Backfiring through the exhaust 1990 fj62. (1 Viewer)

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Aug 25, 2020
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alberta canada.
Good morning guys. I’ve seemed too developed a intermittent backfire through the exhaust I thought maybe it was choking itself out so I replaced the air cleaner and at the same time did the plugs rotor and cap. I checked for vacuum leaks and didn’t find any. I don’t regularly drive and decided to take it out yesterday. I was going about 60-70 mph and all of a sudden tack dropped to zero for a second and when it picked back up she fired through the exhaust (un burnt fuel before it died?) it did this 5-6 times and seemed to work itself out. The motor is the original 3f with about 250k on it. I was now thinking it may be a ground or alternator issue?? Maybe the distributor? Kind of at a loss and looking for direction. Has this happened to anyone else?

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OSS

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Jun 30, 2017
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Oblivion
Backfire is normal when an engine's ignition suddenly is cut off while driving. Unburned fuel ends up in the exhaust and ignites on the hot metal.
The problem is the ignition is cutting off for some reason. Carefully check all wire connectors and fuse connections.
It's not an alternator problem.
 
Joined
Aug 25, 2020
Messages
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Location
alberta canada.
Backfire is normal when an engine's ignition suddenly is cut off while driving. Unburned fuel ends up in the exhaust and ignites on the hot metal.
The problem is the ignition is cutting off for some reason. Carefully check all wire connectors and fuse connections.
It's not an alternator problem.
Cool. Thank you. I’ll start at the coil.
 
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Jan 4, 2011
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Vermont
If your wires are old they can get damp and short out. A quick test is to spray them with wd40 and see if it goes away. Or just put new wires in. I’ve had old wires short to the head when it was raining or even shock me if I touched them.
 
Joined
Apr 27, 2020
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Perth
would you happen to know how to test the igniter?
I had this happen to my 2F
I found it was the wires connecting to the igniter inside the electronic distributor were broken inside the insulation sheath. Right where the wire crimps to the spade connectors.
My dizzy is not OG but as the advance plate would move the wires would disconnect and connect and cause stumbling and backfire. I just cut wires opened the crimps fed wires back in recrimped and heat shrink connection. Happy days.
 
Joined
Aug 25, 2020
Messages
24
Location
alberta canada.
I had this happen to my 2F
I found it was the wires connecting to the igniter inside the electronic distributor were broken inside the insulation sheath. Right where the wire crimps to the spade connectors.
My dizzy is not OG but as the advance plate would move the wires would disconnect and connect and cause stumbling and backfire. I just cut wires opened the crimps fed wires back in recrimped and heat shrink connection. Happy days.
Nice! I’ll take a look at that. Thanks !!
 

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