New problm. RPM on chip
Posted: Thu Feb 10, 2005 12:16 pm
Think this is a new problem. Have searched the other forums and cant find anything to help me.
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MJLJ works fine on the bench.
SAW signal is changing the advance without any problem.
The indicated RPM however is jumping around all over the place.
Made up the little hysteresis circuit but still no better.
Tried a seperate power supply from a different battery, and still no better.
I then disconnected the PIP signal and the problem is still there.
Now for the interesting bit, with a seperate power supply and only the +ve and -ve attached to the MJLJ (and P.C) I still have an erratic RPM (should have non at all) turn the engine off and the RPM goes to zero, start the car again and get erratic RPM, move the MJLJ away from the car and RPM goes to zero.
My conclusion is that the MJLJ is picking up a signal that the car has around it when the engine is running as whenever it gets near the car I start to get an erratic RPM signal.
Dont know how to get round this unless there is some kind of bag or box that the MJLJ can sit in to eliminate the interference.
HELP
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MJLJ works fine on the bench.
SAW signal is changing the advance without any problem.
The indicated RPM however is jumping around all over the place.
Made up the little hysteresis circuit but still no better.
Tried a seperate power supply from a different battery, and still no better.
I then disconnected the PIP signal and the problem is still there.
Now for the interesting bit, with a seperate power supply and only the +ve and -ve attached to the MJLJ (and P.C) I still have an erratic RPM (should have non at all) turn the engine off and the RPM goes to zero, start the car again and get erratic RPM, move the MJLJ away from the car and RPM goes to zero.
My conclusion is that the MJLJ is picking up a signal that the car has around it when the engine is running as whenever it gets near the car I start to get an erratic RPM signal.
Dont know how to get round this unless there is some kind of bag or box that the MJLJ can sit in to eliminate the interference.
HELP