EVAP Valve - Technical Puzzle

[Rek]

Technical question. I have a later 1989 M30 engine in my E9. It has a wiring connector for an Evap valve but the input to the manifold is blanked off. I currently have a resistor across the connector, but that only solves the engine management light in the E34 it came from, per another forum. My warm starting is not great and Mr Haynes says that is a symptom of a bad Evap valve. I guess an Evap valve is quite bad if it isn’t there. Any ideas on this.

The engine came from an Alpina B10 3.5, if that helps. It might be that they deleted the valve but not the wiring loom as the conversions in 1989 were completed by Sytner in the UK.

 

[Blinkling]

Perhaps your car is running too lean on startup because it’s not consuming the vapors it’s expecting from the gas tank and charcoal canister. That’s where your theory seems to be leading…

Two tests of that theory:

1. Put a light bulb in place of that resistor. Put it on an extension wire and mount it on your hood with a magnet and then go for a drive. It should help you understand where in the cycle the EVAP routine is supposed to be. Maybe it is on startup? It isn’t on my early 90s Ford.

2. Route a hose from your tank to a vacuum line and see if the abundance of vapors during warm startup indeed helps. Check for vacuum leaks while you’re at it.