hey all, i recently did a cam swap on my 93 trans am and now when i start it, besides needing a tune, it runs okay. However, when i drive it the car will miss a little. the opti was good when i pulled the motor. so that isnt the likely cause. BUT i drove the car with open headers to see how it would drive and it through trouble codes 13, 41 and 63. the 13 and 63 indicate an open circuit on the O2 sensors, any clue what would cause this? I had to cut the 02 sensor wire and add some length to it to reach the headers so could that cause it? or would running open headers cause the exhaust to not be hot enough to heat up the sensors (which are one wire). Finally, i would imagine that my miss is from code 43 (ignition control module open circuit) but wouldn't the car not even run if the icm had an open circuit?

any help is appreciated.

 

Well #1, you need a damn tune so don't expect it to run amazing.

#2, a '93 doesn't have heated 02 sensors so you need to run the '94+ LT1 02s and run a relayed, ignition sourced, power and ground to them to make them work. This is because with long tubes, the '93 sensor doesn't get hot enough to work properly, so heated sensors need to be added. Not to mention you are running open headers a few inches from the sensors.

 

^ What he said....how were you expecting it run in that condition? Get you're obvious issues fixed and then see what happens.

 

well i didnt expect it to run good, thats why the car is being tuned, but i dont think it will be very easy to tune a car that has a misfire or that the o2 sensors dont work on. i know i need a tune and ill get one but i expected to at least be able to drive out of the garage to park it in my driveway.

plus i have to drive the car somewhat to datalog it to see what i need to change in relations to the tune. i also think the code for the icm was cause by me unplugging the coil before the first start to prime the system with oil. but ill be converting to heated o2 sensors when i get the chance i have to install my wideband anyway

 

https://www.youtube.com/watch?v=II67...ature=youtu.be

i tinkered with the idle VE tables and got it to idle a little better. i still need to get my datalogger working because right now it was just a guessing game but it idles okay

 

Update: i know its a late one too lol.
installed heated o2 sensors and it didnt help, pulled the engine due to a blown headgasket. car had 5 broken pistons 4 of which were on the same side. Dont know why, or how they broke but they were broke. Heads milled, gasket replaced, and pistons replaced, put the engine back together and it runs fine, got a mail order tune and started tweeking some things on my own. car runs fine now. thanks for your help.

 

5 broken pistons?!?!?! Holy crap is that even possible, much less probable? Glad you found the problem(s) though.

 

I am going to be adding LT's to my 93 Z28. whats involved in the wiring portion of what you said here about the heated o2's?

" run a relayed, ignition sourced, power and ground to them"

 

Hey thats cool u got the fix. Its never too late for an update and feedback as it helps us all. I feel somewhat embarrassed u didnt get more help than u did and u still followed up the feedback.
BTW thats a lot of work in only 4 months so congrats u are probably a better mech than most of here.

Hope u have fun driving it now.

 

With a blown head-gasket and running it un-tuned for a bit I would bet detonation killed the pistons and the head-gasket.

 

Yeah, i couldn't believe it. The car missed from the day it pulled out of the garage though and i couldn't figure out why. the head gasket didn't blow until i raced it though but still i couldn't believe it had 5 broken pistons. She runs good now, minus it tearing out the trans. But i'm working on rebuilding it right now. Just have a 3-4 clutch pack problem trying to burn out.

Thanks for all the input though.

 

this is awesome

 

What part of Kentucky are you from?

 

Barbourville, It's about 30-40 miles from London.