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View Full Version : The Micro switch next to the throttle ,has a filter capacitor.



norcimo
03-07-2016, 11:02 AM
The Micro switch next to the throttle ,has a filter cap across.

can someone tell me whats the purposes of this filter?

when removed, the idle is great...but when its connected... get I the idle hunt...sometimes..

and cold start issues too..

Bitsyncmaster
03-07-2016, 11:41 AM
It should have no effect on idle unless it's a shorted capacitor. It's to reduce the noise caused by turning the power off to the advance solenoid. Without the cap, I got a glitch of the RPM relay priming just by hitting the throttle with the engine off.

norcimo
03-07-2016, 11:53 AM
It should have no effect on idle unless it's a shorted capacitor. It's to reduce the noise caused by turning the power off to the advance solenoid. Without the cap, I got a glitch of the RPM relay priming just by hitting the throttle with the engine off.

Well that explains it.

It was shorted out... I have to find a replacement....what's the value? Cant read it off it...

Bitsyncmaster
03-07-2016, 12:01 PM
Well that explains it.

It was shorted out... I have to find a replacement....what's the value? Cant read it off it...

It's probably a 1 uf or less. Lots of cars never got the cap so it's not critical you even have it.

norcimo
03-07-2016, 12:05 PM
It's probably a 1 uf or less. Lots of cars never got the cap so it's not critical you even have it.

I have to replace it, my electrical is going crazy.
everytime I hit the brakes, the TAC jumps and sometimes the internal lights come up... or if I flash the lights.. same thing.
though its shorted, the it still filters out... so head to the auto shop and getting an inline DC noise filter.

Thanks.

Bitsyncmaster
03-07-2016, 12:35 PM
I have to replace it, my electrical is going crazy.
everytime I hit the brakes, the TAC jumps and sometimes the internal lights come up... or if I flash the lights.. same thing.
though its shorted, the it still filters out... so head to the auto shop and getting an inline DC noise filter.

Thanks.

I had noise problems when the AC compressor switched off. I put a scope on it and saw >200 volt negative spike. A zener diode attached near the compressor clutch fixed that problem.

FYI:
When an inductor (anything with a coil of wire) is depowered, the magnetic field collapses and induces a voltage usually negative. So that induced voltage drives noise in the ground and can upset electronics.

DMCMW Dave
03-07-2016, 01:49 PM
I have to replace it, my electrical is going crazy.
everytime I hit the brakes, the TAC jumps and sometimes the internal lights come up... or if I flash the lights.. same thing.
though its shorted, the it still filters out... so head to the auto shop and getting an inline DC noise filter.

Thanks.

That's not from a simple suppression cap. You have another problem, most likely a corroded ground connection or a bad connection at one of the bulkhead colored plugs. Or both.

norcimo
04-11-2016, 10:48 PM
That's not from a simple suppression cap. You have another problem, most likely a corroded ground connection or a bad connection at one of the bulkhead colored plugs. Or both.

Well, I put it back and the problem went away..its been like that for weeks now...works.