My car is running a little rich, especially at wot (black smoke on hard acceleration). Useing tunercat what is the best way to lean it out some? I am trying to learn some of the basics on how to tune with tunercat. Thanks

 

First you need to know what your Stoich is example in 98-02 cars it is 14.7:1 at idle and partial throttle(normal driving), then get some reputable tuning software such as HP tuner or LT1 edit or if its LS1 then LS1 edit, and a wideband sensor, then you can take it to dyno and adjust fuel trim at WOT. Thats what I would do but then again i have an LS1 and dont know a whole hell of alot about the LT1 anymore.

 

Stoichiometry is not relevant, and he has TunerCat, which is the software he needs for tuning his OBD-I 95. He needs to tweek the PE tables. But before making changes, try and find out WHY its running that rich. If you have long term fuel corrections adding excessive amounts of fuel in closed loop, it will do the same thing in PE mode. Check the long terms and verify your closed loop tune is satisfactory, before changing the PE tables to lean the power enrichment mode A/F ratio.

 

Do you have a log of the car so that we can see what your BLMs look like?

 

02 sensors??

 

Thanks guys, I will check my BLMs. If my BLMs are high the computer thinks it is running lean and then adds more fuel, is that correct? The car runs great I just hate the black smoke when I get on it hard. Thanks again

 

You are correct, if the BLM's are above 128 (or above 0%) the PCM is adding fuel to correct what it perceives as a "lean" condition. Problem is that when the PCM goes into PE mode (WOT) it uses the BLM's for the high load/high rpm cell to calcualte the fuel requirements, and it may run rich if the BLM's are artificially elevated for some reason.