intermittent miss
Got a miss going on. It's intermittent. When the miss occurs, my wb reads full lean. I'd normally think secondary ignition, however when this miss occurs, the tach will drop ~500 rpm for an instant concurrently with the miss. It typically occurs while cruising between indicated 3k-3.4k rpm (but that may be because that's where I cruise at around town). But once I noticed it happening while decelerating in gear with my foot off the gas.
What would cause an ignition miss AND a simultaneous drop in RPM reading on the tach? CAS related? I do have a butt connection where the MSD box used to intercept the signal. I have extra plugs & wires. Could throw them in to see what happens, but I'm not betting on secondary ignition because of the tach phenomenon. |
Originally Posted by Ben
(Post 118437)
Got a miss going on. It's intermittent. When the miss occurs, my wb reads full lean. I'd normally think secondary ignition, however when this miss occurs, the tach will drop ~500 rpm for an instant concurrently with the miss. It typically occurs while cruising between indicated 3k-3.4k rpm (but that may be because that's where I cruise at around town). But once I noticed it happening while decelerating in gear with my foot off the gas.
What would cause an ignition miss AND a simultaneous drop in RPM reading on the tach? CAS related? I do have a butt connection where the MSD box used to intercept the signal. I have extra plugs & wires. Could throw them in to see what happens, but I'm not betting on secondary ignition because of the tach phenomenon. Is it rare, or somewhat consistent? |
It started as occasional, but seems to be getting more frequent. I see these little spikes of 0 injector activity in my datalog. I assume it's related.
http://img260.imageshack.us/img260/2840/missak3.png |
My money is on bad earths
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It's the factory harness so that normally shouldn't be a problem... though I think the grounds were vampire tapped for the wideband which can damage them.
Ben-- email me your full datalogs so I can take a closer look. |
I second that, either a poor ground or poor power
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1 Attachment(s)
datalog for anyone else interested.
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problem seems to be cured by swapping in a different ignitor.
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i had my money on ignitor as well it sends out RPM signal maybe your dwell time is cooking it slowly and then it starts to miss. :dunno: just a theory
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Originally Posted by Ben
(Post 119809)
problem seems to be cured by swapping in a different ignitor.
Think I'll try swopping the coils for a spare set I have and see what happens. |
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