Timing jitter, or is it a misfire?
Thread Starter
Joined: Jun 2008
Posts: 8,376
Likes: 28
From: Chino Hills, CA
Yep.
I never did get rid of it, and doesn't seem to interfere with the engine running well - it's slight when the engine is warm.
It makes for some interesting subsonics when the car is warming up on the choke (travels right thru the walls of the house) but otherwise doesn't seem to have any impact.
My current working theory is that the distributor gears have enough mecahincal wear on them that they're allowing a bit of slap at low RPMs, which wobbles the timing slightly. I can find no spec anywhere for dizzy gear wear limits, though.
I never did get rid of it, and doesn't seem to interfere with the engine running well - it's slight when the engine is warm.
It makes for some interesting subsonics when the car is warming up on the choke (travels right thru the walls of the house) but otherwise doesn't seem to have any impact.
My current working theory is that the distributor gears have enough mecahincal wear on them that they're allowing a bit of slap at low RPMs, which wobbles the timing slightly. I can find no spec anywhere for dizzy gear wear limits, though.
Joined: Mar 2001
Posts: 31,837
Likes: 3,234
From: https://www2.mazda.com/en/100th/
Also a trick you can do is to unhook or temporarily plug your smog pump so it’s not cooling your cats. .Then retard your IGN timing 5-10*. This will add a ton of heat to the exhaust. Drive it like a baby to the test. And once passed make sure to change settings back to normal. My car passed years ago by doing this.
Joined: Mar 2001
Posts: 31,837
Likes: 3,234
From: https://www2.mazda.com/en/100th/
Yep.
I never did get rid of it, and doesn't seem to interfere with the engine running well - it's slight when the engine is warm.
It makes for some interesting subsonics when the car is warming up on the choke (travels right thru the walls of the house) but otherwise doesn't seem to have any impact.
My current working theory is that the distributor gears have enough mecahincal wear on them that they're allowing a bit of slap at low RPMs, which wobbles the timing slightly. I can find no spec anywhere for dizzy gear wear limits, though.
I never did get rid of it, and doesn't seem to interfere with the engine running well - it's slight when the engine is warm.
It makes for some interesting subsonics when the car is warming up on the choke (travels right thru the walls of the house) but otherwise doesn't seem to have any impact.
My current working theory is that the distributor gears have enough mecahincal wear on them that they're allowing a bit of slap at low RPMs, which wobbles the timing slightly. I can find no spec anywhere for dizzy gear wear limits, though.
I've seen jitter. I think it was caused by the pickup itself. It's not the reluctor because I didn't see it occur on the other pickup, and it's not the ignitor because I swapped them and still saw jitter on just that one pickup.
Maybe the pickup's self-centering effect was not working very well? Maybe it was seeing the edges of the reluctor differently ie reading the leading edge of one while reading the trailing edge of the next, and so on.
Maybe the pickup's self-centering effect was not working very well? Maybe it was seeing the edges of the reluctor differently ie reading the leading edge of one while reading the trailing edge of the next, and so on.
Lives on the Forum
Joined: Jun 2004
Posts: 11,359
Likes: 14
From: Grand Rapids Michigan
Mine does exactly the same thing. Never found a way around it, or any issues with my ignition system.
btw, the stock pulley has a circumference of 360 millimeters, so one degree would be one millimeter.
Glad to hear that you passed okay...
btw, the stock pulley has a circumference of 360 millimeters, so one degree would be one millimeter.
Glad to hear that you passed okay...
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