Ok guys... here is a good one

1991 3.1L
new stock heads, gaskets, injectors,tune up, etc. Gas mileage is crappy so I go to check the timing asnd found:

1) there are 2 lines on my balancer that look like timing marks Anyone ever seen that?
2) Unplug connector and check timing. and cant seem to get either mark to line up with balance pointer, so I take out my snap on scanner and it shows 20 degrees with the plug disconnected. Idle is about 850. so I loosen the distributor clamp and cant seem to get timing under 17 no matter which way I move distributor..

ok so what gives?

I need to be at 10 degrees according to the GM manual, and im trying to get there to see if that cures my mileage issue.

any help is appreciated

 

I don't think you scanner will tell you the base timing. The engine is not equipped w/ a crank/cam sensor.
You need to figure out if your balancer is bad, like the inner & outer parts have slipped.
Remove #1 spark plug, turn the engine over by had till the piston is at the top of the stroke. If the balancer is good then the mark should line up w/ the zero mark on the timing tab.

 

You need to make sure your checking with the right groove on the balancer. It's the widest one on the balancer. It would help if you took some white out and painted the widest groove as it's much easier to see that way. Also make sure that your checking it with the #1 plug which is front passenger side. If it still doesn't line up then do what ex-x-fire said and pull the #1 plug, check the balancer with the #1 piston at the top on compression stroke. You'll know if it's on compression stroke because you'll be able to feel air coming out at the plug hole as you turn the engine by hand.

 

Ok got the timing back to 10 degrees BTDC, car runs but seems very sluggish.. With Headers, flowmaster muffler, no EGR and no smog equipment. I also did the Idle learn. Can i put a little more timing in it?

 

You can probably bump the timing another 2* without trouble