Today I did some soldering and constructed the JimStim V1.5 stimulator board. This nifty little board is a MegaSquirt simulator that enables you to bench-test your MegaSquirt ECU by simulating all the necessary sensor inputs required for the MegaSquirt to work.
The MegaSquirts sensor inputs can be easily tested using JimStim. This is achieved through using potentiometers to variate sensor voltages to be processed by the ECU.
JimStim is capable of simulating the following sensor outputs:
- MAT (manifold air temperature)
- CLT (coolant)
- TPS (throttle position sensor)
- O2 (O2/lambda sensor)
Included also is a nifty micro-controller that allows JimStim to simulate a toothed wheel sensor signal, which in turn simulates engine RPM. This feature is especially handy as you can confirm that your MegaSquirt operates correctly in what is effectively a controlled test environment. When building a MegaSquirt (especially if it’s your first time building) it can be a lifesaver in identifying any issues with your MegaSquirt that could potentially damage your expensive EFI kit, as well being a HUGE timesaver (I can’t empathise this one point enough) when it comes to physically wiring the MegaSquirt into your car. For example, if you were attempting a first-start after a new install and encountered issues with establishing a stable RPM sync, you could can during testing that the MegaSquirt you built works perfectly and that the issue must lie somewhere else within the car.
Here are a few shots of soldering together my JimStim.