Magnetic crank trigger?

[art leong]

I run a magnetic crank trigger (not flying magnets). I use a 20 tooth steel trigger wheel (adjustable). And a 05 Honda 2 wire cam sensor (reluctor) for a pickup. My ECU reads the falling part of the signal. So I've been lining up a tooth just past the pickup magnet (about 1/4" in the center of the pickup which is .700 round). When number 1 is at TDC firing. But I have no way of checking the accuracy of my settings. I know how to set the cam sensor timing. By use a function to lock the advance at 20 degrees and dial 20 degrees into my timing light. If the timing marks don't line up I change the light till they do then put in the offset.
But I don't have this function for the crank timing.
If I could get a signal from the crank pickup to my timing light. I could get it right.
Anyone know how I could use the pickup to trigger a timing light? This way I could see exactly what position the tooth is in relation to the pickup.

[buzzinhalfdozen]

Art, I'm having trouble understanding exactly what you're trying to determine. I'm not aware of a way to trigger your timing light using the crank sensor which I'm assuming is a VR type,it does produce a sine wave but fail to see how to use that to trigger your light.You state that you're using your timing light to check CAM sensor timing? In what way are you checking this, I'm unfamiliar with your system, however most EMS units only use the cam sensor pulse to determine TDC compression cycle for sequential timing and fuel events. Does your cam sync have more than 1 trigger event per revolution?Actually I think the "offset" you're referring to would be for the crank sensor, my system uses this to trim out any errors between what the EMS "calculated"timing is and what the timing light is showing. As I stated I'm not familiar with your system, but most simply use the "trigger" tooth on the crank sensor...knowing it occurs X number of degrees before TDC then calculates timing events based off that, while utilizing the cam sync to determine which "cycle" it's on. Sorry for the long post just trying to determine exactly what you're tring to determine. Joe Also do you use a "missing tooth" trigger wheel for the crank sensor?

[Greg Reimer 7376]

Art- I think I understand your description of your system, a few things caught my attention. A crank position sensor or cam position sensor, (reluctor) creates a sine wave that is very low amperage. It is discernable by an ECU, but probably not much else, since the signal is probably in small fractions of an amp. Not enough to run an auxillary circuit like the pick up of a timing light. The ECU reading the falling part of the signal( probably the point where the signal has just peaked and is now falling downhill after the trigger wheel tooth last excited the sensor has little to do with a timing light event. The timing lights I've always used were run off the spark plug wire as the plug fires. That's all thats relevant here. It doesn't matter to your piston where the ECU reads the sensor signal. The only thing mattering in the cylinder is how many degrees BTDC the spark occurs.Cam sync has little or nothing to do with spark timing,since its based off of crank position anyway.

[buzzinhalfdozen]

Art, after thinking on this a bit, I believe I know what you're trying to do. You're trying to correct the error between what the EMS says the timing is and what you're seeing with your timing light? If this is correct all you need do is watch what the ECU is calculating as the timing...check with light and set the offset to correct the error. Assuming this is what you're after, remember which tooth it's actually triggering off of is more or less irrellevant as long as the calculated and actual timing numbers match. Joe BTW 1/4 inch pick up seems pretty wide how far are your teeth spaced apart? I'll assume much more than 1/4 inch as I've been told the pick up needs to be at least minimum 1/2 the width of the tooth spacing.

[art leong]

Here are the instructions on how to set base timing. I'm starting to think I was told wrong by the guy that installed the unit.
He told me that I was setting the cam position sensor timing, and that it was telling the ecu that when it got the signal the next signal from the crank was tdc firing.
With the old software they put a timing light on the crank trigger to set it.
When I advance or retard the intake cam (where the cps is) I have to reset the offset, Even though I didn't touch the crank sensor or wheel

Here is a copy of the instructions Thanks

Once the correct Triggering Mode has been selected and Triggers 1 and 2 configured, the trigger timing must be calibrated by checking the ignition timing using a timing light. Doing this tells the ECU where the trigger signals occur in relation to engine position.







To Calibrate Triggers



1. In the Triggers->Calibrate menu, click the Set Base Timing button . This will open the Set Base Timing window.



2. While the Set Base Timing window is open, timing is locked to a constant value.



3. Enter the ignition timing value that you want to see with the timing light in the Lock Ignition Timing To: value. This value will depend on the location of available timing marks. 0 (TDC) and 10 deg BTDC are the most common values.




4. This step depends on the instructions shown in the Set Base Timing window.


· Adjust Offset until Ignition Timing matches the number above. Alter the number in the Offset setting until the timing light shows the number entered in the Lock Ignition Timing To: setting. Increase this number to advance ignition timing. Decrease this number to retard ignition timing.




· Adjust CAS until timing matches the number above. Mechanically rotate the position of the crank angle sensor (or distributor if it contains the CAS) until the timing light shows the number entered in the Lock Ignition Timing To: setting.




5. Click Done to keep the new Trigger Calibration settings. Otherwise click Cancel to restore the previous values.



6. Perform a STORE to permanently store the new trigger calibration setting to the ECU.

This explains trigger offset.
The Trigger Offset is used to calibrate the trigger timing so that the ECU can calculate the correct engine position at any time.



Trigger Offset is defined as the offset between TDC (between compression and power stroke) on cylinder number 1 and the first trigger event on Trigger 1 that occurs after the sync (Trigger 2). Therefore if the sync occurs and the next tooth on Trigger 1 passes the sensor at exactly TDC no. 1 then the required trigger offset will be 0. If this is not the case (and it typically will not be) then a non-zero Trigger offset will be required.


Although the trigger timing affects both fuel and ignition, it is easiest to calibrate the trigger timing by getting the ECU to try and deliver the ignition timing at a fixed angle (e.g 10deg BTDC) and checking that the ignition is actually occurring at this point using a timing light. This procedure is described under Trigger Calibration.



Note: As off Vi-PEC Tuning Software V4.4.0 and later this setting can only be adjusted in the Set Base Timing Window

[buzzinhalfdozen]

Seems somewhat confusing to me. I understand setting the offset to correct for "requested" timing versus actual timing checked with a light, however the next step of moving the crank sensor baffles me, why would that need to be moved you just corrected any errors with the offset function! Joe BTW how many triggers does your cam sync have? OK after reading the last part of your last post I see what they're doing, the offset they're referring to is between the crank and cam sensors. Then you physically move the crank sensor for Ign. timing error sorta like changing the timing on an MSD crank trigger set up. I was confused as my system uses the offset to correct Ign. timing event errors. Based on what you're saying I can assume your crank trigger wheel does not employ a "missing" tooth design?

[art leong]

My plan is to use the set base timing function. And adjust the trigger wheel to match what offset is in the ecu now. It was running good.
But when I put the timing light set at zero. On my balancer/trigger it shows the tooth past the center of the pickup. My tooth to tooth distance is about 1 inch we take a 60-1 wheel and grind 2/3 of the teeth off this makes it 20 teeth evenly spaced.
We originally tried using it as it came but it would break up past 4000 rpms. Proving what you were saying about the size of the magnet.
I'm the type of guy that wants to know why it works. So if I have a problem it will be easier to figure out. Plus if I have to build it again I can duplicate it.

[buzzinhalfdozen]

OK Art, I'm seeing what you're dealing with. Without the missing teeth the only way the ECU can determine crank angle is to have a sync event just propior to the trigger event, is that correct? Seems like you should be able to calculate the offset shift based on how many degrees you change the cam shaft phasing divided by 2? Don't know why but I love this stuff as it can easily fry a mind as challenged as mine. Good luck and please let me know how you make out. Joe BTW, I believe what you're seeing as far as the point at which your timing light is showing the sensor as being in the middle, more or less instead of the edge of the tooth has more to do with "time" it takes time to trigger, then to fire the coil, then to trigger your light, at least that's how I see it, I wouldn't overly concern myself with that aspect.

[art leong]

Started it up today and manually adjusted the trigger wheel to match what the timing was when I took it apart.
Sounds alright idles fine.
Now if my tires can stay round. I'll be in the running at Concord.

[buzzinhalfdozen]

Glad to hear it Art. Didn't I read somewhere you had the crank hub come off? Hopefully you have that issue handled as well. Keep up the good work. Joe