RPM signal from ECU (syvecs)
Discussion
Hi all,
I've recently had a Syvecs S7 plus with Honda FN2 "plug and play" harness fitted and mapped on an Ariel Atom running a Honda K20, all supplied and fitted by an authorised dealer. Since the install, the rev counter has not worked properly, it's either dropping in/out or not registering at all. Also, a completely separate set of shift indicator lights have stopped working. Both of the rev counter and shift indicator lights both take an RPM feed from the Syvecs (pin A14). I have traced this wire back and cannot find any issue in continuity by measuring resistance on a multimeter. Before the Syvecs install, both the rev counter and shift indicator lights worked fine on the standard Hondata Honda ECU.
Does the Syvecs ECU output a "different" type of RPM signal compared to the Hondata Honda ECU? It is very strange that two INDEPENDENT systems that use the same RPM signal now do not work after the Syvecs ECU install. Even though I could not fault the existing RPM signal wire to the rev counter and shift lights, I ran a temporary new wire from the harness back to the rev counter and shift lights to bypass the existing RPM signal and thus definitely eliminate that from being the cause.
I would be very grateful for any help
I've recently had a Syvecs S7 plus with Honda FN2 "plug and play" harness fitted and mapped on an Ariel Atom running a Honda K20, all supplied and fitted by an authorised dealer. Since the install, the rev counter has not worked properly, it's either dropping in/out or not registering at all. Also, a completely separate set of shift indicator lights have stopped working. Both of the rev counter and shift indicator lights both take an RPM feed from the Syvecs (pin A14). I have traced this wire back and cannot find any issue in continuity by measuring resistance on a multimeter. Before the Syvecs install, both the rev counter and shift indicator lights worked fine on the standard Hondata Honda ECU.
Does the Syvecs ECU output a "different" type of RPM signal compared to the Hondata Honda ECU? It is very strange that two INDEPENDENT systems that use the same RPM signal now do not work after the Syvecs ECU install. Even though I could not fault the existing RPM signal wire to the rev counter and shift lights, I ran a temporary new wire from the harness back to the rev counter and shift lights to bypass the existing RPM signal and thus definitely eliminate that from being the cause.
I would be very grateful for any help
I don't know what the Honda outputs, but the Syvecs would just be a simple pull to ground.
TBH I'd be surprised if the Honda was any different....but clearly it isn't working,
Martin's pullup resistor would most likely be from the 12v supply across to the ecu output.
I can't see any reason it'd go to the 5v line. So you could do it either at the ecu end, or if more convenient at the cluster.
I'd think the ecu might be easier to access though ?
Although if indeed this AI google search is true.....it's odd for a modern car to still use a coil for the tacho. So to the 12v would be a good start.
I'd be shocked if you needed to wire it to a relay coil to get a decent voltage spike to drive the coil....although it was needed on some older cars with aftermarket ecu's
https://www.google.com/search?q=honda+fn2+tacho+si...
TBH I'd be surprised if the Honda was any different....but clearly it isn't working,
Martin's pullup resistor would most likely be from the 12v supply across to the ecu output.
I can't see any reason it'd go to the 5v line. So you could do it either at the ecu end, or if more convenient at the cluster.
I'd think the ecu might be easier to access though ?
Although if indeed this AI google search is true.....it's odd for a modern car to still use a coil for the tacho. So to the 12v would be a good start.
I'd be shocked if you needed to wire it to a relay coil to get a decent voltage spike to drive the coil....although it was needed on some older cars with aftermarket ecu's
https://www.google.com/search?q=honda+fn2+tacho+si...
stevieturbo said:
I don't know what the Honda outputs, but the Syvecs would just be a simple pull to ground.
TBH I'd be surprised if the Honda was any different....but clearly it isn't working,
Martin's pullup resistor would most likely be from the 12v supply across to the ecu output.
I can't see any reason it'd go to the 5v line. So you could do it either at the ecu end, or if more convenient at the cluster.
I'd think the ecu might be easier to access though ?
Although if indeed this AI google search is true.....it's odd for a modern car to still use a coil for the tacho. So to the 12v would be a good start.
I'd be shocked if you needed to wire it to a relay coil to get a decent voltage spike to drive the coil....although it was needed on some older cars with aftermarket ecu's
https://www.google.com/search?q=honda+fn2+tacho+si...
Stevieturbo, I was hoping you'd appear as you seem to be very knowledgeable with Syvecs.TBH I'd be surprised if the Honda was any different....but clearly it isn't working,
Martin's pullup resistor would most likely be from the 12v supply across to the ecu output.
I can't see any reason it'd go to the 5v line. So you could do it either at the ecu end, or if more convenient at the cluster.
I'd think the ecu might be easier to access though ?
Although if indeed this AI google search is true.....it's odd for a modern car to still use a coil for the tacho. So to the 12v would be a good start.
I'd be shocked if you needed to wire it to a relay coil to get a decent voltage spike to drive the coil....although it was needed on some older cars with aftermarket ecu's
https://www.google.com/search?q=honda+fn2+tacho+si...
I'm going to order up some 2K resistors and have a play. I've stripped the front/rear of the vehicle to access both ECU and tacho/shift lights to check continuity of the RPM signal wire. It will probably be easier to insert a pull up resistor at the tacho/shift light end.
If only the rev counter or only the shift lights were playing up since Syvecs install I'd probably suspect that it was a local fault with either the rev counter or shift lights. The fact that BOTH are playing up since Syvecs install makes me think it HAS to be an issue with the actual RPM signal from the new ECU.
Thanks again for your help
To diagnose the problem you'd need to know what sort of signal the rev counter and shift light expect (presumably they're similar).
If they expect a digital signal, you need to know if the ECU is capable of outputting a compatible signal. If it's analogue (ie they're intended to be connected to the coil LT signal) then the signal from the ECU may need some conditioning to make it suit them. It's common for aftermarket gauges and shift lights to support several options but less likely for OEM guages.
If they expect a digital signal, you need to know if the ECU is capable of outputting a compatible signal. If it's analogue (ie they're intended to be connected to the coil LT signal) then the signal from the ECU may need some conditioning to make it suit them. It's common for aftermarket gauges and shift lights to support several options but less likely for OEM guages.
GreenV8S said:
To diagnose the problem you'd need to know what sort of signal the rev counter and shift light expect (presumably they're similar).
If they expect a digital signal, you need to know if the ECU is capable of outputting a compatible signal. If it's analogue (ie they're intended to be connected to the coil LT signal) then the signal from the ECU may need some conditioning to make it suit them. It's common for aftermarket gauges and shift lights to support several options but less likely for OEM guages.
Many thanks for the help If they expect a digital signal, you need to know if the ECU is capable of outputting a compatible signal. If it's analogue (ie they're intended to be connected to the coil LT signal) then the signal from the ECU may need some conditioning to make it suit them. It's common for aftermarket gauges and shift lights to support several options but less likely for OEM guages.
The dash is a relatively old SPA Design KitDash with two analogue dials for speed and tacho.
https://www.gb-ent.com/products/spa-dash-unit-with...
The shift lights are a discontinued Shift-I unit
https://ecliptech.com.au/shift-i/
It looks like the shift lights can take a tacho signal from multiple sources, I wired it up as per the first of the methods below::
When I originally fitted this shift indicator, I used the same RPM feed going to the SPA dash and both have worked flawlessly up until Syvecs installation.
I've just tried putting a 2K resistor across the 12v feed and RPM signal going to the shift lights and no difference was seen. I tried the same with the rev counter and again no difference was seen.
I'm stumped
Just found the SPA Kit Dash manual online, it's the third link down here:
https://spatechnique.com/pages/manuals-electronics...
It states that the tacho + input from the ECU is "10K OHM LOAD ISOLATED". Does this have any bearing on the Syvecs ECU?
https://spatechnique.com/pages/manuals-electronics...
It states that the tacho + input from the ECU is "10K OHM LOAD ISOLATED". Does this have any bearing on the Syvecs ECU?
Is this the instructions ?
https://cdn.shopify.com/s/files/1/0280/2535/6347/f...
Seems weird they list a tacho ground, and then the tacho signal as a positive.
Equally, odd you have diagrams with wildly different signals, yet the dash will seem happy with all ?
https://www.maxxecu.com/webhelp/wirings-pullup_wit...
https://www.electro-tech-online.com/threads/amplif...
An old method to create a high voltage spike is using a simple automotive relay coil, where the ecu output charges this, and then the voltage spike to drive the tacho is created when power is removed. So the relay coil is largely behaving like an old inductive ignition coil would.
https://cdn.shopify.com/s/files/1/0280/2535/6347/f...
Seems weird they list a tacho ground, and then the tacho signal as a positive.
Equally, odd you have diagrams with wildly different signals, yet the dash will seem happy with all ?
https://www.maxxecu.com/webhelp/wirings-pullup_wit...
https://www.electro-tech-online.com/threads/amplif...
An old method to create a high voltage spike is using a simple automotive relay coil, where the ecu output charges this, and then the voltage spike to drive the tacho is created when power is removed. So the relay coil is largely behaving like an old inductive ignition coil would.
I see the dash has tach+ and tach- pins. What have you connected them to?
I've no experience with Syvecs but from what I can see from a random online manual, A14 is a general purpose injector/PWM output which would need to be configured to provide a tacho output signal. Have you configured it in the ECU configuration? What sort of output signal do you expect it to produce?
The Syvecs examples I've seen all show using the output being used as a pull-down. If you're using it like this, you'd probably need to connect the dash's tach+ input to +12V and the tach- input to the ECU.
I've no experience with Syvecs but from what I can see from a random online manual, A14 is a general purpose injector/PWM output which would need to be configured to provide a tacho output signal. Have you configured it in the ECU configuration? What sort of output signal do you expect it to produce?
The Syvecs examples I've seen all show using the output being used as a pull-down. If you're using it like this, you'd probably need to connect the dash's tach+ input to +12V and the tach- input to the ECU.
stevieturbo said:
Correct The instructions etc for the (discontinued) shift indicator lights can be found here:
https://ecliptech.com.au/shift-i/
stevieturbo said:
Seems weird they list a tacho ground, and then the tacho signal as a positive.
I don't know enough about electrickery to know if this set up is weird or not to be honest. All I know is it all worked for over ten years before the switch to Syvecs stevieturbo said:
Equally, odd you have diagrams with wildly different signals, yet the dash will seem happy with all ?
No, the diagram I posted showing numerous ways of getting an RPM signal is solely for the separate shift indicator lights, it is NOT for the dashstevieturbo said:
https://www.maxxecu.com/webhelp/wirings-pullup_wit...
https://www.electro-tech-online.com/threads/amplif...
An old method to create a high voltage spike is using a simple automotive relay coil, where the ecu output charges this, and then the voltage spike to drive the tacho is created when power is removed. So the relay coil is largely behaving like an old inductive ignition coil would.
That may work for the shift lights, the diagram I previously posted suggests multiple different RPM signals are compatible. Unfortunately, the dash instructions state that the RPM signal has to come from the ECU.https://www.electro-tech-online.com/threads/amplif...
An old method to create a high voltage spike is using a simple automotive relay coil, where the ecu output charges this, and then the voltage spike to drive the tacho is created when power is removed. So the relay coil is largely behaving like an old inductive ignition coil would.
Again, thank you for your help
GreenV8S said:
I see the dash has tach+ and tach- pins. What have you connected them to?
The dash came standard with the car and is wired to the original loom. The tach- is just a ground, the tach+ is the RPM feed from the ECU, so previously from the Honda Hondata ECU, and now from pin A14 on the Syvecs ECU When I fitted the shift indicator lights, I just used the same tacho- and tacho+ feeds, plus a switched +12V that was also going to the dash.
GreenV8S said:
II've no experience with Syvecs but from what I can see from a random online manual, A14 is a general purpose injector/PWM output which would need to be configured to provide a tacho output signal. Have you configured it in the ECU configuration? What sort of output signal do you expect it to produce?
I haven't touched any of the configuration etc of the Syvecs ECU, I left all of that to the company that installed and mapped the Syvecs. I wouldn't know how to configure it, or what sort of output signal it should be emitting as the RPM.GreenV8S said:
The Syvecs examples I've seen all show using the output being used as a pull-down. If you're using it like this, you'd probably need to connect the dash's tach+ input to +12V and the tach- input to the ECU.
I haven't tried this, it was suggested to me on a Syvecs group to try a 2K pull up resistor Thank you for the help
Edited by Toilet Duck on Friday 11th April 06:52
The polarity aspect of the dash is odd.
I would expect the dash to have a 12v, and then the ecu drive the tacho via a ground trigger. Not as it implies, a solid ground with a positive trigger.
Again, that would be more akin to a conventional inductive coil setup.
Perhaps you could try switching those wires ? give it a solid 12v, and apply the output to the -ve wire ?
The output will be configured already, you're only options will be pulses per revolution. It is a simple pull to ground output, square wave same as any generic ecu output.
martin would certainly be more knowledgable, but the post on FB didn't state what dash was being used.
I would expect the dash to have a 12v, and then the ecu drive the tacho via a ground trigger. Not as it implies, a solid ground with a positive trigger.
Again, that would be more akin to a conventional inductive coil setup.
Perhaps you could try switching those wires ? give it a solid 12v, and apply the output to the -ve wire ?
The output will be configured already, you're only options will be pulses per revolution. It is a simple pull to ground output, square wave same as any generic ecu output.
martin would certainly be more knowledgable, but the post on FB didn't state what dash was being used.
stevieturbo said:
The polarity aspect of the dash is odd.
I would expect the dash to have a 12v, and then the ecu drive the tacho via a ground trigger. Not as it implies, a solid ground with a positive trigger.
Again, that would be more akin to a conventional inductive coil setup.
Perhaps you could try switching those wires ? give it a solid 12v, and apply the output to the -ve wire ?
I'm happy to try anything as long as there's no risk of me blowing up any electronics etc. I'm not going to be back from work until late tonight so won't have a chance to try that until tomorrow evening at the earliest. Hoping to try the side lamp test mentioned on that Syvecs group tonight though. For anyone reading here, it was suggested that I put a 12v bulb across the +12V feed and RPM signal, the logic being if the RPM signal is a pulsed ground then the bulb will illuminate brighter the more you rev the engine.I would expect the dash to have a 12v, and then the ecu drive the tacho via a ground trigger. Not as it implies, a solid ground with a positive trigger.
Again, that would be more akin to a conventional inductive coil setup.
Perhaps you could try switching those wires ? give it a solid 12v, and apply the output to the -ve wire ?
stevieturbo said:
The output will be configured already, you're only options will be pulses per revolution. It is a simple pull to ground output, square wave same as any generic ecu output.
In the configuration of the RPM signal in Syvecs, are there multiple different types of RPM signal it can output? IE is it possible the tuner has simply configured the RPM signal in a "wrong" format that is not compatible with my dash tacho and shift lights, and it just needs "changing" in the Syvecs config?stevieturbo said:
martin would certainly be more knowledgable, but the post on FB didn't state what dash was being used.
I've just seen your post on there. Thanks very much for helping me on there. I had mentioned the dash was an SPA Design Kit dash but couldn't work out how to upload the manual (I have it as a PDF file). Appreciate you posting the link and pic, that's very kind of you.Thanks all
Slight update. I've just connected a bulb up to the RPM signal and +12V and the bulb failed to illuminate at all even with some revs. I also connected it to the RPM signal and ground just in case but again nothing. The bulb definitely works, I tested it before and after doing the above.
Toilet Duck said:
Slight update. I've just connected a bulb up to the RPM signal and +12V and the bulb failed to illuminate at all even with some revs. I also connected it to the RPM signal and ground just in case but again nothing. The bulb definitely works, I tested it before and after doing the above.
It should light a little.Can you go into Scal and manually trigger the output in test mode to see if it's working ? It should pull to ground, test light should be fine for that. That should verify 100% if the physical output is working or not
https://www.youtube.com/watch?v=sTwaOL353eE
stevieturbo said:
It should light a little.
Can you go into Scal and manually trigger the output in test mode to see if it's working ? It should pull to ground, test light should be fine for that. That should verify 100% if the physical output is working or not
https://www.youtube.com/watch?v=sTwaOL353eE
I will try and have a look tomorrow when I've got a day off. I believe the map has been locked by the installer/tuner so I don't know if that impacts whether I can try the test mode.Can you go into Scal and manually trigger the output in test mode to see if it's working ? It should pull to ground, test light should be fine for that. That should verify 100% if the physical output is working or not
https://www.youtube.com/watch?v=sTwaOL353eE
Again, thank you for your help
Toilet Duck said:
I will try and have a look tomorrow when I've got a day off. I believe the map has been locked by the installer/tuner so I don't know if that impacts whether I can try the test mode.
Again, thank you for your help
If it's locked, then you won't be able to access it to test.Again, thank you for your help
Why was it locked ?
stevieturbo said:
If it's locked, then you won't be able to access it to test.
Why was it locked ?
I was offered the map locked or unlocked. If it was locked then they would warrant the map. I assume that this is to prevent customers from randomly fiddling with the map and then complaining that they have running issues etc, if my assumption is correct then I can see their point. Why was it locked ?
I think I have probably gone as far as I can with this and will have to wait until the car goes back to them, I will update with the outcome.
Again, thank you for all the help, it's very much appreciated
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