ECU not reading sensors now
Posted: Mon May 09, 2011 1:10 pm
Hi, I have a problem and I cannot figure out how to fix it. I built my MS-II setup a couple of months ago and have just installed it into my rig. I had the ecu talking to the computer and working perfectly using the jimstim. I finished wiring the motor saturday and the gauges on my megatune dash seemed to be working fine. I have not been able to get Megasquirt to send a signal to my MSD 7al to fire the coil. I believe that I have traced that problem down. I am 99% sure that everything is wired correctly now. I have the positive side of the MSD distritutor connected to the white IGN wire and I have the negative side connected to the ground shield going to pin #2. My first attempt at wiring had the white IGN wire connected to the positive side of the distributor and the negative side connected to the ground wire from pin #18. This is the only change that I have made to anything and now the only time that my megasquirt reads any of the signals from the sensors is when the ignition is first turned on. After the initial readings show up on the Megatune dash board, any changes made to the sensors do not register with the ecu. For example: With my foot off of the accelerator pedal I turn on the ignition and the throttle position sensor on the megatune dash reads 14%. The Megatune dash continues to read 14% reagardless of how wide the throttle is opened. If I turn the ignition off, hold the throttle open then turn the ignition back on the TPS gauge on the Megatune dash reads a different number. This tells me that the wiring is correct and the gauge is in working order. I have tried connecting the jimstim to see if everything worked properly with it and the megasquirt acts the same way with the jimstim as it does with the wiring harness attached. What could I have done over the past two days to cause this? It seened to work fine on saturday and I have explained what I have done since then. I have no idea what to do now.