Tach flickers - Team Camaro Tech
Electrical & Wiring Troubleshooting electrical.

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post #1 of 9 (permalink) Old Oct 10th, 09, 05:22 AM Thread Starter
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Dave
 
Join Date: Jun 2006
Location: Vacaville CA
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Tach flickers

I noticed last night while at a stop light that the tach was flickering when the turn signal was on. ??? (This is with the headlights on)

The tach will sometimes jump 3 or 4 hundred rpm while just sitting at idle. It's the tach that changes not the engine rpm. (With headlights OFF!)

Any thoughts? Where should I start to look?

Factory OER replacement tach. MSD blaster coil ign w/8360 Dist.

Dave

Known to run with scissors....
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1969 Camaro Z/28 "clone", GMPP ZZ383, Autogear M22W, Moser 12bolt w/TruTrac 3:73.
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post #2 of 9 (permalink) Old Oct 10th, 09, 06:37 AM
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Patrick
 
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Re: Tach flickers

Not sure if you saw this..

https://www.camaros.net/techref/electrical/tachfilter/

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post #3 of 9 (permalink) Old Oct 11th, 09, 09:38 AM Thread Starter
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Dave
 
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Re: Tach flickers

I have used this same ign. system on 2 motors in the same car with the same tach. Now with 6000 miles with this combination this is the first time with this problem.

If I needed the filter mod I think I would have had problems sooner. Don't you think?

I checked grounds this morning and found nothing suspect yet.

Scratching my head,

Dave

Known to run with scissors....
__________
1969 Camaro Z/28 "clone", GMPP ZZ383, Autogear M22W, Moser 12bolt w/TruTrac 3:73.
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post #4 of 9 (permalink) Old Oct 11th, 09, 11:19 AM
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AJ
 
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Re: Tach flickers

Happens to a few people, including me.
Do you have all of the grounds on the motor and grounded to the frame and body?
I have an overly expensive autometer tach, IT IS THE BIGGEST WASTE OF MONEY EVER!

The only Mustang I'd ever own is a Fender.

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'14 5.0 Mustang
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post #5 of 9 (permalink) Old Oct 11th, 09, 11:53 AM Thread Starter
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Dave
 
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Re: Tach flickers

All wires are tight related to the coil. I have 2 braided grd. straps. One on each side of the motor running from an intake bolt to the firewall.

I will check under the dash when I have time to pull the driver side seat out.

Dave

Known to run with scissors....
__________
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post #6 of 9 (permalink) Old Sep 13th, 18, 09:42 AM
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Morgan
 
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Re: Tach flickers

Revive an old thread, I am having the same issue, I replaced the Msd 8360 distributor and put the stock one with pertronix back in, it went away and I thought I was good, went to the cruise last night and all was good until I had my left turn signal on and noticed it bouncing, turn signal off and it started acting up again.

I built one of the tach filters, no change, checked every ground I could find, tightened up the headlight switch, nothing!

My next though is seeing that it worked cold and started acting up at the end, maybe it is the voltage regulator? I already have the vr715 electronic one in there, my next step is to replace it, itís only $22

Any ideas would be helpful, btw, I did replace the tach with a brand new one, no luck

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post #7 of 9 (permalink) Old Sep 13th, 18, 10:08 AM
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Robert
 
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Re: Tach flickers

Just throwing this out there. Have you guys checked your alternator outputs? I was having all sorts of electrical gremlins when my alternator was on its last legs. Similar to what is being described with the flickering dash/tach lights. New alternator fixed everything. There may have been a grounding issue with the alternator or within the alternator. Good luck!

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post #8 of 9 (permalink) Old Sep 13th, 18, 03:49 PM
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Morgan
 
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Re: Tach flickers

Winner winner chicken dinner, I just now checked my alternator output while running, it was not charging and the battery went down to 11.5, put in my other alternator, 13.8 and the tach is working, charging the battery and off to the track tomorrow
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69 Copo 9560 ZL-1 automatic [email protected], 1.95 on f70-14 polyglas F.AS.T. Race June 2016
69 Copo 9560 ZL-1 4spd [email protected] 1.93 60ft on F70/14
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post #9 of 9 (permalink) Old Sep 13th, 18, 06:32 PM
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Rufas
 
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Re: Tach flickers

It is also essential to use the engine as the grounding buss bar for the vehicle, negative battery cable directly to the engine, then out to other areas, NOT frame first. Just FYI.
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