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Getting fuel pump to prime on acc switch

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I have a motec Gold box with me, old so called “tune” had the pump to prime and automatically dump a load of fuel to the rails once the key had turned the acc switch on.

Now after a format, its not doing it anymore. Yes i have designated the fuel pump to its old aux port as its wired via software. Its aux 4 for now, and it does retain the relay. Output test makes the fuel pump work everytime yes.

so what setting am I missing?

Can you compare the old and new ECU configuration files? If I had to guess, I bet it something like Adjust->Fuel->Compensations->First Injection or Stopped Injection (that only happens if TPS > 90% -- perhaps a clever config had no TPS, but set to default to >90% so a pulse when key on.)

If you're not getting the pump on at startup, perhaps you need to adjust Auxiliary Output Functions-> Aux 4 - Fuel Pump-> Parameters->Delay to be non-zero?

I never had the old file. The guy that did the tune deleted it because he wasn’t willing to remove my password. Anyway, he was a terrible person. So i have to start fresh.

I saw you asked this question again on the MoTeC forum. What are your parameters for the Fuel Pump Function (i.e. Adjust->Auxiliary Output Functions->Aux Out 4 - Fuel Pump->Parameters)?

Seems like you need to have a non-zero number for Delay (say 2-3 seconds), and the Polarity & Output Mode need to be correct. Test by resetting the ECU to confirm the fuel pump runs for "Delay" amount of time.

You can test the Aux4 Output to determine which polarity is correct using Utilities->Test Outputs...

Good Luck!

Nice detective work. I cant hide myself on the internet either, people just find me out. Thats why I also avoid kinky websites or I will be in the news. Yeah the guy politely asked me to mak my own thread or F off so I didnt trigger him no more.

I did what you said last time and saved the tune file in motec folder but havent loaded it on to the ecu yet. For now this ecu primes on output test. And that proves polarity is correct.

In axis setup i did set a 2d table against tps and Rpm with 40% on 0%tps. All the way 5-10% increment till 100% on 100 tps. Dont know if it would adhere to it though as the relay is mechanical not solid state.

Really love the fact that you take time to reply. Respect.

I don't think you will have a good behavior using a PWM for a standard relay. Just switch that on/off (100%/0%).

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