Mid 60s inline ford, I put a new GM style (cheapy Amazon unit) HEI distributor in it a few years back. Ran fine for a few years, good spark. Took a 3 hour ride the other day and next day she cranks good but won’t start. Definitely getting gas to the carb, so next thing to check is spark. Just want to confirm my coil testing process: Getting about 1 ohm across the red batt and yellow tach terminals. Getting nothing (acting like an open) from batt terminal to rotor. Coil is getting 12v when ignition is ON. Does that fact that I’m not getting a reading at any scale across batt terminal and rotor mean possibly bad coil?
I've never failed a HEI coil but I've had several control modules fail. They are located in tthe base of the distributor and most are what is called "4 pin" style. If you replace it, be sure to apply the heat conductive stuff to the base liberally.
I'd replace the ignition module also. Plus, I'd suggest carrying an extra in case it fails when you are away from home. I buy my 4 pin modules at NAPA. They're guaranteed for several years. Never had a problem collecting with my sales receipt.
Is there any way to test the ignition module before I just go buy a new one? Is there any benefit to spending the extra money for a Pertronix unit versus a cheaper one?
I would also suggest you take a look at the bottom of the rotor, or simply replace it. The early GM HEI had a habit of the coil blowing the spark through the rotor and grounding it through the advance weight pins. The fix is to replace the rotor. The fail will be a black dot burnt spot on the bottom of the rotor near the center of the rotor. The only voltage you should see between the coil post for the rotor and the battery wire will be when the spark is sent out. The spark goes from the coil to the rotor, then out to the plugs as the rotor reaches each plug contact point. For the record, that spark at the rotor will wake your **** up, it will bite hard. Generally, the ignition module fails because the wires going to it break. The easiest test is to jerk on each wire (and don't be a wimp about the jerk). If the wire comes apart, it was already dead. If the wires are good, they won't pull apart. The wires to the module go to the pickup coil on the breaker plate. The plate is always moving, the constant flex breaks the wires.
Factory parts were mostly reliable. As said, the rotors would take the brunt of the high voltage, except on V6, which would burn thru the cap at one of the coil bolts. The later small cap V6 (Fiero and others) would get the green meanies inside. There are proper testing procedures for the HEI, but due to the simple one wire feed design and cheap, readily available parts, most just took things apart, inspected and "replace with known good part (new) and retest" parts shotgun approach. Let's face it, careful testing is the correct way to do it, but 2 cover screws, 2 or 3 quick connectors and it's ready to grab a multi meter. 4 more of the same size screws and it's out. The knockoff stuff is much less reliable. I'd get a quality cap, rotor, module and coil and swap stuff out. Anything that doesn't fix it will be a spare. Anything that does would stay in and another bought for that spares pile. YT channel Low-Buck Garage bought a bottom dollar HEI and spent too much time and effort getting it to work reliably.
Install a new module. If it fixes issue , go buy a spare. If the module doesn't fix the problem, you already have a spare.
Replaced the ignition module and the rotor, still just cranks but no start. Any ideas what I should look at next?
Did it loose a timing chain/gear (have no idea what is in the old inline Ford motor)? Pop the cap off and make sure the rotor is turning while the motor is cranking over. 12 volts while its cranking over would be a good test before dropping more money into it. After that, its the coil, then the distributor pick up.
Bench test , 12v batt , few test leads & a spark plug or 2 , Verify on the bench that it's firing or not. Then test components on bench & specs No point moving to vehicle engine Until Bench testing producers spark, Does not need to be installed in engine. Did not see what Ford in line 6, Will 300 6 fit ? Do you have pick a part , $30 300 6 75- 92 ish
Usually a module failure is heat related, from my experiences getting stranded with a HEI car. ****s out, starts fine when it cools off. I had one that was confounding. I could stop doing errands, but for less than 10 minutes. Go for 15 minutes and it was a **** shoot if it would start, until the engine was dead cold.
Check the wires from the pickup to the module. They can break from the constant back and forth motion from the vacuum advance.
On Gm since 78 to present I have only had like 6 or so modules go bad I did fleet , Gm , Ford Mopar My experience Usually the Gm either good or bad for the module OEM one. Ford & Mopar they would intermittent Work then Not
Man I’m at my wits end with this thing. Same situation, cranks good but no start. Since the last time I posted about this… Replaced the ignition control module Replaced the rotor Replaced the plug wires Put in a whole new distributor, that includes a new IGM, cap, rotor and coil. Replaced spark plugs (Autolite 45s gapped to 44) Additional details 1966 240cid Cheapy $80 Amazon HEI style distributor EZ Wiring kit done by me about 5 years ago Never had a no start issue, or wiring issue in the last 5 years Day before no start- 300 mile round trip at highway speeds with zero issues. Come out the next day, and it just cranks. Tested again: Fuel getting to carb 12v on pink wire going to the distributor What am I missing here???? I feel like I’ve replaced pretty much everything at this point
You don't mention replacing the coil lead. Maybe you already did it when you did the plug leads....???
Stock Ignition Switch ???? [could this be for a Ballast setup with 2 ign positions ?] Unplug the starter solenoid and get somebody to hold the switch in the cranking position and see if the pink wire has 12v Or hotwire from the battery to the HEI and try and crank it. This will confirm or eliminate the harness / switch If it still doesn't fire ,it could be the distributor or fuel tip a cap full of paint thinners down the carb and repeat. [thinners vaporize really easily]
Stock ignition switch. Eliminated the ballast when I changed it over to HEI. If I already confirmed that the pink wire going to the power terminal on the distributor has 12v when ignition is in the ON position, what would those other tests tell me? I poured a little gas in the carb, no difference
A couple things simple to try. Run a jumper wire from the positive battery post directly to the distributor. If still no start, pull a plug and with the plug wire connected to it, ground the plug body to the head and crank the motor. Need a helper for that. Then, if still no start, pull the cap and crank the motor to see if the rotor turns. And not wanted to sound sarcastic, but the first thing we learned in auto shop cl*** is to make sure it has gas in it, and actually getting to the carb.
There has to be power to the ignition system while the motor is cranking over. If you loose the power to the dist while cranking over, its not going to start. You have to have someone hold the key in the crank position and be sure you are getting 12 volts (or close to it) to the power lead going into the distributor. Mike has a good way to be certain the distributor is getting power. Then follow his procedure.
Will try that tomorrow morning. If it’s not getting 12v at the distributor while cranking, what could likely be the culprit?
Hard to say why. I run an EZWire harness in my Ol' Furd too. Its a nice harness, and its been reliable. But there's no way to know if there would be differences in the way your was wired compared to mine. I also used to have aGM style HEI distributor in my 300 inline. An Amazon/Shanghai special. It ran but I did have a few problems with it. First the mechanical advance began to act jumpy, then the vacuum advance pod sprung a leak. Piece of ****. It has a Ford TFI unit in it now.
Do the test first. Determine if that is the problem. It may be a heat related deal that will only fails after things get hot. That ignition system is going to need, at minimum, 9 volts to power the coil while the motor is cranking over. If the voltage is under 9 volts, there is a bad connection, or a bad wire someplace on its run. If you still have the instructions from the wiring kit, you may want to see if there is a specific wire or relay that sends power to the distributor only while the motor is cranking over. If you don't have the instructions, or it doesn't show the separate wire, that power likely transfers through contacts inside the switch. How the system operates is in the 'generally speaking' section below, adding it was an after thought. Your original ignition switch would be the next thing I would look at. That could easily be making interment contact on the terminals inside of the switch. Depending on the switch you have, there may be an internal terminal inside of the switch to feed battery voltage to the distributor only while it is cranking, or that power could have a separate terminal on the outside of the switch of the switch, or that power come from another source, which should show up in the wire harness diagram. Generally speaking, the wire terminal that plugs into the HEI distributor to power the coil usually has 2 wires connected to that one terminal. One of those two wires in that terminal comes from the ignition power off the key switch, the one you tell us has 12 volts while the switch is turned on. The other wire on that terminal only has power when the starter is cranking. If there is no power while the switch is in the spring loaded crank position, the coil has no source of power for the ignition system. Every ignition system I ever encountered has power to the coil while cranking, if the power is not there, you need to find out why its not. If the wiring diagram does not show a specific power wire for that purpose, that power often comes directly through terminals inside of the ignition switch.
Pickup coil went bad on an ot Ford 5.0 I have. Had to dis***emble the distributor to replace it. Fortunately it failed while in the garage. Failed the Module on a Chevy 350. Easy to change.
Some ignition switches have no power in cranking position and rely on the R post on the solenoid. Some ignition switches have 2 ignition positions [Ign 1 and Ign 2],one is for the cranking position byp***es the ballast When the engine is cranking there is enough voltage drop from the battery that combined with the ballast will kill the ignition. [so the switch /starter byp***es the ballast] Just get someone to hold the switch in cranking position [with the starter unplugged] and check to see if the HEI is receiving 12v+ If your ignition switch is as I described ,try and run a wire from the "R" post on the starter solenoid [the R post is dead when the starter is not engaged] If you have a mini starter without a "R" post, you can run a wire from the "S" post wire to the HEI , BUT you must add a 5a Schottky diode to this wire so the ignition doesn't backfeed and keep the starter engaged A Schottky diode has minimal forward current voltage drop [0.2v]
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