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Ok…1st –I have done the Search “tachometer” and there are at least 14 pages :sarcasm: ….. AND I did not find or I overlooked the answer on the Remote mounted Coil and ECM controlled Distributor. Each post (that I went thru) was in reference to the “old style” HEI with coil in cap and clearly marked “Tach” and “Bat” on distributor coil cap.


I have a factory tach (1987), the indash mounting bracket and the filter. I have installed in the dash and check that the “feed” wire is connected thru the printed circuit “ribbon” thru the firewall to the distributor location.


Now…. Here is the problem---where is the tach signal for the stock distributor? The stock distributor is the ECM controlled and has the external coil (2 connectors with 2 wires for each connector—label A white wire and B label pink wire). I have referred to the GM manual but I and still having problems locating a tach signal to connect the tach.
THANKS for the help.


 

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Thanks again the the wiring schematic.
All hooked-up and NO work :crazy: ....... Disconnected the tach filter and BAM!!!! working :banana: ...... Now to find another Filter :cry2: . Look on E-BAY and $55 :shock: WOW!!!! I did not pay that much for the Complete tach set-up.
 

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Thanks again the the wiring schematic.
All hooked-up and NO work :crazy: ....... Disconnected the tach filter and BAM!!!! working :banana: ...... Now to find another Filter :cry2: . Look on E-BAY and $55 :shock: WOW!!!! I did not pay that much for the Complete tach set-up.

Mine isn't working it was going to my 87 CCC CARB AND DIST, NOW ALL THAT'S GONE SO I WILL TRY THE FILTER DELETE .

Sorry for the caps????
 

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I took the filter off and mine works fine thanks for the info!!!!!!:new_ukliam2:
 
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Hey hows it going fellas. This thread isn't too old so i hope i get some action.

JJLT1 can you please repost or inbox me the picture of the hook up location on the distributor
Every thing is hooked up minus this area and can't find anything besides the coil on top of distributor set up.

Thank you.
 

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Bringing up this old thread because I'm about to add a Tach to my '87 Choo Choo and I found the "white wire with connector on the firewall"!​
 

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JB, were you able to complete your tach install? If you did, which of the 3 terminals in back of the instrument pod did you use to connect between the distributor and circuit board?
 

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Thanks JJ, I found a white wire with connector which looks exactly like the one in the picture above posted by JBzdel. My question is where does this wire lead to from this location? I trace the white wire into a harness which descends toward the passenger side of the engine compartment.

If I am interpreting correctly the information in this thread, I need to tap into the white wire on the gray coil connector. But NOT in-between the coil and distributor. This wire tap will serve as the tach trigger and should eventually connect to the Tach terminal in the back of the instrument cluster. This trigger wire can either have or not have a filter.

What is interesting is, on my 87 El Camino, which is a base model with only a speedometer and gas gauge, the harness DOES NOT have a wire nor a pin at location #17. I have seen thread claiming that there are 2 versions of these internal harnesses. Some posters say yes, others say only one version. With my setup, I believe mine is the one without a wire for the tach and pin #17. If that is correct, what is the white wire with connector as I have found in the engine compartment?

At this point, I am considering running a home run wire from the white-coil-wire-tap directly into the back of the instrument cluster. I will determine if I need to insert a filter depending on the behavior of the tach.
 

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Had a brain fart and decided to run a continuity check between white wire on gray connector at coil and loose white wire in engine compartment. Eureka!! They're one and same circuit! So, plugged tach filter into it and ran a test wire to my tach connector. Sadly, although there appears to be a signal coming through, my tach may be bad. At key ON, needle swings to 600 RPM and continues to climb. At engine start, needle swings clockwise and stops/remains at 6 o'clock position.
 

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Thanks JJ...will test Tach ground. If I do that test, then it means internally the tach itself is grounded out, correct? Because all of my other gauges, with the exception of the oil pressure, appear to be working properly, that indicates to me there isn't a ground problem with the instrument panel.

I have been looking at some of the tach repair videos on YouTube, specifically those related to a problem with resistance within a quartz component. Have you done any of these repairs and what do you think about them? The repair looks simple enough.
 

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not sure
it moves, so its not dead..
tach needs power, ground, and trigger signal to work..

everything else working may mean the dash wiring connector to the PCB is good,
but each gauge has its own 3connections to the PCB..

if it don't work, check the power first..
if it works but acts weird, check the ground first..
bad grounds cause weird things, and back-feeding thru all the lightbulbs..

I don't know enuff about those little gizmo's on a circuit board,
so I usually have someone look at that stuff for me..
but if I have some instructions that say what meter reading should be, I can do that..

there are several tach repair threads on here, try a search..
 

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Just returned from electronics store. From my online research and watching videos, I've run into a dilemma. There appears to be two different values being used for the replacement resistors--either 200 or 200K ohms. Being that a package of 6 resistors costs only a dollar each, I got both just in case the 200 ohm doesn't fix for my tach...don't want to have to make a second trip!
 
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