MoTeC Global Forum

Hello,
when I am running my engine (1 cylinder) with an M130 GPR on a testbench, I always get the warning "Fuel cylinder 1 Primary output Diagnostic = limit", so the injector pulse is being detected at limit angle.
my fuel timing primary main is at 200°BTDC, the fuel timing primary limit at 180°, and the fuel timing primary edge is at "End of injection"

I thought, that end of injection means that that the injection ends at 200°, and the motec calculates the start of injection based on the other input parameters. Unfortunately I couldn't find an explanation for this. Can you tell me where the problem is? I have attached my recent package to this post.

Best wishes,
Patrick

Hello Patrick,
If it is a Limit diagnostic this will come from the ECU extending your fuel pulse while the injector is open. The ECU is able to recalculate fuel volume requirements while it is actively injecting fuel, this could be from something like Fuel Film. Because you have a fairly tight window to add extra fuel, only 20 degrees you are more likely to get this diagnostic appear. EOI Fuel Timing for a port injected engine is usually higher numbers like 270-360 for example. The Fuel Timing Limit is normally considered to be where the intake valve is closed so this will depend on your cam shaft.

Feel free to send some logging with the diagnostics and fuel pulse width logged at high rates. You should also log the Fuel File Trim at high rate as this is an example of what could be adding fuel volume.