I just finished up my TPI swap last weekend and while doing some test and tuning the check engine light came on, expected. I checked the codes and had a code 42. The strange thing was that the car didn't show any of the obvious signs of module failure. Just to be sure I replaced the module since the old was in the dist. for quite some time and drove it again. After two more runs I got the 42 again and still the car ran properly. I went through and checked the wiring, grounds and anything else I could think of and all was good. A friend said that it was the MSD and that he had several cars in the past come in his shop with a code 42 and after disconnecting the MSD the code never came back. I took the car to a cruise yesterday and got the chance to really drive it for the first time and sure enough, after about 30 minutes at speeds of 55-75mph the 42 came back and still the car ran fine. My question is why is it doing this and is there a way to have the MSD without the code 42? Has anyone else had this sort of problem? A couple of guys at the cruise ran into this same problem but had no idea of how I might correct it, they just removed the box. I wonder why MSD doesn't mention this in their literature . Also, does any other brand of ignition box cause this problem?

 

I have never heard of that issue with the MSD box, but if your initial timing is set too far away from the stock 6 degrees, it could throw the code. Also if you have a bad wire that goes to the distributor or the timing disconnect wire, that is not making a good contact, that would throw the code too.

 

I've got timing set at 8 degrees, that shouldn't be too much. All the wiring checks out fine as well. The first person that told me about this had a lengthy conversation with MSD about it and they claimed that they were aware of the situation. When he asked why nothing was stated in their literature about it they had no answer.

 

Talked with my buddy today about this and got a bit more info. Seems that this only happened with 90-92 speed density cars. He never encountered this problem with any 85-89 MAF cars. He also owned a 90 Formula 350 and tried everything from replacing components to remounting, rewiring and re routing and still had the 42. He did state that after mounting and routing the MSD and wiring as far away from the ecm as possible it took longer to trigger 42 but it still happened. This particular Formula ran fine even with the light to the tune of 7.60 in the 1/8th.