so my truck has finally finished its tear down and rebuild of the engine. i have done quite a bit . upgraded the ignition system. coil, wires, cap, rotor. installed a new cam. installed new K&N filter. put in some flowtech long tube headers. only hard thing about that was getting the starter back in. but i got it in without having any problems. and after that is an H pipe to flowmaster 44 mufflers. only thing is that i still havent put the oxygen sensor back in the collector yet. and when i took the original Y pipe off. i had to cut a pipe going to the back on the intake or something and im assuming that effects emissions? i ran it today and it ran okay.. but not how i thought i would. any suggestions on why this may be?

 

You may need to get your computer reflashed to compensate for the upgrades. SD motors aren't friendly to a lot of upgrades with stock computer settings

 

You really need to install that O2 sensor very soon. The PCM relies on it to adjust the fuel/air ratio in closed loop operation. The small tubing you cut is for the AIR system to supply air to the converter(s). You will need to cap that tube or better yet remove the TAB/TAD valves and also plug the ports on the back of the heads. Leave the TAB/TAD solenoids electrically connected to keep the Check Engine Light from coming on.

If you used a Speed Density friendly cam you most likely will not need to get a custom tune. There is no "flashing" per se on this vintage truck. It requires a tuner or a chip on the J3 port of the PCM.

 

x2 I couldn't think of the term at the time so I just threw something out there

 

yea i guess speed density plays a part in this then. i was planning on getting a hypertech chip.. would this maybe help it run better?

 

No, that will not help. All those off the shelf chips do is bump the timing and cost you money. A custom chip may be in your future.

 

damn.. i was hoping to get off the hook easy.

 

What are the cam specs. If its not within a certain range the SD will never fully accept it

 

its the comp cams cam and lifter kit 31-255-5.

 

That cam is fairly tame. Have you capped off that AIR tube pipe yet or better yet removed it then plugged the back of the heads? What about the O2 sensor, is it installed yet? Verify correct plug wiring order, also make sure you have the wires separated. Cross-fire is a well known issue.

 

well i havent capped off anything. but i have installed the O2 sensor. and ill admit it does seem to drive a little bit better after that