchronizer but the piston is a few degrees before TDC. Can anyone please offer a suggestion on this? I've read every post I can find on this, but none seem to have this particular issue. Thanks


New Member
I’m assuming the middle mark is TDC, can anyone confirm this.


Profile Violation
No, the middle one would be n-degrees before TDC. The line
above 313 is TDC, I believe, that's only for Piston#1 and timing
adjustment when doing the timing chain and so forth. The ECU
handles spark timing. There is no ignition timing adjustments
with coil packs.

If you want #1 TDC, pull the #1 spark plug and turn the crank till you see the
head of the piston on the compression stroke, turn and stop when it starts
to back down, then go backwards to center it. Or put a screw driver in
the hole, and stop it before it moves back down...


New Member
The engine is on a stand and I’m 100% sure #1 is at TDC because I haven’t turned the crank yet. When I put the balancer on that’s where it happened to line up. My biggest issue is the cam position synchronizer. The manual says to set at 54 degrees when #1 is at TDC. When I set it in place it’s either at 38 or 62 degrees.
If I’m using the correct install tool on the syncronizer locking it in place, does it really matter if it’s a few degrees off. The tab on the syncronizer will still be in the correct place within the syncronizer when #1 is at TDC. Does this sound logical?

6 Shooter

Well-Known Member
cam position sensor installation 2002 v6 mustang - Bing video

Based on the year model of Mustang, for 99-04 V-6 Mustangs, the best location is for the cam position sensor to be located at the 7:30 position, when installed. The factory sets them to the 4:30 position, but the connector and harness are very tight when plugged in. Moving to the 7:30 position will give some slack to the wire harness and avoid hitting the coolant return steel pipe.

It has been a while, but when the cam and crank are set in the correct locations, there will be a dot or mark on the crank timing gear and the cam timing gear. Those two marks must be facing each other, dot to dot. So, install the cam timing chain and release the tensioner. Rotate the crank 720 degrees and check the dot to dot marks to be sure they are touching or facing each other. If off, which is possible on first attempt, release the tension on the tensioner and move the chain one tooth and recheck by 720 degrees rotation of the crank.
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