Elect Ign Distributor Output LOW?
- Thread starter 6pak
- Start date
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pishta
I know I'm right....
Reading this again makes me wonder about my other ignition, Mazda B2000 w/electronic distributor. Kinda the same issue: I got a wandering vacuum guage from 19-23, it just lazily goes up and down while the 4 banger idles like a diesel. I shot carb cleaner everywhere and no vacuum leaks, RPM is not stable either. 3 different carbs little change. I can plug the PCV and get another 2 inches vacuum but it still wanders. All valves are lapped in, double valve springs and blueprinted spring height as well as new head and intake gasket. Pretty steady exhaust flow with a random miss about 3 every 5 seconds? I replaced the Ignition control module (black plastic semi-circle with 4 leads off it) but never replaced the "reluctor" that has 3 (?) pickups off it....? Why 3? could these be out of spec gap wise? Never even checked them as they dont seem to be adjustable. Even threw a Hi-6R ignition on it with absolutely no change. timing light off #1 is steady.
KitCarlson
Well-Known Member
I think in trouble shooting, it will be necessary to separate mechanical issues from electrical issues. It is hard, because variable reluctance sensing is not good for position reference, with trigger variations due to angular velocity, gap, remnant magitizm, and other noise and analog thresholds.
The reluctor shown has 3 poles, I assume trigger coil has 4. It seems if run-out of rotor shaft is such that gap is greater, then there could be slight timing retard on that associated cylinder. Simple tests with brass or plastic feeler gauges checking for equal gaps may be helpful. Also check if rotor shaft has slop. Direct gear driven distributors often wear bushings elongated, and with points would result in timing variation for one cylinder.
If shaft and gaps good, try probing reluctor teeth with a toy compass looking for magnetization and polarity. Use demagnitizer like for audio tape head.
In doing research I found B2000 ignition parts varied by model year. Later they went to 4 pole reluctors. I wonder if it would be possible to change to newer model complete distributor?
Using a good ignition scope with ability to measure per cylinder timing variations, or pulley timing wheel and moving timing light trigger on cylinder plugs, may help too.
The reluctor shown has 3 poles, I assume trigger coil has 4. It seems if run-out of rotor shaft is such that gap is greater, then there could be slight timing retard on that associated cylinder. Simple tests with brass or plastic feeler gauges checking for equal gaps may be helpful. Also check if rotor shaft has slop. Direct gear driven distributors often wear bushings elongated, and with points would result in timing variation for one cylinder.
If shaft and gaps good, try probing reluctor teeth with a toy compass looking for magnetization and polarity. Use demagnitizer like for audio tape head.
In doing research I found B2000 ignition parts varied by model year. Later they went to 4 pole reluctors. I wonder if it would be possible to change to newer model complete distributor?
Using a good ignition scope with ability to measure per cylinder timing variations, or pulley timing wheel and moving timing light trigger on cylinder plugs, may help too.
KitCarlson
Well-Known Member
I'm good. I 3D print, and restore early sewing machines. A down size from working in cars. Not sure can still do electronics. I'm a bit scared to find i can't.
pishta
I know I'm right....
KitCarlson I believe I found my issue after all, and it had nothing to do with ignition! The damn intake gasket was bad (new!) as it was leaking out the bottom where I could not shoot carb cleaner into to alter the idle quaility. Once I got that replaced the idle quality perked right up and I was able to get a steady idle with just a little wiggle of the vacuum gauge. I them took a .003 feeler gauge and proceeded to get it between every valve under the valve cover while at a slow idle and found 2 were out of spec fat and 2 were actually too tight! After I got all those ironed out, my idle is smooth once again, the vacuum gauge is nailed at 20" and I can get the carb to idle with only 1/4 turn of the curb idle screw. I suspect this gasket was vintage 1975 as the box was very dry and the gasket felt like a piece of brittle parchment? I cut one out of an old album cover and its working great. About the same material as the carb gasket is made of.
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