What is the proper wiring for the ignition coil for a 1984 with the iron duke? There are 4 terminals on the side of the coil. In my case there is one large pink one that goes to the ignition a brown and two blacks. Am I not supposed to have a white wire for the tach to the pick up coil. ? Obviously from the photos, someone has played with this before.
Top left we have the thick orange tanish wire Top right is black Bottom right is brown Bottom left for me is a candy cane red and white wire, this is a replacement tach filter(I believe from Rodney). If you have the stock filter this wire goes to a tiny cylinder found somewhere nearby.
Both right side wires appear to go to the distributor or the wiring for it.
[This message has been edited by AsaBergman (edited 04-27-2021).]
What is interesting is that the wire that AsaBergman says he uses for the tach filter (red & white color) – the wire just below the pink wire - goes to ground on my car – not to the tach filter. I traced the supposed Tach wire (white) back from the c500 harness and I found it cut – not connected to anything. Would having this wire go to ground from the coil cause my problem?
I "temporarily" wired in an aftermarket coil on my '84 years ago, and still haven't done it properly. I'd be too embarrassed to post a picture of the abomination.
If you saw the wiring disaster the previous owner left me with you'd see my wiring as a work of art in comparison. I'm amazed this car didn't burn. And funny how those "temporary" fixes turn into if-it-ain't-broke fixes.
snyderman, Is your tachometer not working? You never said in this post what your actual issue is.
In my picture the red-white tach wire leads to an end that appears to be electrical tape, that is the replacement tach filter I got from Rodney. It is NOT a splice I wrapped up. The black wire leads out of it to a ground, the other wire goes to the dashboard for the tach signal. The original tach filter is a small cylinder which grounds off it's case and is bolted in that area of engine.
If your tach isn't working then you've found out why.
AsaBergman My Tach is not installed at the moment as I am going to be adding aftermarket gauges so for now, not having a tach filter is really not my issue. Now that I know where the tach filter should be located and that you also have a brown and black wire going to the ignition control module, I’ll deal with that later on.
My main issue is that after reinstalling the cradle and hooking up the wiring, the car will turn over but not start. When I tried cranking for no more than a couple of seconds at a time, it burned up my ignition coil. I ordered a new coil for an ’84 from UAP (I’m in Canada) so before I install it I want to see if I can determine why the first one burnt and how it is related to my car not starting. So the first thing I looked for was the wiring and hence this thread as I wanted to find out where the 4 wires went to and from the coil to make sure they were hooked up right...
What I need to know is what else should I look at to determine why my coil burnt while cranking and what is preventing the car from starting and what should I check next. The TBI is getting fuel. It’s just not getting spark. Thank you anyone who can chime in.
Apparently I left this bit out: I'm quite sure the ignition coil grounds through the bracket it mounts to. If the bracket doesn't have a good surface mating to the engine(thick paint, excess corrosion) it can kill it and the distributor. In your pictures it does look like your engine has been repainted.
There's supposed to be a couple of ground cables going from the battery to the corner of the engine block right next to it. If these aren't there you'll have a ton of problems. As well I think having that tach wire going directly to a ground would cause issue but Ogre would have a better understanding of that than I. You should keep that wire disconnected for now.
Also as ogre said above if your coil failed it likely took the ignition module with it.
GM and other Doc's say 84 and before I-coils grounds the High-V side thru the coil mounts. 85 and later many Doc's say same in one section and not in other sections. Likely because copy/past some section from old doc's and change/rewrite others. Example this from 86 FSM...
Also in V6 Driveability section.
But in the same book in the electrical section...
So best bet is make sure Dry HEI Coils have core grounding, including Coil on/in Cap that V8's uses.
Many others still need proper mounting to ground the core. Including many "oil filled" metal case coils use on other vehicles from other brands. A coil that needs the core ground but doesn't have one can "float" at any volts cause odd problems or "break" other parts even if wired sim to the second pic and H-volt side doesn't need a ground there.
[This message has been edited by theogre (edited 04-28-2021).]
What you describe is a little over my head. Are you saying that for my ’84 it is grounded via the bolts attached to the coil frame? Also from what I understand of the 4 wires on the coil, the pink wire goes to the IGN, the white wire which in my case is black and was grounded, should go to a tach filter and then to the white wire in the C500 and the two wires going to the ICM - a black wire and a brown wire, which is positive and which goes to what you call “C”?
From FSM etc 84 Coils uses mounting hardware to ground the H-volt side. Sadly even FSM and other docs maybe wrong for 84 I-coils but don't trust is a mistake here.
Either coil wiring, No wires to the coil is a "True" Ground wire.
For "standalone" HEI coils: 2 are "12v" to run the coil then passthru to power the ICM. 1 is tack wire to tach filter and tach. 1 is ICM switch to ground.
Again, that last wire goes to a switch. Solid state version Ignition Points that are true mechanical switch.
⚠️ Warning: If the Tach wire has problems... Can "short to ground" and cause big problems. Is why my Cave, HE Ignition says Pull Tach Filter trying to find problems.
So How does second diagram works? Just trust that it works for Millions of vehicles. I believe you need to understand many things if you really want full reason why that works... Any/all of these and maybe more: the difference between Conventional current flow vs electrons flow Phasing of Coils in a Transformer. Magnetic Collapse that does the main event to generate the H-volt.
[This message has been edited by theogre (edited 04-28-2021).]
Update: I changed the coil - got one for an '84 - and cleaned the paint off the core (AsaBergman thx for the suggestion) and removed the cable meant for the tach from ground and it fired up right away. Thanks everyone for your help. .