Hi There I have been trying to get my tach (Auto Meter 3 3/4" ) to work on this MDS HEI ignition and when I fire the car up the needle jumps all over the place and eventually pins when you give the engine some throttle. As per instructions out of the box, green to the tach plug in at the HEI coil, black to ground, Red to ignition switch and white to 12vlt lighting. I checked the tach to confirm it was on the 8 cylinder setting. I assumed there was something wrong with the tach so I returned it and the replacement is doing the same thing. Has anyone ever run into this before? The iginition has a recurve kit installed but that should not be causing this should it? Any suggestions would be greatly appreaciated. Dwane Williams 72 GS
Dwane, What is a MSD HEI? Are you using an HEI to trigger a 6A(L) box? If so the tach wire (Green) goes to the tach output on the box.
Hi Larry: This ignition is your typical HEI setup, they just used MSD components inside. IE Coil, module, recurve kit, rotor and cap. There is no MSD 6A (L) box. It should be as simple as plugging the tach wire where it says tach on the HEI distributor but that does not want to work. I had a few members suggest I try and track down Ignitionman, so I'll give that a go. If I figure problem out I will let you know. o No: Regards Dwane
Dwane, It should work. You know it isn't the tach, so must be something with the distributor. I would look at your coil ground. Some use a separate wire that goes under one of the coil mounting screws, and goes to the middle prong on the triple connector on the cap. Others use a ground strap that sits under the coil, and goes to that same middle position on the cap.
Hi Larry: I thought I would put closer to this thread. After several E-mails with Ignitionman we got it solved. It turned out the power wire that goes to the BATT position on the HEI was bad. The HEI was only getting 5.5 volts and was why the tach was jumping all over the place. I replaced the wire and the tach came alive. Even better, the original hood tach that I thought was toast even works now. That ignitionman is a top notch trouble shooter. Next project.....get my gas gauge working. Take care Dwane 72 GS
