I have an odd problem on my 1965 Jaguar S type with its auto enrichment device. It starts (just) but idles/runs poorly until warmed up.
The system is twin SU carbs and a simple third 'carb' that is solenoid operated and quite simply dumps additional fuel into the manifold. The solenoid actuates at below 30 deg and is very obvious in its operation (loud hissing) as a plunger lifts a 1/2" brass disc off a metered orifice allowing air and fuel to pass through to the manifold.
The solenoid operates and the plunger moves freely on and off the car with a nice hefty click but fitted with the engine running (I just short the solenoid to earth, bypassing the temp switch) it can't lift the disc off the orifice due to the vacuum at idle and the click is decidedly feeble and no hissing.
There is a 1v voltage drop due to the aged wiring loom but it doesn't matter if I hook up a direct feed from the battery - it still doesn't have the strength to lift the disc.
It's the original one, so do solenoids go 'off' with age?
Anyone have an idea of the resistance I should expect across the terminals?
Or is it something else?