First off......Let me apoligize for this post being so long. I am just trying to give everyone as much info as possible as to what the situation is. Please take a moment and read this and give me some insight....

I have posted this in the LT1 Tech section with not much luck for advice........

My problem is this :

I removed the Y-pipe and immediately loaded the car on the trailer and took it to the track......

It ran fine in the staging lane and launched good (broke loose but still ran 116+ mph)

When coming back on the return lane, the engine seemed to be running real rough. I could rev it up high and it would rev perfectly. It just seemed to be sputtering some at lower rpms and blowing some black smoke while slowly returning to the truck.

I waited an hour or so and pulled around to the stagng lanes again... This time the lanes were backed up and I waited about 15 minutes to get on the track. Most of this time was spent with the motor cranked and idling. It was smoking (black) worse and worse and the raw fuel smell became nearly overwhelming. It ran very rough, but would clean up if I revved it up. I got on the track but it had began to miss, so I slowly went down the track and loaded the car up and came home.

I waited till the weekend and went to pull it in the garage and it wouldn't even crank. I decided that since the oxygen sensors are within 2" of the collector flanges, that the oxygen sensors were giving false signals with the y-pipe removed....So I put the y-pipe back on and changed the plugs right there in the driveway.
The plugs were COATED with carbon (very black and full of carbon build up).

The car cranked perfectly then and idled and revved perfectly, but was obviously still running very rich (black smoke and raw fuel smell and fuel spray throug exhaust).

I checked the fuel pressure and it is at 47lbs. with the vacuum removed from the FPR. I also found that when I rev it high with the vacuum line off, that the fuel pressure drops to 28 - 30lbs. This is definitely a problem....I know..... Could this be caused from the overly rich condition due to the injectors flowing so much excess fuel? I changed the fuel filter with no change.

The car will rev fine in the garage, so I decided to take it down the road. As soon as i pulled onto the road, I punched it and it sputtered and feel flat(nearly died)....Slip it in neutral or park and it will rev to 6k fine.......Of course it still blows black smoke but it will rev up fine......

I have drummed up someone that has a cable to hook to my OBD2 port and scan with Freescan or Datamaster this evening.

My question is this.... There are no codes..... What sensors or parameters should I be looking at when scanning and what "values" should be normal for those particular sensors?

Any ideas or suggestions are appreciated....

A detailed list of mods on the car can be found at :

http://www.fbody.com/members/396CamaroSS/

 

You might try just disconnecting the battery for a few minutes and see if just the pcm needs to be zeroed out (your stunt really altered the block learns). Next step would be to clean the 02 sensor (wire brush, blow torch).

Oh, and biggest things to look at are BLM and integers (both should be around 128) and 02 readings (under 1000 or 1.0 depending on how it reads). What scan program you using?

Hal

 

I couldn't see anything that looked out of wack while scanning axcept 02 numbers dropping into 150 range when revving over 3800 rpm....Fuel pressure was also dropping about 20lbs at the same general rpm range........ Problem Found!!! NOS Inline Fuel Pump was the problem!!! Removed it completely and fuel pressure is remaining constant througout rpm range and car is running great..........

 

I consider my fuel pressure guage in my car the biggest warning indicator I have. Its the most obvious dial to read because it would be a big problem to be lossing pressure under boost.

Hal

 

When I had my Y pipe off I had a similiar problem--ran good at first then got rich and almost fouled the plugs. In my case, the O2's were too close to the open air without the Y-pipe, they were seeing the open air as too much oxygen, so they basically told the PCM to add more fuel...not a good thing...I didnt read all of ur post, but that might be the problem. The PCM adjusts slowly to changes, i think just letting it run may help, and cleaning off the O2 sensors.