CX500 Turbo RPM wrong

[eestrine]

With the settings you suggested, I get no spark at all on either plug. Tried Crank input on VR1 and Cam input on VR2, no luck. Switched them, same results.

[eestrine]

Al, these are the settings I have now

Trigger Wheel Teeth -- 9
Missing Teeth -- 0
Skip Teeth -- 9
Delay Teeth -- 1

M-o Wheel w/Falling Crank Sync
Offset 0.0

Ive tried several dozen combinations of wiring and dual spark options and get no spark and no RPM.

What do I do????

Frustrated
Elliott

[grippo]

I'm sorry I told you wrong - the one you want is "Falling Cam Sync with Tach or Wheel". The processor will know you have M- 0 because missing tooth will be 0. It is spelled out M- 0 for the crank synch, because you can't have M-1 with a crank synch, they would be redundant. But if you have a cam synch then you have to use "Falling Cam Sync with Tach or Wheel". Everything else remains the same.

When you try this check that you are getting solid rpm (no jumps to 0) and the rpm is correct. If it isn't, then post your msq and I will test it. Don't worry about the spark output, that is easy if you have solid synch. You will need to set the Offset Ouput#2 angle for this. (It isn't set with dual tach because the offset between sensors takes care of that, but it doesn't with the present case.)

[eestrine]

Al, changed the setting as you suggested and still no spark. I did get spark when I changed the setting to single cam sensor, but then it went away and cant repeat. Attached is the msq file.

Elliott

[grippo]

I tried your msq exactly as it was and it worked fine on the bench with a simulated 9 tooth wheel and a second cam pulse signal. Rock steady 600 rpm, one spark output right after cam pulse and then halfway between cam pulses on the second output. I also changed trigger offset to -27.5 because this input is supposed to be negative, but I got spark either way, but keep it negative - if necessary increase delay teeth. I also got spark whether I used trigger rise or calculated.

So I really don't think your problem is in the configuration. It is either in your tach input or in your ignition output electronics. That is why I asked you whether you got steady rpm during cranking. If you didn't then you can't expect spark, because the ECU is not, by design, going to spark unless it is sure where the engine position is. So do a short datalog and look at whether the rpm keeps spiking to 0, or stays at 0, and look at the trigger+/- column - does it count up or down or stay 0 ? If you disconnect the injectors, do you get good rpm ? (That would indicate there is too much jitter in the engine motion during cranking due to the 2 cylinders and the combustion.)

If the rpm is fine then crank without injectors and check the spark with a timing light or test light or just shorting the cable to near ground and see if it is firing. If it is, then, as long as the spark is strong, you can get the timing with a timing light and adjust trigger offset til it is right.

[eestrine]

Hi Al, glad to hear the msq is ok. We have no rpm. Exploring the setup we have on the crank wheel to see if the vr sensors are putting out enough signal to trigger the software. Is there a lower limit on the output of the sensor that the microsquirt will recognize. By the way I tried a different microsquirt box and got the same results.

Elliott

[grippo]

Yes there is a limit but I don't know what it is, but I don't think we have ever had a problem with this as long as the gap between wheel and sensor was not too large. The manual tells you what is a reasonable gap. If yours is much larger, try reducing it a bit. Your setup is a bit difficult because you have no missing tooth, so you won't see anything whatsoever if the cam doesn't occur. You can try loading the tachref program to see whether the processor is seeing both signals, or you can scope it on the board, by looking at the schematic for the VR sensors. Each circuit will have a pin which goes direct to the processor, and you want to scope this to see what the ECU sees.

[eestrine]

Hi Al, we put a scope on the crank and cam VR signals. The crank sensor on the 9 tooth flywheel showed a beautiful clean wave that was 12 volts peak to peak. The cam sensor wave was 1.4 volts peak to peak and did not seem to be triggering as you mentioned. We did a LOT of experimenting. In the Single Crank Wheel mode we got a very clean 500 rpm and SPARK. But in the Falling signal with cam ... mode no rpm and no spark. So we are looking into ways to hop up the output of the cam sensor.

Elliott

[24c]

....So we are looking into ways to hop up the output of the cam sensor.

Decreasing the clearance did it for me ( I skimmed my rocker box cover at the cam sensor fixing to lower it), but are you using a cased MicroSquirt or Module?

[eestrine]

Al, since the cam VR sensor is putting out such a low signal, we are considering replacing it with a Hall sensor. Hall Sensor to OPTIN+/- and crank VR sensor to VRin2. Do you forsee any problems with this solution?

Elliott