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Post by adamnphx on Mar 18, 2015 0:23:20 GMT -5
Mrriggs i am finally getting around to reassembling my motor with a rephased crank. I went single fire with 2 pickups, hei modules and coils. I was curious if you think it would be beneficial to leave both reluctor teeth and keep the waste spark or grind one more off so just a single tooth remains. Thanks for sharing your knowledge and any input you may have.
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Post by mrriggs on Mar 18, 2015 11:16:17 GMT -5
If you are setup for single fire then there is no benefit to waste spark. Grind it down to a single tooth.
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Post by farmrjohn on May 3, 2015 21:18:07 GMT -5
mrriggs-thanks for your help. I have the Toyoto/GM HEI system installed and it works like a champ. I had to swap the pickup leads though as the white lead from the Toyota pickup to the gray points lead in the harness produced that erratic timing you mentioned. When I swapped the leads and she fired right up. I started with the reluctor and advance mechanism set at the idle position, and adjusted the points plate to yield full advance as the RPMs increased. It runs great, thanks again.
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Post by kopcicle on May 24, 2015 21:49:32 GMT -5
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Post by farmrjohn on Aug 31, 2015 22:04:11 GMT -5
mrriggs-I have had what is a transient problem with what until now has been an excellent mod. The other day coming up to a roundabout, as the rpm dropped below 3000 the ignition cut out and the engine quit. It started right back up alongside the road, but if the rpm increased slowly above 2000 rpm the engine would quit. If I quickly reved it past 3000 rpm it would run fine until it dropped below 3000, when it would quit again. Thinking it might be fuel related, I would use only one carb to increase the rpm, and it would quit passing 2000. Suspecting ignition, I checked the reluctor/sensor continuity and output, both good, and if the sensor was shorted to ground, check also good. I replaced the HEI module, and had the same results with the new one. Thinking it might be fuel after all, even though it ran fine past 3000 rpm, pulled and cleaned the carbs. Carbs back on and same symptoms. I put a timing light on, and the timing was good, and when the mechanical advance would start advancing with the increasing rpm, the engine would die along with the spark, until the engine stopped turning, when the light would light once as it stopped. This leads me to think the coil was charging, and not getting a signal to "fire". I put the original HEI module back in, and everything seems back to normal.
I've read on a Kawasaki forum: "Because of the positive DC feedback, the DC voltage on W can grow higher and higher if left unchecked, as long as there is a significant signal from the reluctor. Without a signal, the feedback loop decays and W ends up back at 1.2 volts. The limit to how high the voltage on W can get seems to be about 6 or 7 volts, but may possibly be higher. If the voltage gets too high (and the reluctor signal can't go negative enough), the dwell may eventually become infinite. In that case, no more sparks will occur, the engine will stumble until the capacitor drains low enough for the input signal to once again cross below the turn-off threshold allowing sparks to resume. The engine may backfire and resume running at this point, or may stall completely."
Could this be what's happening, and would the circuit you added to prevent the false firing prevent it? Or could it just be that there was a bad pigtail connection on the W terminal?
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Post by mrriggs on Sept 18, 2015 13:45:22 GMT -5
If it was a W-pin voltage issue then it would be odd for it to start all of a sudden after working properly. A quick way to test it would be to unplug the wire from the W-pin, hook it to the positive side of a 1.5 volt battery (AA,AAA,C...), hook the negative side of the battery to ground. This will apply a constant 1.5 volt bias to the pickup, the same as the external bias circuit I built. If it solves your issues then you can built the external circuit to make it permanent.
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Post by farmrjohn on Sept 19, 2015 18:52:34 GMT -5
If it was a W-pin voltage issue then it would be odd for it to start all of a sudden after working properly. A quick way to test it would be to unplug the wire from the W-pin, hook it to the positive side of a 1.5 volt battery (AA,AAA,C...), hook the negative side of the battery to ground. This will apply a constant 1.5 volt bias to the pickup, the same as the external bias circuit I built. If it solves your issues then you can built the external circuit to make it permanent. mrriggs, thanks again. I'm assuming that's the circuit you describe on page 10 rather than the one on page 9. Using that circuit would leave the W pin on the HEI module open, with no wire attached, correct? |
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Post by mrriggs on Sept 27, 2015 17:42:43 GMT -5
I'm assuming that's the circuit you describe on page 10 rather than the one on page 9. Using that circuit would leave the W pin on the HEI module open, with no wire attached, correct? Yes, nothing is hooked to the W-pin. |
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