Long sync time on crank sensor

Discuss which Sensors work best with these ECUs and share how you are using inputs and outputs
Rob Stevens
Posts: 1137
Joined: Thu Jul 28, 2011 4:10 am
ECU Model: S100 Pro
Distributor: None-Coil On Plug :)

Re: Long sync time on crank sensor

Post by Rob Stevens »

The screen dump shows just 133 rpm max, that is very slow, is there a drop in hall crank sensor available?
Alex DTA
Posts: 1489
Joined: Fri Feb 28, 2014 1:03 pm
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79

Re: Long sync time on crank sensor

Post by Alex DTA »

stevieturbo wrote:@Alex

What on the scope trace suggests polarity may be incorrect ? I know on an actual oscilloscope the trace would show this, but on the DTA scope, what are the visuals on it ?
The gap doesn't display correctly, there are two pulses instead of 1.
This is a 36-1 with the wires reversed:
Image

This is a 36-1 with the wires reversed:
Image

As you can see, identical crank trigger set ups, but location of gap affects what the ECU sees.
To be fair, the first one is quite common, the second one quite rare that nothing is seen at all.
aleksanderk
Posts: 52
Joined: Fri Feb 01, 2019 4:36 pm
ECU Model: S80 Pro
Firmware Version: 6500

Re: Long sync time on crank sensor

Post by aleksanderk »

The trigger is on the flywheel, and looks like this:
Image

The sensor sits at 12-o-clock on the back of the engine as you can baely see in this photo:
Image

I can see why you mention that the signal is inverted because the flywheel have valleys instead of peaks for the sensor ti trigger on.
I will try to get 2 scopes for you today.

Thanks for all the help, and good discussions this far :D
aleksanderk
Posts: 52
Joined: Fri Feb 01, 2019 4:36 pm
ECU Model: S80 Pro
Firmware Version: 6500

Re: Long sync time on crank sensor

Post by aleksanderk »

Okay, so I finally got around to get some new scope images. Reducing tooth factor to 1500 dramatically reduced cranking time! Tried 1800 and 1600, and felt i was the shortest at 1500.

Cold crank with tooth factor set to 2000:
Image

Cold crank with tooth factor set to 1800:
Image

Hot crank whith tooth factor set to 1600:
Image

Hot crank when tooth factor set to 1500:
Image

I forgot to save an image of hot crank@2000/1800
Alex DTA
Posts: 1489
Joined: Fri Feb 28, 2014 1:03 pm
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79

Re: Long sync time on crank sensor

Post by Alex DTA »

Swap the pins 1 and 2 on the sensor, and try again.
You have holes rather than teeth, so everything is reversed.
aleksanderk
Posts: 52
Joined: Fri Feb 01, 2019 4:36 pm
ECU Model: S80 Pro
Firmware Version: 6500

Re: Long sync time on crank sensor

Post by aleksanderk »

Alex DTA wrote:Swap the pins 1 and 2 on the sensor, and try again.
You have holes rather than teeth, so everything is reversed.
I will try that. Should I set the tooth factor to 2000 then?
aleksanderk
Posts: 52
Joined: Fri Feb 01, 2019 4:36 pm
ECU Model: S80 Pro
Firmware Version: 6500

Re: Long sync time on crank sensor

Post by aleksanderk »

I swapped the pins and set the tooth factor back to 2000. Starts as good as it did before on 1500 :D

Gap tooth factor 2000 after reversing pin 1 and 2:
Image

Gap tooth factor 1500 after reversing pin 1 and 2:
Image

Just for reference, I uploaded another video on a hot start now. I still feel like it should be a little faster to start, but it's an old starter, so it might not turn the engine fast enough. And just having crank and no cam trigger might also add to a bit longer start?
When it gets sync it fires right up!
Video: https://www.youtube.com/watch?v=AGLNMyOhglw

And yes, I need to connect the tachometer. Just need to get a 1Kohm resistor first.
stevieturbo
Posts: 3271
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: Long sync time on crank sensor

Post by stevieturbo »

Bare in mind, slow to start, and slow to sync are two very different things.

Once sync'd, it should be able to start very quickly. If not sync'd...it wont start.

And polarity of a VR sensor must be correct, or ignition timing will be all over the place as revs change.
aleksanderk
Posts: 52
Joined: Fri Feb 01, 2019 4:36 pm
ECU Model: S80 Pro
Firmware Version: 6500

Re: Long sync time on crank sensor

Post by aleksanderk »

stevieturbo wrote:Bare in mind, slow to start, and slow to sync are two very different things.

Once sync'd, it should be able to start very quickly. If not sync'd...it wont start.

And polarity of a VR sensor must be correct, or ignition timing will be all over the place as revs change.
I know. It fires right up when it gets sync. Takes less than .5sec.
As Alex said earlier; The wiring was correct, but I don't know if he ment that is was correct for a trigger wheel with teeth or with holes. Or if the wiring matter for that reason.
It got better when reversing the wiring.

About the timing, that is something I need to take a look at. Timing seemed stable and good before.

What other things will help the ECU get sync faster?
Sorry for all my questions :oops: When i get to have a discussion with someone who knows what they are doing, I just want to absorb as much knowledge as possible :lol:
Alex DTA
Posts: 1489
Joined: Fri Feb 28, 2014 1:03 pm
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79

Re: Long sync time on crank sensor

Post by Alex DTA »

aleksanderk wrote:I swapped the pins and set the tooth factor back to 2000. Starts as good as it did before on 1500 :D

Gap tooth factor 2000 after reversing pin 1 and 2:
Image

Gap tooth factor 1500 after reversing pin 1 and 2:
Image

Just for reference, I uploaded another video on a hot start now. I still feel like it should be a little faster to start, but it's an old starter, so it might not turn the engine fast enough. And just having crank and no cam trigger might also add to a bit longer start?
When it gets sync it fires right up!
Video: https://www.youtube.com/watch?v=AGLNMyOhglw

And yes, I need to connect the tachometer. Just need to get a 1Kohm resistor first.
Those traces are now perfect.
Note - the gap tooth fact won't affect the trace. The gap tooth factor is set depending on what is in the trace.
You should get immediate sync with that trace.

If I've understood correctly, your sync issues are now sorted?
Post Reply