#1227, "RE: MegaSquirt Ver.3.0. Install" In response to In response to 3 Aug-28-05 07:58 PM by ner947
Build up just about everything... R37 and R38 are optional, they are sort of expensive and not really needed. The only reason they are there is to offer protection if you short the injector wires to something. If you choose not to use them a 14 or 16 gauge wire installed as a jumper will work fine.
Q16 (a VB921 transistor) and R43 are only used for people with single coil pack setups, like a V8 with a distributor. I don't have those populated on my board. If you want to run spark and not use an external module like a MSD box or a 4G63 transistor you will need to have 2 VB921's wired up in the proto area with a good heat sink.
I didn’t really elaborate about the 2 resistors in my previous post because I was on my PDA... If you are going to use the VR circuit you will need to use the "VROUTINV" setting. Those two blue variable resistors will need a bit of tweaking of the zero crossing point and the hysteresis to get the CPU to see the crank angle signal. I used an arbitrary waveform generator set to make a square wave at 0-5 volts simulating a real crank angle sensor to get it perfect, but not many people will have access to such a device. Although if you hook your MS to the stimulator (a 0-12 volt square wave), enable the 420A decoder, and enable "Stim for wheel" in MT with 2 steps per output, play with one resistor until the RPM's drop to 0, then back off a turn or two, then do the same with the other resistor. This seems to work just about as well as hooking the board to a real 0-5 volt signal.
