I just put in my B20B in my 94 teg. I have AEM cam gears and and unorodox underdrive crank pully. The crank pully only has on mark on it. When lined up the timing belt crank spline with the oil pump mark, I put the crank pully on and it did not line up with the mark on the timing belt cover. I made sure the crank didn't move and then lined up and installed the timing belt. I cranked it over a few times and double checked everything. Once I fired the motor up it has a slight constant backfire not really loud but almost like a pop-ing sound. I adjusted my dist. al the way to the firewall and it helped. I am running open header with no cat or pipes. Is this my problem. It only pops at low RPMs at high revs it runs ok but not purfect. any one have any ideas?

 

Well, its never a good idea to run open header, because when it cools, it can damage the valves, thats another issue entirely though.

I would install atleast some form of exhaust manifold, and see if thay helps. Because if its that slight, it may go away once you have the whole system on.