Hey guys . like the ***le states I got no power on my yellow wire to the coil positive coil negative- ground -yes Power into hy-fire box on red wire Mallory unilite distributor power in on red wire Ground on brown Nothing on green ( signal back to hy-fire box ) tried a new module in distributor- same thing . All fuses are good . I don’t get it , thing has been running like a dream untill about 2 hours ago I know the unilite distributor modules are not built so robust but I thought the hyfire boxes where pretty good I need help !!
You won't see any + voltage at the coil with a CD ignition box. Ask me how I know. Have you turned the motor over to see if you have spark at the plugs?
No spark out of the coil confirmed with spark tester no power at positive of coil covering the “ eye “ on the Mallory module in the distributor changes nothing . again 12 volts into Mallory hy-fire Ground present 12 volts at ballast 6 volts at other end No power out of hy-fire to positive of coil Both negative and positive to coil come out of the box . 12 volts at unilite distributor Ground at distributor Nothing on green signal wire coming out cranking the engine NO voltage at coil No pulses on positive or negative thing was purring like a kitten Then **** all over like a mangy barn cat !!!
I had to hunt up the instructions https://do***ents.holley.com/690.pdf You were looking at the right instruction sheet? They have a **** ton of different diagrams depending on what rig you are putting it on or what distributor you are running. I'm no seeing a Yellow wire would that be their Orange wire?
Unlight needs a Ballast on positive power side , if not will take out eye/module. diagnose , A few jumper Wires , By p*** box Hook Unlight direct to coil, see if start or Firing , check with another coil ( box still by p***ed) Or can Pull distributor ,bench test distributor, coil, Coil wire ,one spark plug wire, spin with fingers Ground spark plug & distributor Power to coil , & Unlight Neg from coil term to Unlight
Until the engine is turned over and the MSD or any CD box is "Hot" there won't be a voltage reading at the coil. Just turning the switch on won't show voltage at the coil. you already replaced the Unilite, by p*** the Hyfire, and see what you get. I have seen this movie.
With the engine cranking I have no voltage at the coil tomorrow I will check the hy fire box , I have 12 volts on 1 wire I must be missing either battery voltage or switched voltage I’ve bathed , eaten , had my dessert and now 3 deep in some yummy , yummy Canadian rye whiskey . so it seems this will be a tomorrow issue . I’ll report back , thanks guys .
This is the reason why so many prefer points and condenser. Problem? Simple, static, common diagnostics along with common easily fixed issues. Black/mystery/CD box, the standard old tests are not valid and there are no new standard static tests to diagnose. It's why when a mechanic goes to the service manual and reads "replace with known good unit and retest" they get angry. If you can't do something safe and easy to cause the box to trigger a spark or byp*** it and cause a spark, it's causing you to spend money and HOPE that it works. It's why the OE stuff, especially GM HEI are preferred over aftermarket. Power in and all connected? You will get Spark 99,999 out of 100,000 or replace a simple module or coil both available cheap and all over, or it's a strange rare wiring or pickup, also both replaced cheap and easy. It's still replace with known good, but it's more reliable, common cheap shared parts, not 50 versions.
The hy-fire box **** the bed . 12 volts constant 12 volt keyed Ground power at distributor Ground at distributor Trigger wire continuity back to box negative at coil No positive out of box . By-p***ed the Hy-fire box and she fired right up and purrs like a kitten . It threw me for a loop as this thing has been running fantastic the last few weeks . I guess it knows it’s for sale and just doesn’t want to leave my loving caress
No ballast resistor to unilites , ballast resistor to coil . Don't need the ignition box for the coil to work , byp*** the box, if it runs , the box is bad .
Sorry Mis spoke on where the ballast go's, I knew there was one in wiring & ballast is for Non resistance / ballast coil
A CDI ignition works very differently from other ignition systems. Other systems send some current through the coil for a while to build up an electromagnetic field in the coil, and then turn that current off (by opening the points for example) to make the magnetic field collapse and cause a several hundred volt pulse in the primary winding. The secondary winding with perhaps a hundred times more turns inside the same magnetic field then gets a hundred times higher voltage pulse which will be enough to make a spark. The CDI system byp***es all the early stages of that. It charges an internal capacitor to several hundred volts, and when it's time to make a spark it discharges that through the ignition coil primary. Instead of the slow magnetic field buildup it gives the coil a swift kick in the nuts at several hundred volts which the secondary winding transforms into a ~100 times higher voltage for the spark. A normal multimeter is way too slow to detect that short pulse, we are talking a few milliseconds at most. Multimeters usually update the display three times per second, and even so they may need a few updates to get a stable reading.
The wire coming out of the hy-fire box with a test light or meter connected did nothing , zero . im thinking of bringing the box to work and take it apart , really can’t be much inside . I’ve replaced transistors , mosfets , and the like on boards in electric forklifts . The one that pisses me off is when they goop the inside of the controller with silicone or epoxy so you can’t fix anything !!!! anyways , it’s junk right now , pretty sure I can’t **** it up any worse
Used to be a place on the net called " century performance" they had pages upon pages of Mallory ignition tech , troubleshooting , installation , etc . Pretty sure they're gone now , might someone have stored all that tech ?
The Jalopy Journal
