Erratic low RPM timing.
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Joined: Dec 2007
Posts: 7,987
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From: Boise, Idaho
Erratic low RPM timing.
Hi all,
I'm having an odd issue with my timing.
I've noticed this the last few times I've tried to check my timing with a light and am not sure what's causing it. At first I thought maybe it was my new timing light, but it doesn't have this problem on other vehicles, so I'm pretty sure it's my engine.
When my engine is idling and I put the timing light on the balancer, the timing mark disappears and reappears. Meaning, for a moment, it'll be sitting right on the 10° line (or wherever I have it set), and then it'll just disappear (like it's off the chart), then come back, then disappear, etc. etc. I have to really pay attention to see when it's on the mark to see what my engine timing is set to.
The faster the RPMs go, the more it steadies out and points to right where the timing is.
Any idea what's causing this? I'm having a real issue with an off-the-line stumble, plus a pop in the exhaust, so it's not like there aren't any symptoms. I just don't know what would cause the timing to dance around.
I'm having an odd issue with my timing.
I've noticed this the last few times I've tried to check my timing with a light and am not sure what's causing it. At first I thought maybe it was my new timing light, but it doesn't have this problem on other vehicles, so I'm pretty sure it's my engine.
When my engine is idling and I put the timing light on the balancer, the timing mark disappears and reappears. Meaning, for a moment, it'll be sitting right on the 10° line (or wherever I have it set), and then it'll just disappear (like it's off the chart), then come back, then disappear, etc. etc. I have to really pay attention to see when it's on the mark to see what my engine timing is set to.
The faster the RPMs go, the more it steadies out and points to right where the timing is.
Any idea what's causing this? I'm having a real issue with an off-the-line stumble, plus a pop in the exhaust, so it's not like there aren't any symptoms. I just don't know what would cause the timing to dance around.
Elder User
Joined: Dec 2003
Posts: 660
Likes: 3
From: Northern California
Hi all,
I'm having an odd issue with my timing.
I've noticed this the last few times I've tried to check my timing with a light and am not sure what's causing it. At first I thought maybe it was my new timing light, but it doesn't have this problem on other vehicles, so I'm pretty sure it's my engine.
When my engine is idling and I put the timing light on the balancer, the timing mark disappears and reappears. Meaning, for a moment, it'll be sitting right on the 10° line (or wherever I have it set), and then it'll just disappear (like it's off the chart), then come back, then disappear, etc. etc. I have to really pay attention to see when it's on the mark to see what my engine timing is set to.
The faster the RPMs go, the more it steadies out and points to right where the timing is.
Any idea what's causing this? I'm having a real issue with an off-the-line stumble, plus a pop in the exhaust, so it's not like there aren't any symptoms. I just don't know what would cause the timing to dance around.
I'm having an odd issue with my timing.
I've noticed this the last few times I've tried to check my timing with a light and am not sure what's causing it. At first I thought maybe it was my new timing light, but it doesn't have this problem on other vehicles, so I'm pretty sure it's my engine.
When my engine is idling and I put the timing light on the balancer, the timing mark disappears and reappears. Meaning, for a moment, it'll be sitting right on the 10° line (or wherever I have it set), and then it'll just disappear (like it's off the chart), then come back, then disappear, etc. etc. I have to really pay attention to see when it's on the mark to see what my engine timing is set to.
The faster the RPMs go, the more it steadies out and points to right where the timing is.
Any idea what's causing this? I'm having a real issue with an off-the-line stumble, plus a pop in the exhaust, so it's not like there aren't any symptoms. I just don't know what would cause the timing to dance around.
Sounds like you're dropping a "block ground" intermittantly.
Bob
Tuned
Joined: Jun 2003
Posts: 307
Likes: 1
From: South Florida
Your centrifugal advance may be fluttering a bit with too light of springs or idle varying enough to kick it in and out a bit.
I assume the vacuum advance isn't connected when you are checking the timing, so varying vacuum won't play a big role.
The only other thing could be a severely worn dist gear or the cam slapping back and forth. You would have to pull out the dist and bump the engine to check for cam movement.
I assume the vacuum advance isn't connected when you are checking the timing, so varying vacuum won't play a big role.
The only other thing could be a severely worn dist gear or the cam slapping back and forth. You would have to pull out the dist and bump the engine to check for cam movement.
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