Can you test a tach filter?
Thread Starter
Pro
Joined: Jan 2005
Posts: 539
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From: Twin Cities Minnesota
Can you test a tach filter?
Can you test a tach filter? Like putting a meter across it? I know it is a couple resistors and capacitors but not sure what to look for (I am a harware saleman not an electrician 
)
I put an OHM meter on mine and it reads 17.43 on my meter.
Dont know if that means it is good or bad or if you can even check it with an OHM meter.
)I put an OHM meter on mine and it reads 17.43 on my meter.
Dont know if that means it is good or bad or if you can even check it with an OHM meter.
Drifting
Joined: Oct 2003
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From: Kerrville Texas
Race Director
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From: San Diego - Deep Within The State of CONFUSION!
Originally Posted by kona
Race Director
Joined: Sep 2002
Posts: 10,362
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From: San Diego - Deep Within The State of CONFUSION!
Originally Posted by kona
Paul, you really expect it to be accurate?
Kona
Kona
It would be nice if it was *close* though. It reads several thousand RPM higher than actual. Instructions said that with key ON, the tach should zero out. It does indeed do that at least!
Start up the stroker, and the 900RPM idle shows to be 1850 and at 65MPH, it reads 4500RPM to 5K. so when I get on it, the tach actually swings past the redline, and back around to the 7:00 position or so
If it wasn't such a pain in the **** to pull it back out, I'd replace that circuit board again. But it's just not worth it to me when I can buy a Sun tach for 50 bux.
Le Mans Master
Joined: Oct 2005
Posts: 6,247
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From: Glen Allen, VA
yours sounds like it reads about the same as mine does, about 4500-5000 going down the interstate. I have traced the light brown wire going to the tach side of the HEI, but there is no filter btwn it and where it goes into the wire harness loom on the firewall. I've seen mention of the filter being on the intake, but my wire just goes from the HEI, straight back towards the back of the car. Anyone have any ideas?
Race Director
Joined: Sep 2002
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From: San Diego - Deep Within The State of CONFUSION!
Originally Posted by C3 4ME
yours sounds like it reads about the same as mine does, about 4500-5000 going down the interstate. I have traced the light brown wire going to the tach side of the HEI, but there is no filter btwn it and where it goes into the wire harness loom on the firewall. I've seen mention of the filter being on the intake, but my wire just goes from the HEI, straight back towards the back of the car. Anyone have any ideas?
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Racer
Joined: Nov 2004
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From: Granbury TX
Originally Posted by 76project
Can you test a tach filter? Like putting a meter across it? I know it is a couple resistors and capacitors but not sure what to look for (I am a harware saleman not an electrician )
I put an OHM meter on mine and it reads 17.43 on my meter.
Dont know if that means it is good or bad or if you can even check it with an OHM meter.
)I put an OHM meter on mine and it reads 17.43 on my meter.
Dont know if that means it is good or bad or if you can even check it with an OHM meter.
Thread Starter
Pro
Joined: Jan 2005
Posts: 539
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From: Twin Cities Minnesota
Lucky, thanks again for the info, and also the pictures 
. I am taking things apart to clean up my engine and your picture helps me trying to figure out a couple things. Two questions if you don't mind. First are your weights stock or replacements, I see numbers stamped on them, mine do not have any numbers and look kind of cheap like they may be aftermarket replacements. They dont really look flat. Second, (sorry for the low res. pictures of mine, crappy camera) 
my top weight does not sit tight against the center cam like the bottom one. The spring does not hold it against the center cam, just kind of floats in the middle. It does contact the cam as soon as you turn the advance but seems like it should be in contact always. Is yours tight against the cam?
Thanks again.
. I am taking things apart to clean up my engine and your picture helps me trying to figure out a couple things. Two questions if you don't mind. First are your weights stock or replacements, I see numbers stamped on them, mine do not have any numbers and look kind of cheap like they may be aftermarket replacements. They dont really look flat. Second, (sorry for the low res. pictures of mine, crappy camera) my top weight does not sit tight against the center cam like the bottom one. The spring does not hold it against the center cam, just kind of floats in the middle. It does contact the cam as soon as you turn the advance but seems like it should be in contact always. Is yours tight against the cam?Thanks again.
Pro
Joined: Nov 2004
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From: Flower Mound Texas
Originally Posted by SanDiegoPaul
That's where I got mine. Of course, the tach still isn't accurate even w/the new circuit board from MidAmerica. But it swings back and forth real purddy like!
