 What is happing to my tach?, TAch drops out at about 4500 rpm Also drops if I use directional swithch. Then bounces all over |
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| moneysmarts |
 May 16 2026, 11:06 AM
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#21
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Member  Group: Members Posts: 183 Joined: 2-March 04 From: Central Massachusetts Member No.: 1,745 Region Association: None 
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QUOTE(Spoke @ May 16 2026, 07:00 AM)  Not sure what year your 914 is. For the '74 year the turnsignals and tachometer share the same fuse. The fuse is #9. If you haven't already remove the fuse and clean the contacts on the fuse (or put a new one in) and clean the contacts on the fuse panel. Mine is a '74. I will try that . Thank you |
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| cgnj |
May 16 2026, 11:13 AM
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#22
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Senior Member Group: Members Posts: 718 Joined: 6-March 03 From: Medford, NJ Member No.: 403 Region Association: None
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QUOTE(moneysmarts @ May 16 2026, 10:04 AM) QUOTE(cgnj @ May 15 2026, 06:52 PM) QUOTE(dtmehall @ May 15 2026, 06:03 PM) sorry, i copied the wrong url the video i saw suggested adding a 10k ohm 1/2 watt resistor to the signal wire from the coil to the tach He is using a MSD 6AL. Tach doesn't connect to the coil. It is connected to the MSD 6AL. It used to be that sometimes the MSD tach adaptor was needed to operate the tach. I have never observed that problem with both early and late tach. That is why I told him to disconnect the MSD box. Maybe the tach is or the MSD have changed over the years. Easier than pulling the bulbs out of the tach. I pulled the directional wires from the back top two holes on the tach. No change. Tach reading still drops off during acceleration when I use the directional lever. My Msd wiring has never changed in 25 years. |
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| moneysmarts |
May 16 2026, 11:59 AM
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#23
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Member Group: Members Posts: 183 Joined: 2-March 04 From: Central Massachusetts Member No.: 1,745 Region Association: None
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| moneysmarts |
May 16 2026, 12:06 PM
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#24
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Member Group: Members Posts: 183 Joined: 2-March 04 From: Central Massachusetts Member No.: 1,745 Region Association: None
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QUOTE(moneysmarts @ May 16 2026, 09:06 AM) QUOTE(Spoke @ May 16 2026, 07:00 AM) Not sure what year your 914 is. For the '74 year the turnsignals and tachometer share the same fuse. The fuse is #9. If you haven't already remove the fuse and clean the contacts on the fuse (or put a new one in) and clean the contacts on the fuse panel. Mine is a '74. I will try that . Thank you Cleaned spade connectors and replaced fuse. No luck. Still the same |
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| cgnj |
May 16 2026, 02:16 PM
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#25
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Senior Member Group: Members Posts: 718 Joined: 6-March 03 From: Medford, NJ Member No.: 403 Region Association: None
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That's an early tach. Did you pull the bulbs out of the tach?
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| moneysmarts |
May 16 2026, 02:23 PM
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#26
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Member Group: Members Posts: 183 Joined: 2-March 04 From: Central Massachusetts Member No.: 1,745 Region Association: None
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QUOTE(cgnj @ May 16 2026, 12:16 PM) That's an early tach. Did you pull the bulbs out of the tach? I disconnected the wires to the bulbs. Didn't do anything. But on a chance, I pulled the front directional bulbs out. No more drop when I use the lever,' The bulbs I had in there were 2057LL. I ordered 1157 21/5 and will try those this weekend. One of the bulbs had some corrosion on the bottom nub. And I remember years ago guys talking about feedback through filament on the wrong bulbs. Maybe that was it. |
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| moneysmarts |
May 18 2026, 07:16 AM
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#27
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Member Group: Members Posts: 183 Joined: 2-March 04 From: Central Massachusetts Member No.: 1,745 Region Association: None
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Crazy I installed the new "correct" bubs to the front directionals......and back to square on. Tach is funky when I use directional lever.
Immediately removed the bulbs.... all works fine. What is this all about? |
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| Novipec |
May 18 2026, 07:27 AM
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#28
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Newbie Group: Members Posts: 3 Joined: 4-September 24 From: Austria Member No.: 28,328 Region Association: None |
I would suggest a weak ground on your Tach, had the same issue.
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| moneysmarts |
May 18 2026, 08:02 AM
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#29
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Member Group: Members Posts: 183 Joined: 2-March 04 From: Central Massachusetts Member No.: 1,745 Region Association: None
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QUOTE(Novipec @ May 18 2026, 05:27 AM) I would suggest a weak ground on your Tach, had the same issue. I attached a seccond ground wire to the tack ground and then to the body. Didn't to anything. I that how you handled it? Or is there another way? |
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