Non starting; 1993 Honda D16 engine

Hi,

I've got a non-starting problem on my 1993 Rover 216 SLi, which is taking me a long time to diagnose. There were no warning symptoms that there was going to be a sudden refusal to start. Engine turns over OK, occasionally there is a pathetic ignition happening, but only with assistance from the starter motor, no ECU codes, fuel supply seems OK, changed igniter unit, it sparks against the rocker cover OK (all plugs), timing belt looks in good nick (I changed it 20,000 miles ago), no obvious leaks etc in vacuum lines.

Then I noticed that the pin on the dashpot diaphragm (see here;

), which as far as I can remember always shoots in towards the pot during starting wasn't moving. Having used this as a potential lead, and having looked through a few other systems, I've found that the EACV solenoid clicks when plugging it in or disconnecting it with the ignition on. This flowchart;

suggests to me that it shouldn't (the point where it tells you to turn the engine on and check for voltage across the terminals suggests that there shouldn't be any). Unplugging the connector with or without the ignition on doesn't throw an ecu code, and neither does attempting to start the engine with it disconnected. I do manage to get a code (10) if I disconnect the injectors, but can't get it to complain about having no lambda sensor either if I disconnect it.

Does anyone have any suggestions/advice about the eacv (or anything else!!)?

Thanks

Derek