fixing alternator noise on MS1 v2.2

[Thorkhild]

supaninja wrote:

so it looks like all my gremlins were caused by noise from the alternator. A 47uF cap to the power in and a 1pF across the boot load and i'm back in business. i probably could have gotten away with a small power cap since its shunting about .4v to the MS but it will work. got most of the idle dialed in but i ran out of gas.

Anyways one problem fixed.

I want to do the same for my setup. How exactly do I wire in those capacitors ? and are those values the ones I should use ? a 47 micro farad, and a 1 pico farad. What voltage rating should I use ?


Thanks

Eric

[miniman82]

The 47uf is just a filter cap from +12 to ground, no idea why you'd need one on boot load unless you ran those 2 pins outside the case for some reason. Would be a better idea to get get an alt that wasn't noisy, or install a common power filter from any FLAPS.

[jhoefer]

Excessive voltage ripple from the alternator could be from failing diodes in it. EMI from non-resistor or non-shielded spark plug wires can cause electrical noise. Creating a ground loop by grounding sensors to the engine block instead of at the MS can cause electrical problems.

A filter capacitor will work of course but it's covering up other problems.