MegaSquirt v3.0

Jacque8080 · 10-19-2005, 10:04 PM

Hi,

I don't usually post much. But my W Body has been broke for a while now. I was in the middle of a swap from a 3.1 MPFI to a 3.4DOHC. It turns over and sparks. But the fuel injectors won't fire. So I got my hands on a megasquirt. I'm using it to fire the injectors. I unplugged a fuel injector and connected to an analog multimeter. The needle would barely wiggle back and forth 0 to 2 volts as I cranked. So I believe the injectors are opening. But are they not getting enough voltage to fully open? Or is something else wrong? The fuel pump primes and the fuel rail becomes pressurized.

It's just over 2 years that I've been working on this thing. I'd appreciate any suggestions to keep it from turning into 3.

**SappySE107** · 10-19-2005, 10:23 PM

First off, use the DOHC computer to diagnose this, not another computer which could add to the problem. If the injectors don't fire, its either a fuse, bad ground, or ECM problem, since you do have a spark. Are you sure your injectors are good? Have you ohmed them to see if they are screwed internally?

Jacque8080 · 10-19-2005, 10:35 PM

I"ll pull the Megasquirt off the car. (It ran my friend's VW Scirocco.) The ECM and injectors are off of a donor car that I drove to my garage. How much resistance should I get from the injector? Besides that, the ECM sends power to the injectors directly, without any fuses (at this time). I will check the ground wires for good connection and/or run a wire to the neg. side of the battery.

Thank you so much.

**SappySE107** · 10-19-2005, 11:25 PM

The computer constantly sends power to the injectors, but pulses the ground to complete the circuit. You should have around 12-14 ohms. Ill double check with the set I have here.

eliteweapons · 10-21-2005, 12:22 AM

yes most gm injectors are high resistance 12 ohms.