MicroSquirt.com read only forum (Jan.15,2018)

I have hooked up the injectors then pluged in the ecu. When it turns on there is a small click. Then i hooked up the fuel pump relay and there is a louder click. Is this normal to click? I used a volt meter and i get 12 volts at the fuel pump until it clicks then nothing. Sorry for the simple questions but this is all new to me and i don't want to screw it all up.

1Fast7 wrote:I have hooked up the injectors then pluged in the ecu. When it turns on there is a small click. Then i hooked up the fuel pump relay and there is a louder click. Is this normal to click? I used a volt meter and i get 12 volts at the fuel pump until it clicks then nothing. Sorry for the simple questions but this is all new to me and i don't want to screw it all up.

The injector first click on powerup is the priming pulse, this is a one-time activation of the injectors.

The relay click on powerup is to close the relay contacts to supply fuel. This happens because of the injector priming pulse - anytime there is injection actuation the fp relay is pulled in. Now, after it is pulled in, if there is no tah pulses within 2 seconds then the relay should click again, open. So apply power and wait for the big relay click, then 2 seconds later you should hear the relay click again to turn off the fuel pump.

- Bruce

1Fast7 wrote:I have hooked up the injectors then pluged in the ecu. When it turns on there is a small click. Then i hooked up the fuel pump relay and there is a louder click. Is this normal to click? I used a volt meter and i get 12 volts at the fuel pump until it clicks then nothing. Sorry for the simple questions but this is all new to me and i don't want to screw it all up.

I re-read this, is the first click you hear the injectors or the fuel pump relay? You should hear both click on immediately when you apply power, then the two-second timeout with the relay opening again - I think this is what you are describing. And if this is the case, you will measure the +12V at the fuel pump terminal, then two seconds later when relay clicks again the +12V goes away.

Am I describing this correctly?

If you want to make some tach activity (to keep the relay open longer), you can apply some pulses to the tach circuit. MicroSquirt has both Opto and VR, and you will be only using one or the other, so here is a quick description on how to make random pulses using the other "unused" tach input:

1) If you are using the VR sensor hookup, then you can feed a signal into the Opto circuit - temporarily hook the Opto- wire (mislabeled Option-) to ground and tap the Opto+ (again mislabeled Option+) on the +12V battery terminal rapidly. Tap it real fast - you will see some RPM activity on MegaTune, and the fuel pump relay will stay closed. When you stop with the tach pulses, two seconds later the relay will open.

- or -

2) If you are using the opto circuit for your tach trigger source, you can tap a signal on the VR1+ wire just by tapping the wire to ground. Tap rapidly and you will see tach activity on MegaTune and the relay will stay pulled in, when you stop two seconds later the relay will open again. Note that with the opto circuit you may have to disconnect it while tapping on the VR if the source generating the tach signal is always at +12V.

Also, if you have a VR sensor hooed up, often you can just tap the tip of the VR sensor with a screwdriver, this often causes enough change in magnetic flux to be picked up as a tach pulse. I do this all the time just as a quickee test of the VR circuit.

MicroSquirt is a bit harder to get going compared to MegaSquirt mainly because of the lack of a stim setup, so you have to use the engine as a "stim"...

- Bruce

Yes you are right. I didn't think about the system presurizing and priming for start up. My first thought was i had something messed up causing a overload and shuting down. Although i have been over the wiring 100+ times i just don't trust myself. I don't need to blow it up. Thanks for your help it helped to know that all was right. Now if i can firgure out this ignition i'll be alright.