Swapped VR Cam Sensor with Hall now will not start

[cksiver]

I tried posting this on Saturday, however, it never showed up on the Forum. My computer was acting strange so I assume that it did not post. If it did, please forgive the repeat.

I had my car running well with a VR cam sensor, but wanted a smaller sensor so I did a swap to a Hall Sensor. I used the same signal and ground wires for the hall sensor that I used for the VR. I did have to add a 12 volt power wire to power the hall sensor. I sourced the 12 volt supply from the power wire going to the megasquirt, which is what is indicated in the manual (on the wiring diagram) as the right place to get the power.

Also according to the manual dash pot, R52 and R56 were adjusted, with R52 getting 12 anticlockwise turns and R56 getting 12 anticlockwise turns followed by 6 clockwise turns. As for the jumpers, they were already in place given the Hall jumpers are the same as the VR settings.

Well I am sure you guessed by now, the car will not run. When I turn the key it fires off, but then dies right away. Is there something that I need to do that I missed? I do not think anything would have to be changed with the fuel settings because all of the air and fuel delivery systems remain the same.

As you will see in the logs, the cam and tack signals are strong. All the wiring of the rest of the system is per the megasquirt wiring diagram.

Any on suggestions on what to look for next will be greatly appreciated.

Regards,

Curtis

[billr]

What goes away as it cranks-fires-dies? Use a timing-light to watch spark, meter or 'noid light to watch injector pulses, and a mechanical gauge to watch fuel pressure. You could try "wasted-COP" to get the cam sensor out of the equation, but I think MS defaults to that anyway when you have a 36-1 crank wheel and the cam signal is bad. Easy to try, but probably won't make any difference.

[cksiver]

Bill,

Great suggestion.

I did the Waste-COP and it fired up and ran. I did not run it long because I have the doghouse currently off the engine (the engine is air cooled) to give more space to work/trouble shoot.

I will play with the timing light to see why the cam sync had to be taken out of the picture. Clearly I must not have it firing in the right place.

Thank you for the suggestion. It at least it starts so I can play to find the why.

Regards

Curtis

[billr]

Try changing the "second trigger" to "falling edge" or "poll level". With "poll level" I think you will have two "engine phase" choices there, too. Try both.

I think it is firing in "wasted COP", then going 360 deg. out once the cam signal is detected.

[cksiver]

Well, in an effort to bring closure to the discussion.

I finally had time to explore this issue. What I found was that the cam gear was off by two teeth. I made the adjustment and they car started up with no issue. It is now running strong on a Hall cam sensor.