V-6
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Joined: Dec 2005
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From: St Louis MO
V-6
Ignition help needed.
My 73 350 is running like a V-6. Troubleshooting has confirmed cylinders # 2 and #7 are not firing. Consecutive cylinders in firing order. I tried a different plug, different wire and have replaced the cap and rotor with new. No change in operation.
This is an original GM ignition points style distributor, I have no idea of it's history, came with the car when I bought it in 2003.
Visual inspection of the cap after running the engine shows no evidence of fire between the rotor and the cap on these two cylinders. All others have evidence of fire having occurred. Also noteworthy, the removed rotor looked as if it had come into contact with the cap. Is the distributor at fault? Worn bushings allowing shaft to "float around?"
Suggestions?
Thanks,
knbwag
PS:I sure would like to resolve this and start leaving black marks again!
My 73 350 is running like a V-6. Troubleshooting has confirmed cylinders # 2 and #7 are not firing. Consecutive cylinders in firing order. I tried a different plug, different wire and have replaced the cap and rotor with new. No change in operation.
This is an original GM ignition points style distributor, I have no idea of it's history, came with the car when I bought it in 2003.
Visual inspection of the cap after running the engine shows no evidence of fire between the rotor and the cap on these two cylinders. All others have evidence of fire having occurred. Also noteworthy, the removed rotor looked as if it had come into contact with the cap. Is the distributor at fault? Worn bushings allowing shaft to "float around?"
Suggestions?
Thanks,
knbwag
PS:I sure would like to resolve this and start leaving black marks again!
Drifting
Joined: Nov 2004
Posts: 1,971
Likes: 7
From: Longwood Florida
Originally Posted by knbwag73
Ignition help needed.
My 73 350 is running like a V-6. Troubleshooting has confirmed cylinders # 2 and #7 are not firing. Consecutive cylinders in firing order. I tried a different plug, different wire and have replaced the cap and rotor with new. No change in operation.
This is an original GM ignition points style distributor, I have no idea of it's history, came with the car when I bought it in 2003.
Visual inspection of the cap after running the engine shows no evidence of fire between the rotor and the cap on these two cylinders. All others have evidence of fire having occurred. Also noteworthy, the removed rotor looked as if it had come into contact with the cap. Is the distributor at fault? Worn bushings allowing shaft to "float around?"
Suggestions?
Thanks,
knbwag
PS:I sure would like to resolve this and start leaving black marks again!
My 73 350 is running like a V-6. Troubleshooting has confirmed cylinders # 2 and #7 are not firing. Consecutive cylinders in firing order. I tried a different plug, different wire and have replaced the cap and rotor with new. No change in operation.
This is an original GM ignition points style distributor, I have no idea of it's history, came with the car when I bought it in 2003.
Visual inspection of the cap after running the engine shows no evidence of fire between the rotor and the cap on these two cylinders. All others have evidence of fire having occurred. Also noteworthy, the removed rotor looked as if it had come into contact with the cap. Is the distributor at fault? Worn bushings allowing shaft to "float around?"
Suggestions?
Thanks,
knbwag
PS:I sure would like to resolve this and start leaving black marks again!
are they not firing because they are fouled??? with oil or water?
Excessive liquid coming from the spark plug holes? (bad head gasket)
do a cylinder pressure test (compression test)
also check your rocker arms on cylinder #2 and #7 are the rockers moving to open the valves? (wiped out cam lobed)
And then the bone head reason... do you have the cap rotor and wires install correctly? wires firing the right firing order?
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Joined: Dec 2005
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From: St Louis MO
Thanks, we determined the misfire by using an infrared thermometer on the header pipes. Tried a spark plug on a different wire, no fire at plug. Took a test light to the cap tower, will not light the light on 2 and 7, will light it at all other cylinders, that takes the wire, the plug and fouling out of the equation.
Yes compression test showed good compression on all cylinders and well balanced.
Yes, rocker arms are all moving equally. There is definitely no spark coming from the distributor to those two cylinders.
Yes compression test showed good compression on all cylinders and well balanced.
Yes, rocker arms are all moving equally. There is definitely no spark coming from the distributor to those two cylinders.
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From: Exiled to Richmond, VA - Finally sold my house in Murfreesboro, TN ?? Corner of "Bumf*&k and 'You've got a purdy mouth'."
CI 6-7-8 Veteran
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St. Jude Donor '06-'10, '13
have you adjusted the gap on the points? Have you tried a dwell meter? Is the cam that works the points flat?
Pull the distributor and turn it by hand and make sure that the points are opening and closing for those cylinders.
Another check would be to borrow a known working distributor from a friend.
Pull the distributor and turn it by hand and make sure that the points are opening and closing for those cylinders.
Another check would be to borrow a known working distributor from a friend.
