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Tach not working, ideas??

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Old Sep 30, 2003 | 08:19 PM
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From: Littlefield, Texas
Tach not working, ideas??

Hasn't worked since Haltech install

Leading and trailings are firing. I've used a different factorty tach and still the tach doesn't work. Is this a Haltech issue or maybe just 2 bad tachs or a bad circuit board on the guage cluster.

I do not use the factory oil, temp, or boost gauges so they are disconected. Could this cause the tach to not work in some wierd way?

Any ideas would be helpfull.

Thanks
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Old Sep 30, 2003 | 09:51 PM
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From: Rohnert Park CA
Trailing coils are not firing... do you have the haltech driving the stock trailing coils???

Its either that or maybe you removed the harness that supplies the tach signal to the dash from the engine compartment???

The Yel/blue at the trailing coils is the summed tach signal for the tach in the dash (as well as the power steering, and everything else in the car that uses tach).

Last edited by Icemark; Sep 30, 2003 at 09:54 PM.
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Old Sep 30, 2003 | 10:44 PM
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Are you 100% sure that the trailing ones are firing?

Did you cut the yellow tach wire coming from the coil pack?
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Old Oct 1, 2003 | 05:53 AM
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From: Louisville KY 40299
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Old Oct 1, 2003 | 10:00 AM
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I'm 100% sure they are firing. I do have a seperate ignition box on each of the trailing coils though. I'll try to wire it up directly to the coil. The Haltech is reading rpm's just fine. Maybe something is unplugged, i'll check it out tonight.
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Old Oct 1, 2003 | 02:54 PM
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From: Louisville KY 40299
Originally posted by West TX RX-7
I'm 100% sure they are firing. I do have a seperate ignition box on each of the trailing coils though. I'll try to wire it up directly to the coil. The Haltech is reading rpm's just fine. Maybe something is unplugged, i'll check it out tonight.
The haltech will read RPM's off the CAS though. So long as the engine is spinning, its going to get a reading. Your tach gets it signal from the firing of the trailing coils.

My tach wasnt working for a long time and I just recently got it fixed.
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Old Oct 2, 2003 | 08:12 AM
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What was wrong with it? Maybe same problem.
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Old Oct 2, 2003 | 11:49 AM
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what would be the symptoms of the trailing coil not firing?
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Old Oct 3, 2003 | 02:31 AM
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^
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Old Oct 3, 2003 | 06:26 AM
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From: Louisville KY 40299
Originally posted by West TX RX-7
What was wrong with it? Maybe same problem.
I had physically severed the stock wires and then connected them with the Haltech wiring and switched 12v+

People later told me you didnt have to wire the tan wires to anything..and to just leave them uncut. They also said to splice into the pink and white wires instead of severing them. I did that and it worked...but it was kind of sketchy. Sometimes my tach would work, sometimes it wouldnt ( I think the problem was a bad connection from where I tried to reconnect the tan wires back ).

I finally got it working when I just spliced the W/B wire into the Pink, the G/B wire into the White, and also spliced switched 12v+ into both of the Tan wires.




Also, how are you sure your T coils are firing?
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Old Oct 3, 2003 | 06:27 AM
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Originally posted by NA_VersionFC3S
what would be the symptoms of the trailing coil not firing?
You wouldnt feel any difference ( at least I didnt... ). The only way I could tell was because of the obvious fact that my tach wasnt working, and the difference between my plugs. You can normally see a little ring from where the spark has arced, but my T plugs were both just solid pitch black.
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Old Oct 3, 2003 | 07:43 AM
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Can you post a pic of your wiring harness stock side both plugs going into the trailing coil?

That'd be really helpful. Odds are a certain wire isn't connected.
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Old Oct 3, 2003 | 08:42 AM
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From: Littlefield, Texas
Originally posted by adamlewis


Also, how are you sure your T coils are firing?
Test light bulb blew out when testing the secondary coil. Not meant for that much juice.
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Old Oct 3, 2003 | 08:48 AM
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From: Littlefield, Texas
Originally posted by Josepi
Can you post a pic of your wiring harness stock side both plugs going into the trailing coil?

That'd be really helpful. Odds are a certain wire isn't connected.
I'll take many close ups of the ignition setup and post them here after lunch. Great Idea Josepi! Thanks!
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Old Oct 3, 2003 | 12:15 PM
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You wouldnt feel any difference ( at least I didnt... ). The only way I could tell was because of the obvious fact that my tach wasnt working, and the difference between my plugs. You can normally see a little ring from where the spark has arced, but my T plugs were both just solid pitch black.
How would you not feel a difference. If they wern't firing, wouldn't that mean that you were only running on 1 rotor?

How can you test them? And also how did you fix the problem? Just get a new trailing box.

Thanks.
Tim
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Old Oct 3, 2003 | 02:35 PM
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From: Louisville KY 40299
Originally posted by NA_VersionFC3S
How would you not feel a difference. If they wern't firing, wouldn't that mean that you were only running on 1 rotor?

How can you test them? And also how did you fix the problem? Just get a new trailing box.

Thanks.
Tim

No. Youre trailing plugs are the top plugs on each rotor. They dont do much aside from help clean up the last bit of combustion. If you ever get a chance to see a rotor housing, look at how small the trailing spark hole is.

I posted how I fixed the problem earlier in this thread.
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Old Oct 3, 2003 | 09:19 PM
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Didn't you post how to fix it if you have a Haltech though. I don't have a Haltech.

Tim
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Old Oct 4, 2003 | 12:37 AM
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Originally posted by NA_VersionFC3S
Didn't you post how to fix it if you have a Haltech though. I don't have a Haltech.

Tim

Get a DMM and see where your problem is. Its really really rare for a coil pack itself to fail.
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Old Oct 6, 2003 | 11:10 AM
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I took some pics this weekened but forgot to bring my camera back with me this morning to work. I'll bring it after lunch but I did notice a yellow wire with a blue or black stripe was not connected to anything. The orange and blacks from the coils are connected.
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