mess

I'm trying to check my guarding system to see if a warning buzzer will come on when the motor gets hot. I unscrewed the sensor out of the exhaust manifold,turned the key on and put the sensor in boiling water. No alarm went off. I then took my buddy's ecm and plugged it in and ran the same test. The result was the same. I'm checking this because I had a new motor overheat and Merc replaced it. When I heard the buzzer the temp gauge showed 280+. That was the only warning the guarding system gave me. I've read threads how the guarding system shuts down before it gets to hot. That did'nt happen with my motor. I would appreciate any help.

GOODT

the sensor needs to be grounded inorder to work best way to test is with the mercury/spx computer

what gardian does is either cut back useable power or shut down mtr in order to minimse any damage..

Dave_N

I made a tester type thing from a 200Kohm potentiometer. I stuck it a little project box and used a connector from an old exhuaust temp sensor to connect up to the engine harness. Using something like this you can simulate any temp you want and check entry to and exit from Engine Gaurdian Mode. Its better if you have a scan tool to see what the simulated temp is. It should go into Gaurdian Mode at 212 degrees and go back to normal operation at 155 (Or about there I can't remember exactly).

Dave