Andrew760

This is a car I just bought for super cheap and I need to smog it to transfer the title. The smog for my zip is not on the dyno. I will first start by posting my numbers
CO2%
Idle 7.2 2500rpm 12.2
O2%
Idle 9.8 2500rpm 3.6
HC
Idle 168 2500rpm 70
CO%
Idle .24 2500rpm .12

Yes I do have a exhaust leak and I am 90% sure its at where the cat connects with the exhaust manifold. I am not sure if this could cause problems. The other thing to note was my timing was at 10 BTDC and it should be at 16 BTDC. I screwed with the timing the other day because it was running like crap in low rpm's and it ran much better when I turned the dizzy clockwise a little bit. I was using a timing light but it was hard to line up the lines and I did have the service connector jumpered. When I was turning dizzy clockwise was I retarding the timing? I also have a new O2 sensor on the car because it was throwing a code. The car also has a pretty new dizzy with plugs and wires.

Does anyone think fixing the timing will get the car to pass? Also which was should I be turning the dizzy to advanced it to 16 BTDC? Thanks for any other input I get.

Thanks

Former User

Fix the exhaust leak and set the ignition timing top spec using a timing gun.

Andrew760

Do you really think the exhaust leak could be causing a higher HC. That would not make much sense to me but I am no means a expert. It will be a pain to fix because one of the studs on the cat is broken and I don't think the studs come out. I could maybe use some exhaust tap to kinda repair it. Also I only need to get the HC down to 140.

Former User

The O2 sensor that plugs into the exhaust system is used by the ECU to determine proper air/fuel ratios. An exhaust leak increases O2 levels around the O2 sensor, making the ECU falsely believe the engine is running lean. The ECU responds by telling the injectors to pump more fuel into the cylinders, making the engine run rich.