EMU Black (3.044) running 3.2 liter air-cooled Porsche (non-turbo). Engine starts easily and reliably, runs ok until approaching 5000 RPM, causing trigger error “FALSE PRIM TRIGGER, FILTERED”. Engine stumbles, but recovers and runs.
Primary trigger sensor is VR, CAM1 sensor is Hall effect.
I’m surprised that “CAM1 input level” appears erratic, but I have “Disable cam sync above RPM” set to 3000 so it should not matter in this case, right?
20250310_1352_40.emub3 (62 KB)
20250311_1108.emublog3 (3.4 MB)
Do you have something wired to the CAM2 input on the emu?
No device on CAM2. I do have a wire connected for future expansion, but nothing connected to it. Log shows CAM2 signal present = “NO”. CAM2 input level is consistently “High”. In trigger configuration, CAM 2 pattern is “Do not use”.
Thanks for responding.
1 Like
Forgive me as I am not 100% sure on this but if that wire connected to the CAM2 input is bundled up next to other wires and is not shielded from them, that could be causing interference with that CAM2 wire.
Additionally, you want to use as low of a pullup resistor as possible to get a clean reading on your Hall sensor, maybe try lowering it to 820 Ohm and same goes for your crank sensor. If you are getting a nice solid signal without the need for a pulldown, then don’t use it. In reality once the car is up and running (sync’d up) then you can disable the secondary trigger at as low an rpm you want to as the EMU will still fire the car just fine since it is already sync’d.
I have the secondary trigger disabled above 600rpms on my Honda because the distributor wiring for the cam and crank signals were just causing too much interference with each other. Car runs and drives just fine like this, revs to 8000 rpms smoothly while making 13psi of boost on top of it.
Here’s my configuration for CAM2:
I’m assuming “Do no use” means anything on CAM2 is ignored.
Here are three examples of the trigger problem:
Not all have the “FALSE PRIM TRIGGER, FILTERED” message, but all show the Trigger sync status going to NOSYNC.
Are your cam and crank sensor wires shielded? If not they should be. Also consider lowering the pull-up voltage to 820ohm and not the 1k you had it on.
Crank (VR) and CAM1 (Hall) are each connected to EMU with shielded twisted pair. Shield drain connected at EMU end only.
Do you mean Pulldown 820 Ohm (not pull up)?
Look at my screen shot here which shows a 820ohm PULLUP as I stated. Reason being is that some hall sensors already could have pullup resistors built into them and if you are now trying to add another one on top of that, it’s too much.
Try lowering the pullup to 820ohms and see what happens. Also does this cutting out occur after the car has warmed up? It looks like your hall sensor is faulty and/or simply can’t provide a stable/fast enough signal as the RPMS rise. You may want to try switching to a mag style sensor if there is a provision for that. You could also try disabling the cam sync to a lower rpm range and possibly try turning on the advanced filtering.
I think that your cam sensor is failing though as hall sensors are affected by heat/magnetic field (interference) a lot more than a VR sensor.
I was fixated on the crank sensor; I see you’re suggesting 820k pull up on the cam sensor. Got it. But does that matter if I have have “Disable cam sync above RPM” set to 3000? The failure is happening well above 3000 RPM.
Your suggestion led me to double check the cam sensor instructions. It calls for a 1k external resistor connected to +12V. I’m no EE, but in terms of current flow that works out to about the equivalent of a 420 ohm resistor connected to +5V (since the EMU internal pullups connect to +5V). So I think you’re on to something, a lower value pullup is needed. But, back to the comment above, does any of this matter if the cam sync RPM is set low?
Thanks for the comments.
Pull-ups AND Pulldowns are only there to condition a poor signal. If I don’t need to use them, I don’t. It even states this very thing in the help section on the EMU black. Try and use the lowest value possible. Same goes for filtering (try to use the lowest value possible)
It does matter in your case because your CAM signal is erratic at all times. Not just above 3k rpms.
Also I don’t believe you mentioned if this is happening when the car is cold or completely warmed up?
As I mentioned above try this in this order: And go for a drive to test it out to verify after each step.
- Lower CAM pull-up to 820ohms
- Lower CAM sync RPM to 1000.
- Apply advanced filtering on CAM signal
- Switch to a VR sensor (if possible)
I really think that your problem may be:
- Failing or faulty/old cam sensor
- Not up to the task if reliably providing signal at high rpm’s where a VR sensor would be more stable.
Side note: consider removing the wire you have in the CAM2 pin. Even not connected to anything, if it’s bundled up next to other wires it will receive interference. I honestly see NO other reason for you to get a “CAM2 false trigger” error unless there wasn’t a wire in that pin. Even if you have “don’t use CAM2” input selected on the EMU.
Try to increase the crank sensor gap. Check if that raise the rpm where its hapening. You can also add a resistor in line to your crank signal wire
ECUMaster Support recommended eliminating the Primary trigger pulldown. That fixed my issue.
There were never any CAM1 or CAM2 errors.
Thanks.
1 Like
