I have gotten what I thought was a good tune down. I have a 305 TPI run with a 730 ecm. The car can cruise around fine and do light accel in closed loop or open loop. When I try to do any closed loop medium to hard accel it will bog horribly and gain little speed. It is the same with or with out PE enabled. The catcher is that it will pull great in open loop. The O2 voltage is never higher than .6 in open loop. I have not actually floored it or gatten above 80 Kpa though.

I have watched the BLMs. During the light accel in closed loop they are dead on. When I go for the medium accel though they usually range in the 128-120 range. They are varying. The O2 voltage never drops below .45 volts, so it is not overly lean. I can post tables and such, but was wondering if anyone could give me some direction to go first.

 

If your 02 sees .65 as a high and a low as .450 something is wrong right there :-)

If you are not making it clear if it varies, you might be in need of a reworking of the timing table, aka dropping it out faster and/or could be issues with AE.

I would find out what is up with the 02 stiff first personally.

It should swing both above and below .450 when in closed loop.

later
Jeremy

 

An O2 that never drops below .45 is constantly leaning the mixture. That makes the engine run super lean and gives you the problem you mention. When you mash the pedal to get open loop you are adding fuel and losing the O2 reading.

 

probably an oil or carbon or antifreeze coated O2 sensor, or it's just old. Time for a new one probably.

 

While in closed loop it will stay steady at .400-.500. It will stay there for cruise idle and light accel. When I go to med-hard accel I will get the problem. I get the problem with or without PE I have raised the AE. I started out with the 92Z28T5stockbin from moates.net downloads. Do the stock cars stay at .450 volts when accelerating? Not in PE though. What are you meaning by spark not leaving fast enough?

 

The O2 sensor can go below .450 volts, I have seen it. I have hooker long tubes on this and it is usually OK.