85 Olds Firenza, Locate Tach Wire?

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Forum Name: Vehicle Wiring Information & File Requests
Forum Discription: Request Car Alarm, Car Stereo, Cruise Control, Remote Starter, Navigation, Mobile Video, and Other Vehicle Specific Wiring Info, Manuals, Tech Tips
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=67853
Printed Date: May 09, 2025 at 9:08 PM

Topic: 85 Olds Firenza, Locate Tach Wire?

Posted By: xttech
Subject: 85 Olds Firenza, Locate Tach Wire?
Date Posted: December 06, 2005 at 11:20 PM

I am trying to setup a remote starter on my beater 85 Olds Firenza.

The ignition coil is pretty old and not readable for the negative side. The wire is supposed to be white and the wires are either red, brown or black.

Stupid question, but using a voltmeter. is there a way to find the negative post of the igntion coil?

thanks

Replies:

Posted By: Mike M2
Date Posted: December 07, 2005 at 4:40 PM

Those old GM cars used some poor plastic to shield the wires. Too many times i've seen the white wire turn tan and brown. My bet is thats it. I bet the red wire used to be pink too....

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Mike M2
Tech Manager
CS Dealer Services

Posted By: xttech
Date Posted: December 07, 2005 at 5:07 PM

THanks Mike M2

I have found in my manual, supposedly, I can use the white wire coming off the distributer. I am going out right now, to try that wire.

If that doesnt work, I noticed on one of those wires going to the coil, white tape wrapped around the one wire for about 4 inches in length, so I am thinking that might be the white wire on the coil I am looking.

Xttech

Posted By: xttech
Date Posted: December 07, 2005 at 9:09 PM

Well, looks like I have found a good tach wire now..off the white wire going to the distributor.

My only problem now, it starts, but the starter stays engaged dragging, then remote control shuts car down. From the manual, it appears this might be caused by a weak tach signal. or its needs to be tach adjusted again. I tried tach adjustment again and still the same.... I also noted off the distributor there is a PURPLE / white wire and this poss can be a better tach signal as it goes to the engine crankshaft sensor. I am going to try switching this out and see if it is the cause.