Rebuilt 454 running rich??

[Newbie 88]

I have a 1998 Silverado 3500 crew cab, 454 and 4L80E tranny. I just had the motor and tranny rebuilt. If you stand at the rear of the truck while it is running you can smell how rich the exhaust is. Its REALLY rich smelling. The computer isn't throwing any codes though. Can I adjust this or is it just a computer thing? Also, does anyone know what this truck/motor/trany combo gas mileage should be?

[jumpingjack66]

Cant help you on the tune, exept maybe take it to a shop with emissions testing equipment and see if it is really rich. (after all it is a 454). And about gas milage? Forget about it!!!!!!!!!!

[Newbie 88]

Right after the rebuild I had the emissions checked by the DMV for license tabs. Tested fine, no problems. How about the Hypertech programmers? Are the any good. How much do they effect gas mileage?

[jumpingjack66]

I would expect on a 1998 to see improvments from a programmer, maybe slight milage improvments, and definatly a purformence upgrade. You would need to open up intake system with a k&n fipk, as well as opening up exaust to get full benifits from a computr. Hyperteck is not neccesarily the best choice if money is know object, others will allow you to do more. do a search in threads about other brands...JJ

[Newbie 88]

My truck has a Banks exhaust system on it(3" dual exhaust with headers) and a K&N air filter already.

[jumpingjack66]

well your all set then. i have seen threads in this forum talking about different levels of programmers all the way up to software level that requires a laptop to use. Just depends on how far you want to go and how much you wanyt to spend. As far as yyour exaust smelling rich i would just have to chock that up to the massive bores your 454 has and i cant say i have ever smelled a big block like that that didnt have that rich smell. If dmv passes it its good for me...JJ