Fix for SVX stalling issue with stock ECU and manual transmission

[mattmoox]

Hi folks,

For those of you with an EG33 with the stock SVX ECU and a manual transmission: you are likely experiencing stalling when coasting to a stop when the engine is hot. This is due to the ECU being programmed for an automatic transmission which triggers Deceleration Fuel Cut Off (DFCO) when the engine is hot and you are coasting/decelerating to a stop.

I have a simple fix for this which has been working well for me in a variety of driving conditions: When depressing the clutch (and ONLY when depressing the clutch), ground the ECU Neutral pin (B10) and add a 200 ohm resistor in series with the coolant temp sensor. This can be achieved with a switch on the clutch which triggers a DPDT relay.

The reason this works is because the additional 200 ohm resistor in series with the coolant temp sensor tells the ECU that the engine is not fully warmed up. When the engine is not fully warmed up, DFCO is disabled.

Before implementing this mod, be sure to make sure the following components are set to stock settings: TPS, throttle stop screw, IAC valve, Aux air bypass valve. If you are like me, you probably already spent hours fiddling with these to solve the problem, to no avail. Enjoy.

Cheers,
Matt
Fairfax, CA