the 3800 (L36) engines built after 1998 use drive-by-wire throttle. The same throttle control also operates idle speed so no IAC valve. I would like to support an IAC valve so I am going to use a 97 throttle body and intake manifold which supports IAC.

Left TB is pre-98, right is drive by wire 98 and later TB.


Worked on the Megasquirt system, finally got the circuit boards. the assembly was a lot easier than I though. Never done any soldering before on a PCB. There are silkscreen icons of all components and component number is referenced on each package.

This is the megasquirt relay board which is designed to simplify wiring into your harness. You can mount this guy under your hood and mount the main board in your cabin. A 37 pin cable is used to connect the relay board to the main board.

The kit includes a case with an open top, and single screw-in connectors you are supposed to solder in. I think I might solder the wires directly to the board and use a 20 pin connector in case I have to disconnect it. That way I can seal the whole thing with epoxy.


here is the megasquirt stimulator. It is a component you build for testing purposes only. It simulates all the reference voltages sent by all of your sensors (IAC, CLT, TPS, O2, etc) so you can plug this guy into your mainboard during construction to verify everything is working correctly. The main board connects to your computer via serial cable and megasquirt's tuning software (megatune) lets you see all these outputs in real-time. You are supposed to use the little black pots that is similar to the little black on there on the right. The other types were on backorder so I had to use these old ones I bought at radioshack. It doesn't really matter though, this thing stays on your workbench and is not part of the system after construction.


This is the half-finished mainboard.
I'm waiting for a heatsink which is supposed to mount on the aluminim strip at the top. I haven't installed the voltage regulators, IC chips, or transistors yet since they are static sensitive. The 37 pin connector will connect to the relay board and the 9-pin connector will connect to a laptop for tuning. Under the board is a soldered-in MAP sensor which will connect to my intake manifold via tubing. This will make a speed density fuel injection system.

So far I'm glad I did this versus using the stock computer. we'll see how it turns out.