quick advice on tach wiring

NOSNotch

Founding Member

Oct 20, 2001

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South Jersey

Jun 3, 2006

#1

• Jun 3, 2006

• #1

whats up guys. my buddys havin a problem with his tach. i checked all his wiring today and it seems to be wired up right. red on switched 12v, black is grounded, white going to light switch hookup and green is going to tach output on msd box. when he turns the power on the shift light lights up and stays lit. anyone know whats causing this? thanks

kevin

 

8

86bluecobra

Advanced Member

Dec 20, 2004

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B.C. Canada

Jun 3, 2006

#2

• Jun 3, 2006

• #2

with msd box's some times you need the msd tach adapter for the tach's to work. I know i had to buy one so my factory tach would work.

 

85_SS_302_Coupe

it sucks (I know) to be on the receiving end

15 Year Member

Nov 11, 2003

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Northern KY

Jun 3, 2006

#3

• Jun 3, 2006

• #3

I've never ran my tach off an MSD box...i've always run it straight from the coil.

 

Rynb15

Member

Nov 21, 2005

132

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18

Jun 3, 2006

#4

• Jun 3, 2006

• #4

ya, just tap it into the wire off the coil and see if that makes it work. If not it will only take you 5 min to do anyway.

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

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Jun 4, 2006

#5

• Jun 4, 2006

• #5

It seems to me that MSD instructions say to run the tach wire off the box and not the coil. Check their instructions (PDF on their site). Does the tach work (and just the shift light is jacked) or does the tach not work and the light has a mind of its own?

Good luck.

 

B

brothergoat5

New Member

Sep 11, 2005

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Jun 4, 2006

#6

• Jun 4, 2006

• #6

NOSNotch said:

whats up guys. my buddys havin a problem with his tach. i checked all his wiring today and it seems to be wired up right. red on switched 12v, black is grounded, white going to light switch hookup and green is going to tach output on msd box. when he turns the power on the shift light lights up and stays lit. anyone know whats causing this? thanks

kevin

Click to expand...

More than likely you need a tach adapter and the msd part number is 8910. I wouldn't suggest trying to get the signal off of the coil (-) with any aftermarket ignition installed. Most are putting out 400v or more to the coil.

 

NOSNotch

Founding Member

Oct 20, 2001

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South Jersey

Jun 4, 2006

#7

• Jun 4, 2006

• #7

other than the shift light the tach works fine. reads correct and the illumination light works, just the shift lite is the problem. any other suggestions? im leanin away from a tach adapter just b/c two of my friends have this problem both with 5.0 cars and mine is hooked up the same way w/o this problem. thanks again

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

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Jun 4, 2006

#8

• Jun 4, 2006

• #8

If the tach itself works, it seems like the proper signal is reaching the tach. Could it be a tach light issue alone (and not a hook-up or install issue)? Kinda seems that way to me.

Good luck.

 

GearHd6

Member

Jul 19, 2005

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Ashford, CT

Jun 4, 2006

#9

• Jun 4, 2006

• #9

HISSIN50 said:

If the tach itself works, it seems like the proper signal is reaching the tach. Could it be a tach light issue alone (and not a hook-up or install issue)? Kinda seems that way to me.

Good luck.

Click to expand...

Yeah. Im with you on this one HISSIN50. Sure sounds like a problem with the light itself or the wires that go from the light to the tach.

 

89Notch

Founding Member

Oct 21, 1999

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MSU

Jun 4, 2006

#10

• Jun 4, 2006

• #10

Yea, the shift light should only receive power when the rpm is past your set point, is it set at like 0rpm? If not I would maybe return it for another

 

B

brothergoat5

New Member

Sep 11, 2005

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Jun 4, 2006

#11

• Jun 4, 2006

• #11

Get it exchanged with another one. If it still not working properly you probably need a tach adapter. What kind of shift light is this? Have you gone to the manufactures website to see if they have encountered this already? They might have a fix.

 

NOSNotch

Founding Member

Oct 20, 2001

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South Jersey

Jun 4, 2006

#12

• Jun 4, 2006

• #12

its an autometer light and tach. ive searched around for an answer and havent found anything yet. i've got another one at the shop i think im gonna try. if that doesnt work just gonna tell my buddy to return it. thanks for the advice guys