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Symptoms of a worn dist. cap/rotor?

Silly question to some. I'm not in town, my wife called. She took the 911 out to run a few errands. Car hasn't been driven in a few weeks. She said she was getting a nasty backfire through the airbox strong enough to make the pop off valve slam up and down when she started the car. It settled to a somewhat, but not bad idle, but it was hesitating when she gave it gas. I looked at the cap/rotor awhile back since i had not replaced it in about 5-7 years, about 20,000 miles and the rotor looked worn and the cap had carbon on the contacts. Could it be this simple?
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Old 01-13-2012, 10:34 AM
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20k on a cap and rotor is damn good, plus it's a great place to start. How old are the plugs?
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Old 01-13-2012, 10:45 AM
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Plugs, wires, cap, rotor, all same vintage. Just hate changing that one plug....you know which one I'm talking about.
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Old 01-13-2012, 10:54 AM
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Quote:
Originally Posted by Starless View Post
Silly question to some. I'm not in town, my wife called. She took the 911 out to run a few errands.

Car hasn't been driven in a few weeks.

Condensate inside the distributor cap...


She said she was getting a nasty backfire through the airbox strong enough to make the pop off valve slam up and down when she started the car. It settled to a somewhat, but not bad idle, but it was hesitating when she gave it gas. I looked at the cap/rotor awhile back since i had not replaced it in about 5-7 years, about 20,000 miles and the rotor looked worn and the cap had carbon on the contacts. Could it be this simple?
Washed it just before putting it away..???

Warm engine, it goes away.
Old 01-13-2012, 01:51 PM
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If every thing has 20k on it I would go for a new rotor, cap, plugs, and air filter. I had a nasty back fire untill I changed those things out and now it's running real nice.
Old 01-13-2012, 03:15 PM
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I'm with Dave on this one. I just did the cap, rotor and plugs. The lagging is gone along with the embarrassing backfire!
Old 01-13-2012, 06:06 PM
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Wwest, no, it's filthy, haven't washed it in months. Well the plugs, wires, cap, and rotor are due anyway, may as well start there. I'll order them from our host and hopefully they'll be home by the time I get there.
You kind of get spoiled by new cars, they go for almost 100K miles before you even think of changing out those things.
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Old 01-14-2012, 03:44 AM
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Hi everyone, to touch on this...

How long do you expect a cap and rotor to last on these cars?

My 82' SC has developed what appears to be a slight missing feeling. It's very noticeable when cold, is almost entirely gone when at operating temperature. I pulled the cap and rotor today and noticed oddly enough that only half of the nose of the rotor appears to be blackened (I though that was odd) and very black with some buildup on it. I used a little 600 grit to get it clean again and also brush off the inside of the cap as well and went for a drive. It now seems better, but still not perfect.

I did do a full service on the ignition distributor about 2000 miles ago (and it felt awesome) but now the car has developed this symptom. Is it time for a new cap and rotor? Why would I only see half the rotor nose black/making apparent contact (literally one half of it looked perfectly clean almost).
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Old 03-24-2012, 06:54 AM
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Place a DVM on that rotor if the OHMS read over 1K, then you must swap it, cap are usually changed as well since resistance would have built up on that component as well.

Yeah, I agree brother that #4 plug is a love hate relationship, hate to remove it but love the re-freshed feel of new plugs Just do it. I bet the Gaps are crazy out of wack.

Wires on the other hand if still in good condition, no need to change.

Jim
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Old 03-24-2012, 08:03 AM
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