Ok here is my problem, I have a 91 Firebird Formula that I finally got running and took it for a drive and noticed it seemed low in power and it feels like it is surging. I do have some codes that I need to work out first, code 24 (got this fixed replaced vss sensor) code 33, code 43, code 51 (got this when I accidently tried to start it without a prom installed). Problem is I do not know what code 33 and 43 mean for speed denisity. I did some datalogging and found that the computer is retarding the timing up to 16 degrees for knock, but the knock cuonts are at 0. The knock sensor is for a 88 firebird with 350 tpi, would I need to switch it out?? i also tried to back thee timing down a few degrees but that did nothing. Any ideas??

 

code 33 Manifold Absolute Pressure (MAP) Sensor Circuit
signal voltage high - low vacuum

code 43 Electronic Spark Control Circuit Meaning the ECM is getting a knock signal from the knock sensor.

 

Ok took it out for another test drive today and I was able to roll the windows down and all I heard was almost constant pinging. The engine is all stock except hyperutectic (sp) pistions that bump the cr to 10.5:1. I am running 92 oct fuel and thinking of puting in 5 gal of 110. My trans am has 10.7:1 forged pistions and i can run 92 oct all day long with no problems. Any other ideas?? Also TPeye thanks for the code descriptions.

 

mine was pinging and it was due to the timing being like 34 degrees, backed it down to i think about 10 or so and that stopped right away

 

I did forgot to mention that the dist timing is at 4 degrees and still pings very badly, mainly at 1/2 throttle or so