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Tach help

937 views 10 replies 6 participants last post by  EricL 
#1 ·
I have a 69z that the tach reads about 3-400 rpm high across athe board. I'm not sure what caused this to happen last summer my voltage regualtor went and I installed the msd 6al about the same time. Msd can't tell me if there filter will help or not 1 tech said it would and one said it wouldn't has anyone used it? Lastly does anyone know of a reputable tach repair shop in southern nh or mass? Thanks
 
#2 ·
I have the same problem on my 69Z and am thinking about trying a tach filter to see if that solves the problem. I won't be able to get to it until next week. I will let you know if it does the trick. In the meantime, I'll be watching for the answers you get with hopes that someone knows the definitive answer.
Eric.

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69 Camaro Z28/RS, Hugger Orange w/ White Stripes, Chambered Exhaust, Endura Bumper, Protect-o-plate, Original Window Sticker
 
#4 ·
If you're running points, you'll need the filter AND the diode for the tach to read correctly.

Worked on my Sun Super tach.

Any older shop with a distributor machine would be able to "calibrate" the tach, supply them with your point distributor.

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Everett "OBJECTS IN THE MIRROR APPEAR QUICKLY UPON RAPID DECELERATION"

[This message has been edited by Everett#2390 (edited 12-27-2002).]
 
#6 ·
I had the same problem, only mine was reading 200-250 rpm high. I thought that once the car was running it was reading correctly. Turns out it was not. Found a guy here in town that used to rebuild and work on tachs but does electronic dashes now. I was able to have him clean and calibrate it. $120 worth of labor.
Gary
 
#7 ·
Could any of you guys recommending filters or diode please provide some more info. In my 55 I switched from point to Accel electronic distributor and the tach ( Sun Super II ) gets erratic around 3000 rpms. I have verified the connections and the ground. I would like to try a filter. Who/What/Where .... Any help would be appreciated.... Thanks sdtsdt
 
#8 ·
MSD 8910 is for points and OEM modules with white wire. MSD 8920 is for magnetic trigger systems which is what I think your Accel is. Diodes are available at Radio Shack part# 276-1143 or 276-1144.

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'69 RS Camaro
355 5-speed 4.11
 
#9 ·
Dave,
I just got back from having a tach filter installed on my 69. IT DID THE TRICK! The tach is FINALLY running steady and correct. The filter was from another camaro that my mechanic had laying around. If you need any of the specifics, let me know and I will get them.
Eric.

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69 Camaro Z28/RS, Hugger Orange w/ White Stripes, Chambered Exhaust, Endura Bumper, Protect-o-plate, Original Window Sticker
 
#10 ·
EricL I'm glad to hear it worked. Was your tach constantly reading high or just jumping around or both. Mine is solid but constantly high, it also doesn't stop at 0 when you shut the car off. So far 2 different msd techs have given me different answers.I hate to send it across the country to be rebuilt if just a filter is needed. I just dropped the trans off to be rebuilt today, so in 3 or 4 weeks I'll be able to try the filter if you think it will work.
 
#11 ·
Dave,
Mine was running about 1,000 rpms high at idle and when I would accelerate, it would begin to jump around. I'm not experienced enough with troubleshooting tachs to know if the symptoms you're experiencing are a calibration issue or filter issue and the last thing I would want to do is steer a fellow camaro comrade wrong. If you know someone who has a filter, maybe you could borrow it and test it out first. If it doesn't work, at least you can get the benefit of narrowing down the problem.
Eric.

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69 Camaro Z28/RS, Hugger Orange w/ White Stripes, Chambered Exhaust, Endura Bumper, Protect-o-plate, Original Window Sticker
 
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