2.9 intermittent no spark

[Jsp1946]

Hello everyone. My daughter has an 88 Bronco II with the 2.9. TFI died the other day, so I replaced it along with the distributor. Timing set to 12 ° with spout disconnected. Truck cranks fine and idles okay, but has an intermittent loss of spark from the coil. Tested with a timing light, attached pickup to coil lead to the dizzy. When the misfire occurs, the coil isn't firing. In my experience, coils either work or they don't. I'm kinda struggling with this one- any help would be greatly appreciated!

 

[gaz]

Jsp,

I am a little confused about the way you set the timing and or are testing for Spark, where and how you identified the intermediate loss of spark.

Set timing on an engine warmed up to normal operating temperature. With timing light on #1 wire, disconnect the spout, then check/adjust timing.

 

[Jsp1946]

Jsp,

I am a little confused about the way you set the timing and or are testing for Spark, where and how you identified the intermediate loss of spark.

Set timing on an engine warmed up to normal operating temperature. With timing light on #1 wire, disconnect the spout, then check/adjust timing.

Thanks for the reply. I pulled the spout after warming up the engine, then set timing to 12 and reinstalled spout. Truck cranks and idles, but I noticed a miss. Miss was occurring randomly on all cylinders, so I connected the timing light pickup to the lead from the coil to the dizzy. Solid light when running, but when misfire occurs the timing light blinks out for a second, then resumes solid.

 

[rusty ol ranger]

Thanks for the reply. I pulled the spout after warming up the engine, then set timing to 12 and reinstalled spout. Truck cranks and idles, but I noticed a miss. Miss was occurring randomly on all cylinders, so I connected the timing light pickup to the lead from the coil to the dizzy. Solid light when running, but when misfire occurs the timing light blinks out for a second, then resumes solid.

More then likely a TFI (ignition module) failure or getting close to failure.

 

[Jsp1946]

Yep, turns out the brand new module that came with the dizzy was bad- luckily I had another new one on hand. Truck runs like a champ now.