I wonder how ECU knows a glow plug is bad? ECU only controls timing by sending a signal to the glow plug rellay that switches higher current to the glow plugs. Rellay circuit as i see it purely mechanical rellay, so I guess ECU has no back info about current not being drawn by the plug.
For example if engine is cold and one plug is detached there could be a missfire at the begining and ECU could detect that by monitoring spikes in the cranksfaht speed. But this will turn on missfire light etc.
In my case (one plug being broken ) ECU turns on glow plug problem light imidietly, you don't even need to start the engine. The light turns on even if I connect a new glow plug to the connector and plug glows (just plug itsels isnt mounted into the head).
Any ideas?
Relay is tested with light bulbs and is fine.
For example if engine is cold and one plug is detached there could be a missfire at the begining and ECU could detect that by monitoring spikes in the cranksfaht speed. But this will turn on missfire light etc.
In my case (one plug being broken ) ECU turns on glow plug problem light imidietly, you don't even need to start the engine. The light turns on even if I connect a new glow plug to the connector and plug glows (just plug itsels isnt mounted into the head).
Any ideas?
Relay is tested with light bulbs and is fine.