Well, I took the Vette out for a spirited drive and I decided to do a little run. Well, the car was throwing black smoke out for 2-3rd gear to redline, approximately 6200 rpm today.
Well, the last time I saw this much smoke was during a dyno day where I was running excessive black smoke and was down 25rwhp from the last dyno ran with this combo.
Before I dive into getting data, later today, let me say what I know was changed by me that I did have problems with. The heated O2 sensors. I , not the builder of the heated O2 sensor harnes, pulled a pin out of the right o2 harness and repaired it with a new pin within the connector as it did show a code of a low voltage to right O2 sensor. That code is gone.
I do have an exhaust leak on the right side, but it is after the O2 sensor. It is on the extended pipe that meets up to the Header, DRM headers, and is about 1-2 inches after the O2. Is that too close?
The exhaust flange has no leaks on either side.
The tune is PCMforless and worked great until I changed out the O2 for heated ones. SO I know its not the tune, which was made with ECM data from driving the car via TTS data.
The injectors are fine and dont leak, the pressure holds and is 43psi.
I am all ears guys, what do you think?

 

Did the engine warm up before you took the drive? do you have the ability to record data? Does it feel like it's running on all 8? That exhaust leak is probably close enough to the sensor to affect the reading. I'd get that fixed first. A datamaster recording would show it pretty quickly if you can get one.

Do you know if the heater circuits are working in the O2s? If not, turn the key on but don't start the engine. Let it sit for 5 minutes then see if the exterior of the O2 is warm. Pick you own method for that, I haven't touched one yet that was hot enough to burn. Just be sure your working with a cold engine. This is assuming that when you installed the heated O2s that you ran the hot side to an ignition switched power source.

You don't REALLY need the heater circuits working, the stock 93 O2s that are not heated simply depend on the exhaust to heat them up but take a little longer.

 

Okay, I tightened the exhaust leak, even though it was very small. The O2's are heating up, and I have a datamaster file I just went out and did. I havent reviewed it yet. Can you?

 

sure, send it over to w0442@mindspring.com

 

Looks like you might still be fighting an O2 sensor or an exhaust leak. The left side is showing some pretty low values I also noticed that your injectors are maxing out before you reach 6k rpm. I hope you don't plan on spraying yet....at least not with those. Not sure how long you've been running those injectors but if you've got one that's not working correctly, it could appear as an O2 problem since it throws the mixture off.

You say it ran fine until you switched to the heated O2s so that is likely the source of the new problem. When I switched to heated O2s I wanted to avoid any connection issues with the O2 sensors and soldered the connections. It's not really necessary for the heater circuit but the signal wire operates on a scale of millivolts and a bad connection can make a big difference on the reading.

 

I run 30# Ford Injectors and a GNX fuel pump from GM, so I know I am on the edge for thisi pump.
I wont be spraying this, and ew dont have a track anymore so racing isnt a concern. I have time to work on this fuel issue, which may be in need of a better fuel pump, to handle the HP of the 396.
The left side may have a problem, as when they put my exhaust back in after doing the tranny they put a bracket on the exhaust, that bolts to the corvette, on backwards and it pulled the collector out about an inche and a half. I will put a good clamp on it, and I am going to weld up some of the right exhaust stuff.
SO, you could see something wrong with the left? or both.