Did a heads/cam install which also included an adjustable fuel pressure regulator. PCM was reprogrammed to meet my specifications by PCMforless. Set the fuel pressure at around 48'lbs. and it seemed to idle great but once I took it around the block the idle was rough and I had to rev it to keep it going....then...it started backfiring like an automatic machine gun and wouldn't stay running at all.....any suggestions? Would decreasing the pressure in the regulator (I think 43 lbs is stock) keep it from loading up...? What else could it be??

 

TTT

 

Did you put new lifters in? Did you let them soak in oil and pump them up before putting them in? If not then your rocker arms are too tight. Backfiring through exhaust is caused by valves opening too early which would be caused by rockers being tooo tight. If the lifters did not pump and you set the lash then after driving it around the block they pumped up and your lash would be too tight.

If you can, back them off all 1/4 of a turn and see if it runs better. If so don't just leave them at that, you need to reset them either while engine running or engine off. I think it's easiest with it running.

Please reply if this is the problem. Someone else just had this exact problem and never responded again to it, so I don't know if I was able to help them.

 

Crossed plug wires or RR's to tight.

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We didn't put new lifters in, I used the old ones. We pulled the plugs and they were all pretty much black. We put new ones in and stared it but it continued backfiring and after a couple of times it wouldn't even start anymore. We pulled a plug wire and now the engine isn't even getting fire. We put a brand new Optispark on the car while we had the engine apart so now I don't know....could it be the coil??

 

The timing gears may be off a tooth, crossed plug wires or misadjusted valves.

 

Did you ever figure out the problem?

 

http://web.camaross.com/forums/newre...threadid=85732

 

48 psi is a little on the high side and thats why your plugs are black. I would pull the O2s as well and clean. If this does not fix the problem then i would look at the RRs.