I just got done tracing that white wire from my Coil Packs all the way to the firewall. From the firewall into ECM. From ECM strait to my tach?

Whats up with this? I thought I was supposed to come across something somewhere! Even My wiring diagram tells me I should of found it.
Could this be why my tach doesn't work att all?

Thanks

I just looked at the 88 service manual. It does not show a tach filter.

Phil

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GTDude
25 years GM experience

I believe the the DIS in the later models did not need a Tach filter because the coil packs are solid state rather than moving components. If you had the pickup coil, the distributor shaft, and all the other moving parts, you would need it.

The tac filter is mounted on the end of the cyclinder head next to the ignition coil. It is about 1/2" round and 2 " long. with a wire out of both ends that has a tee shapped conector on it.
Go here and click under parts guide and do search for filter and look for the tac filter, click on it and shows you a pic of it in relation to the engine. http://www.madcownetworks.com/fiero/

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FieroDon
86 SE
87 GT (factory blue)
88 GT

WWW.Fiero.us

I dont know aboput the rest of you, but i threw mine away when it started acting up, all i did was put a jumper on the two terminals of the connector and i have a silky smooth tach. (3.4 w/ MSD 6a)

quote Originally posted by DonHager: The tac filter is mounted on the end of the cyclinder head next to the ignition coil. It is about 1/2" round and 2 " long. with a wire out of both ends that has a tee shapped conector on it. Go here and click under parts guide and do search for filter and look for the tac filter, click on it and shows you a pic of it in relation to the engine. http://www.madcownetworks.com/fiero/

Good advice if it were a 6 cylinder.

GTDude is correct, the 87 & 88 DIS systems do not use a tach filter as that function is taken care of in the ignition module. The white wire is located at pin 'A' of the ignition module and terminates at the instrument cluster plug. This wire will not go through the computer either, it is indeed a straight shot.

[This message has been edited by Indiana_resto_guy (edited 05-19-2002).]

OK?????????
If the WHITE wire is hooked up to the coil packs, and hooked up to my STOCK tach. White Wire has not been severed, Why doesn't the tach work?????

This is why You should not start a new thread for every question about the same problem.....

If the wiring is good, either the ignition module is messed up or the tach somehow was damaged. There is Nothing else on the circuit.

A ground problem between the engine and body may also be a problem.

quote Originally posted by BigNickDog: OK????????? If the WHITE wire is hooked up to the coil packs, and hooked up to my STOCK tach. White Wire has not been severed, Why doesn't the tach work?????

Do you have a signal voltage value when running from the white wire at the module?

Same question at the white wire at the dash plug if you had something at module?

If you have reference signal from the module, try a jumper wire from that point to the tach wire at the dash plug. If that works the wire is bad. (A OHM reading may take the place of jumper, make sure both ends are disconnected)

If it doesn't work then, the tach is bad (or the resistor on the tach is bad)

Thank god that is settled..........LOL. It was getting on my nerves.

Phil

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GTDude
25 years GM experience