Autosport Labs

My V3 MJLJ was working perfectly. I wanted to change my tables and upon connecting it to my laptop, I noticed I wasn't getting an RPM signal (MAP works and I can upload/download). Measuring pin 1 on EDIS not running gives a little over 12 V and I get 6.93 V when running...same for PIP input on MJLJ. Pin 3 on EDIS unit gives .01 VAC (same on SAW output on MJLJ). Disconnected PIP and SAW from MJLJ and engine runs the same. Tried switching VR leads, used a different serial cable, and hooked it up to a MegaSquirt box that I know works....still no RPM. Advance in software stays at 10 deg and the timing tape on my balancer doesn't budge when I increase RPM so I'm assuming it's in limp mode (although it runs remarkably well). Which pin on the DB-9 carries the RPM signal to the laptop? Any suggestions or troubleshooting tips would be appreciated.

While they are extremely robust, It's possible you might have a bad EDIS module. do you have access to a spare?

the DB9 connector does not have a dedicated pin indicating RPM; the RPM reading is sent via a software message along with the MAP reading and other data going between the PC software and the Megajolt.

Regards,

I think I'll rebuild that part of the harness (again) before I head out to the junk yard for another unit....hopefully it's just a wiring issue.

Thanks