Need Help with 2 cylinder CX500 timing

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eestrine
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Joined: Tue Oct 27, 2009 8:20 pm

Re: Need Help with 2 cylinder CX500 timing

Post by eestrine »

Grippo, there is only one trigger bar on the flywheel. It's about one inch long. I will try your suggestions and get back.

Thanks
Elliott
eestrine
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Posts: 38
Joined: Tue Oct 27, 2009 8:20 pm

Re: Need Help with 2 cylinder CX500 timing

Post by eestrine »

I did as you recommended and set all the offsets to 0.0 also the trigger wizard said 0.0. The engine ran, timing was at 27.5 deg, but the RPM was still wrong. Delta varying between 5ms and 15 ms. Also noted with the timing light that sometime we would see marks for both cylinders at the same time.

So I decided to go back to square 1 and look at timing for each cylinder separately, with plugs out and no fuel injection. Disconnected the VRin2 sensor and spark was ok on left cylinder, timing OK. Reconnected VRin2 and disconnected VRin1. No spark on either plug. With both connected spark on both plugs. It appears that the channels are not independent as stated in the manual. If no VRin1, VRin2 does NOT fire the Right Cylinder.

Thanks
Elliott
grippo
MegaSquirt Guru
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Joined: Mon Feb 16, 2004 6:55 pm

Re: Need Help with 2 cylinder CX500 timing

Post by grippo »

You need to stop with the first test. The rpm is wrong because the deltaT is wrong. When you went to just 1 VR input connected that messed up the code logic because you specified dual tach, but you only have one input. It expects a pulse on VR1 followed by a pulse on VR2, etc, so yeah I can see how that is messing everything up. But that is as it should be. The problem as I see it goes back to the first test with both connected. Why is the deltat jumping from 5 to 15 when you have 2 sensors, both seeing the same tooth, so the deltaTs should be the same unless one of the sensors is screwed up or won't work with the second VR circuit, which is a bit different from the first, because people generally put a cam mounted Hall sensor on this.
800vtwin
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Re: Need Help with 2 cylinder CX500 timing

Post by 800vtwin »

Just a thought - after the msq is straightened out as per grippo.

Try seperating the common vr grounds. Install a diode on each one. (1n 4000 series - stripe facing ecm to block the return ac voltage.) Keeping noise out of the opposite vr.
abecedarian
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Joined: Sun Jun 03, 2012 7:14 am

Re: Need Help with 2 cylinder CX500 timing

Post by abecedarian »

I'm wondering if any progress has been made on this as I'm contemplating the same thing.
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