I would guess it's idle timing trim trying to keep the idle smooth. A sloppy timing chain shouldn't effect the timing on a Buick since they have a crank trigger. When a timing chain is about to let go or a cam sensor gear is wearing out you will see the cam sync moving around.timing bouncing around at idle sounds like a sloppy timing chain .
Yes thank you but again why not 0 deg ?Yes. The reluctor is set at ten degrees on a stock balancer. BHJ is usually around six
The factory timing is set that way because of the stock ignition control strategy. During engine cranking, before the ECM takes over timing, the 10 degree signal edge is used for timing.Yes thank you but again why not 0 deg ?
I will be using a BHJ soon with factory ECM and extender chip. Should I use it as is or ? And why they chose 6 instead of 10 deg ?
Answers are much appreciated.
Ok so at cranking it's 10 or 6 but once computer takes over it still using that reference and adjust timing in addition to that. So if trigger wheel is wrong then all the timing is wrong or off by that amount. That's why in aftermarket stuff you guys change the reference angle. But I have a Gen 2 and Extender Chip. Any way to adjust that ?The factory timing is set that way because of the stock ignition control strategy. During engine cranking, before the ECM takes over timing, the 10 degree signal edge is used for timing.
I believe you can order BHJ's set to stock timing.
You better verify this with a timing light once the engine is running.Well looks like BHJ must have corrected their fixture. Timing comes right about 10 deg. Did it very slowly in both directions since only thing in the block is the crank and one piston with no rings.
One other point of interest that threw me for a loop is that you have to put the negative lead of the volt meter to signal lead to see the voltage drop.
Thanks to all that replied.