Why does my car only run good with a very rich fuel mixture?

[stangboy]

Well, here's the deal. My car seems to run better when its running rich. I don't have a rich/lean guage but I can smell how rich its running and it has absolutely TERRIBLE gas mileage. This past weekend I finally readjusted my rockers since I built the motor....BTW does it mean I set them too loose or too tight if i hear them a little more now then I did before?.....After redujusting them I brought my fp down to 36psi vacuum off it was at 40psi. I drove it for a whole day and it ran like $h!t so I brought my fp up to 38psi and its running better, but you can still smell how rich its running. Should I try bringing the fp down lower than 36psi or would that be asking for trouble? Some friends of mine told me that their cars run better with the fp set low like 30psi....I'm just scared to bring it down that low. I can't afford to burn up a piston due to a lean condition.

 

[GTJake]

Stock FP is around 39 psi. You're prolly moving alot more air now with those 185s and 1 3/4" headers. You probably just need a tune.

Jake

 

[chefster]

sounds like an o2 to me

 

[mo_dingo]

You really can't judge your a/f ratio by the smell of the exhaust.

Just get a dyno tune or a wideband O2 sensor w/ a/f ratio gauge. That is the only solution.
Scott

 

[stangboy]

Ok, who sells wideband O2 sensors and how much do they cost? I can't afford a dyno tune right now but I was gonna order a custom chip from JMS. I've heard nothing but good things about their custom chips.

 

[BlackVert]

another option is the TwEECer....you can tune it yourself if you are into that sort of thing...