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Old 01-13-2012, 11:14 AM   #1
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Default Weak spark cyl 2 & 4

I have a 1995 Buick LeSabre with 3.8. Engine miss under load. Code P0300.
Has new plugs, wires, coil on cyl 4. Have replaced ICM. Still weak spark on cylinders 2 & 4. I have checked wires from PCM to ICM. Any ideas?
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Old 01-13-2012, 11:23 AM   #2
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Sounds like you are hitting all the right stuff. If you had not said you are getting weak spark, based on what you have replaced already I would suggest testing fuel pressure at the rail.

Try switching the new coil with a coil from another position and see if the weak spark moves with the coil. Wouldn't be the first time a new coil is defective.
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Old 01-13-2012, 11:27 AM   #3
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Thanks Roy. I did swap coils, weak spark stays on those 2 cylinders. Also tried a different coil with same result. Also tried another ICM. Really stumped on this one.
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Old 01-13-2012, 01:02 PM   #4
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i believe the last weak spark that was on here was the crank position sensor, dont have time to search right now.
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Old 01-13-2012, 01:13 PM   #5
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Just did cylinder leakage test. Cyl 2 & 4 with the weak spark test low. All of the other cylinders with good spark test high, in the red.
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Old 01-13-2012, 04:54 PM   #6
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Quote:
Originally Posted by bloomco View Post
Just did cylinder leakage test. Cyl 2 & 4 with the weak spark test low. All of the other cylinders with good spark test high, in the red.
That (unfortunately) makes sense. If you rule out the ignition system as you already have, it may be a mechanical issue. You might want to pull a rocker cover and inspect the valve springs, but I think you have bigger problems.
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Old 01-14-2012, 12:42 PM   #7
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Moving this one to Buick LeSabre Mechanical & Maintenance.
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