This may be a stupid question, BUT...

Has anybody run a Microsquirt directly utilizing the 914 board? Using the stock relays for power and fuel pump control? Or, is this the norm?

The Megasquirt has its own separate relay board... But I'm now trying to do away with that.

Thanks,

Dan Noyes

I’m doing that right now. The Microsquirt uses the stock 914 relay board, though there is different wiring and an added fuse block.

Zach

I'm using another brand of ECU but I'm also using the stock relay board for powering up the ecu and the ecu controls the fuel pump relay.

YUP! Been running this way for 15+ years and various Megasquirt and Microquirt board versions. Cleanest way to go in my opinion. Microsquirt activates the FP relay in the same manner d-jet does (grounds the circuit to activate) so that wire is just a direct connection. ECU and Injector power can be pulled from the relayed 12V pin on that same 4 pin connector however you will want to add inline fuses for those.

There is one non critical but slightly annoying issue I have encountered on a couple cars wired this way where for some reason the main relay stays activated when turning the key off until some other load is placed on the electrical system (stepping on the brake, etc) I havent dug to far into it yet as it isnt critical to operation but looks possibly like voltage back-feed though the alternator light as pulling the bulb deactivates the relay. Read a similar issue that BMW guys were encountering where installing a diode on the alternator light circuit fixed the issue. May give that a shot. Just something to be aware of.

Best tip I can give you from my experience is to add service loops. Especially on your power wire coming out of the microsquirt plug. And leave some room between the plug and the start of your shrink wrap. I ran my car 1700 miles before developing a Gremlin in the wiring. The power is pin 1 if I recall. It is on the end of the plug. With the shrink wrap too close it was putting pressure on the female connector. After vibrating around for 1700 miles, the female connector started to loosen up (insert dirty jokes here) The problem that this caused, was the microsquirt would loose power for a nanosecond as it was running. This would then cause the system to think that the car was not running and it need to go the the startup sequence. Over fueling and more damaging, over dwelling the wasted spark and cooking it.
Hope that helps you avoid a potential headache.

Matt