Hey guys my brother bought a 99 blazer for 450 of craigslist San Antonio with the motor in pieces in the back.while inspecting the block we found a bolt broken off in the cam cover and no machine shop would touch it so,this water head picks up a vortec 4.3 but he got the older 4.3 vortec that came in the 4x4s.so he tried to make the best of the situation and use the older short block and put the vortec heads and injection system on the older short block.anywho major money pit we get it together swapping everything new vortec heads,reluctor for crank sensor,t chain cover new crank sensor all that.put it in the truck and it won't run right the scanner says its got a cam crank sync problem.do you think the older cam isn't working right with the ECM and distributor or is there another issue here?hes ready to give up but would rather figure it out over 750 invested!maybe a custom tune??

 

Search for the CASE relearn procedure. Needs to be done on most GM's when swapping engines, ECU's, Etc. Also have you verified that the distributor was installed correctly? can be easy to end up 180 out and have no start condition... or 1 tooth off and it will run very poorly.

Edit: you said older shortblock with newer heads... what year is the block?

 

Like a 92 blazer with the intake that looks like mini ls1 not the tbi 4.3 the other one from the early 90s.it was maybe we should check that distributor again and ill check out That case relearn thanks for the help.

 

That would be the CPI