Coil Positive extra wire?
Thread Starter
|
Senior User
Joined: Jan 2003
Posts: 310
Likes: 0
Coil Positive extra wire?
I am about to install a Sunpro tach on my new truck (another 79 f250) and as usual i will connect the green to the negative side of the coil. This truck seems to have the original coil connector/cap, and has made it even more convenient by have "tach test" written right on the connector for the negative side. My question is that on the positive side there is one wire that goes back to the harness, then another that looks factory and the end is not connected to anything?
Basically the positive side of the coil has two leads, one which isnt connected? What is this for? Is it supposed to be connected anywhere? I've never seen this. Please let me know. THANKS!
Basically the positive side of the coil has two leads, one which isnt connected? What is this for? Is it supposed to be connected anywhere? I've never seen this. Please let me know. THANKS!
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
The unused lead is for an ignition noise suppression capacitor. Sometimes they were tied off the "A" terminal of the voltage regulator, and other times they were tied to the coil. Its job is to keep audio-band ignition switching from showing up on the radio.
If you don't hear your RPMs over the radio, then don't worry about it. Most modern head units have enough filtering in the first place, and most original suppression capacitors would have dried up by now anyway (electrolytic).
If you don't hear your RPMs over the radio, then don't worry about it. Most modern head units have enough filtering in the first place, and most original suppression capacitors would have dried up by now anyway (electrolytic).
Thread Starter
|
Senior User
Joined: Jan 2003
Posts: 310
Likes: 0
thank you very much! I have been searching literally all day and have found nothing on this subject at all! Has it ever come up that you know of here on this board or any other? Seems like I dont need it considering this truck doesn't even have a radio yet! Just for kicks you wouldnt have a picture of one would you? Thanks again...
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
The question does come up from time to time. I don't happen to have a picture, but someone else might. But it looks just like the condensor in a points distributor, because they're the same thing - condensor is just an older term for capacitor.
EDIT: Here's a picture I stole off the internet. These are the style that connect to the voltage regulator, so the connector and bracket look different than what you have.
http://www.allfordmustangs.com/forum...enser-ends.jpg
EDIT: Here's a picture I stole off the internet. These are the style that connect to the voltage regulator, so the connector and bracket look different than what you have.
http://www.allfordmustangs.com/forum...enser-ends.jpg
Thread
Thread Starter
Forum
Replies
Last Post
77beater150
1973 - 1979 F-100 & Larger F-Series Trucks
2
Feb 25, 2014 08:47 PM
jon69f250
1967 - 1972 F-100 & Larger F-Series Trucks
9
Sep 23, 2001 08:27 PM
