OK, so I recently put an LT1 Cam, Vortec Heads, and a GM High performance intake on my 1991 TBI 305. When i finished the assembly I tried to start it, nothin. So then i played with the distributer a tad and it fired up, ran real rough. Finally got it timed I set it at about -6 BTDC. Took it for a spin and in ran like absolute crap. Backfired, hardly any power till about 4000 rpms, even then not much. I tried a few different times with the timing set at different places and it seemed to run best at -6 BTDC. I cant think of what is causing it to run like crap. I would really appreciate some input. Thanks. -Adam

 

Normally with a cam like that you'd want to advance the timing not retard it 6* and be sure to unplug the est wire when setting timing. You are in desperate need of a chip too.

 

Brons got it. You need to look into getting a custom prom. These cars will run slower with a stock RPOM and heads and cam work. You may have to advance the heck out of your car to get it to idle. What have you done to the vortecs? Are they milled or stock castings?

 

The chip is on the way, I wrote the guy at tbichips.com today. So it may just be the computer acting up because of the new cam? The Vortec's are stock, I just didnt have the money to do any work on them. Ill try the timing adjusment. thanks.

 

So it turns out im retarded, not my timing..No pun intended. I did have it advanced all along. I dont know why i said otherwise. So that gets rid of that idea.

 

sounds like what happened to me. all mods done at once cept tuning. i needed a lot more fuel. tuning was a necessity. no way around it. tried a vafpr and that helped but still too lean in cruise mode. vafpr helped WOT. drivability was terrible. welcome to world of eprom.

 

Brian does nice work. He did my chip. I'm satisfied for now. Put the timing at 6* and then increase fuel pressure and you're good to go.

 

Really Slow,

Are you able to download data? You will need a Winaldl cable to download some logs to send to Brian. Constant tweaking of the chip will be necessary to get it running right. That is the stage I am in right now. The other choice is to learn chip tuning yourself and dial it in over time.

 

I take it you have the valve lash set?

 

I second taking another look at the lash even if its probably ok. Fastest way is to set it with the engine warm and idleing. Are you also sure that there arnt any crossed up plug wires? Having the firing order wrong will cause an engine to run like crap as well. Although it wont be fast right off the bat and the tune will be a good deal off, the car should at least run and idle with an LT1 cam and heads.