TCS Trouble (Transmission Controlled Spark)
Working on my '70 4-speed car and having trouble getting the TCS system working. The system does seem well documented in the manual. The original M-21 was replaced with a '74 M-20 out of a Grand Prix. The '70 switch was bad so I purchased a replacement from an aftermarket parts supplier but it seems to operate backward of what it should. I have full vacuum advance in N,1st, 2nd, & 3rd and none in 4th. This, of course, causes the engine to race at idle. Is there a possibility that the interlock is different in '74? Does anyone know if the switch should be normally open or normally closed for a '70? My last question is if anyone that has eliminated this system would you recommend I do that. I really wanted to avoid modifying the original carburetor which does not have the appropriate vacuum provision, but given the trouble with the system perhaps now and in the future, it would be one less thing to break and potentially improve performance? Thanks in advance for any input.