matt.bailey

I recently changed an engine in my 86 RX7. It ran fine before the replacement (due to overheating) and the new (used) engine runs perfectly. Problem is that the Tach reads half what it should. Secondary injectors kick in at 1700 rpm instead of 3500. At an idle it shows very low (300). It also has a low idle problem. It will stall out until it is fully warm and then it stays running although the idle remains low. It seems like two seperate problems but I wonder if the tach issue was corrected, that the low idle would fix itself. BAC valve and AIR valve remain possibilities but I feel that first the inaccurate RPM should be addressed. Thanks for any help
Matt