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I have a 1995 Thunderbird LX 4.6L. A month ago it broke down due to no spark and I traced it down to the ignition module. I replaced that and it ran great for 2 weeks. Since then it’s been stored in the garage. Today I go to start it and once again no spark. If I keep trying it will eventually start after several tries. Once it’s running it runs great and will restart fine. Then I let it set for about 3 hours and again no spark. Eventually It started again and I got it back in the garage. Then restarted it 8 times. But once it sets for few hours it loses spark again. I checked all the connections on the ignition system and tried swapping out the crankshaft sensor but still no luck. No DTC’s either. Any ideas?
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After messing with it for a couple days I found a way to get it running. If it fails to start I can turn the key off then disconnect and reconnect the ignition module and it will start every time. But the next morning I will have to do it again. If I wiggle the connector while it’s running it doesn’t die giving me the impression that it has a good connection. I opened up the module and the solder joints looked good. I even tried bending all of the pins slightly up to make a better connection with the plug. But still once it cools down I have to unplug it again.
I made a quick video of the problem https://youtu.be/9ve1iZt6RnE . The module is getting 12V and is grounded. But for some reason unplugging it always works. I think I’ll try getting a used module off ebay cheap just to rule it out. Maybe a new connector. If that doesn’t work I have no idea.
It seems like your resetting the ignition module. I don’t believe its a connector issue.
see if this troubleshooting helps. In the video I noticed a yellow light on. Is it a check engine
Light?http://easyautodiagnostics.com/ford/4.6L-5.4L/troubleshooting-the-ignition-module-2
[quote=”machinist85″ post=164385]The yellow light is just the airbag light. It go’s off after a few seconds.[/quote]
Ok wasn’t sure. 🙂
Today the car failed to start again and I tested the ignition module using the guide you posted. This is what I got.
The 12+ is good.
Both grounds are good.
AC voltage from crankshaft sensor is good.
No signal from module to computer.
No signal from computer to the module but that is due to no signal from Ignition module.
The 4 wires that signal the coil packs do not pulse. They stay on solid while the key is on or cranking which struck me as weird.
If the module is bad I would have thought there would be no output. :blink:So going by the test the module is bad.
So then I tried unplugging the module and plugged it back in as before.
Now it starts and runs perfect. But in a day or two it will stop sparking again.
I have also checked all of the pins and wires on the connector for continuity and it was good.I ordered a used module off of ebay when it shows up I’ll see if it behaves the same way.
Before installing the replacement ignition module, put an AC voltmeter on the alternator output and make sur it doesn’t have more than about a half volt AC. If it has much more than that, there could be an issue with the alternator that is knocking out the ignition module.
Hope this helps.
Unfortunately my multimeter can’t check AC voltage on a DC circuit. I just get an error. I’ll see if I can get one that can.
If the alternator had bad diodes I would think it would just fry the module and not start again.Today I put another module in it. First two times it started and third time no spark again.
I tried unplugging and reconnecting the module and it starts again.
I’ve already checked the coil packs and crank sensor.
The only thing left is the computer. So the last time it didn’t start instead of the module I disconnected the battery for 30 seconds and that got it to start again.
I think unplugging the ignition module has been somehow resetting the computer. But how or why I have no idea. What would cause the computer to need reset in order to run? If it were bad I wouldn’t think it would run at all. Once it starts it runs perfect and has never died. It’s only a problem after it’s been shut off.
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