Just recently got my car back together and running. Mods are basic bolt ons and cam the the associated valvetrain. When the car is running it reminds me of the smell of a lawn mower, not to mention it seems to smoke a bit. It's not fully tuned yet, didn't know if its just running rich or if I have a bad valve seal (even though they're brand new) or something along those lines. Any help? BTW, pretty sure this is the section this belongs in, if not I apologize.

 

You will have a smell untill you get a proper tune. Improper fuel map is to blame for it. With most cam jobs you have to take out fuel in the lower RPM's. Sometimes as much as 20 to 30 percent has to come out. Most people think you have to add fuel to these cams. This is completley wrong. These cams do not work as effeciently at idle and for this reason a good percentage of fuel has to removed from the low RPM's on the VE tables. Most people just throw a cam in and let it ride. Without the tune you will not gain all the power you should be getting and not to mention just poor running characteristics and the smell. Hope this helps.

 

Are you running cats on the exhaust? If not, this could be the normal smell of the fumes that is usually contained by them.

 

Untuned it's going to run like crap, prob throw codes, and stink. If it's black smoke it's fuel. Get it tuned and try not to drive it until then. Even tuned with a big exhaust it'll stink a little. My cammed ls does. Tune is awesome and spot on.

 

Smoke isn't black. I've owned catless cars before and this didn't smell like them. The explanations you all provided make sense. It has a base tune on it at the moment but no idea how close it is to being right. I kid you not, fire up your lawn mower right now and that's what this car's exhaust smells like lol. Its not my dd so I'll leave it alone until I get to my tuner later next week.