How to troubleshoot a diesel engine that won't start in cold weather?

I have a 1995 Audi 80 with a diesel engine that starts fine in warm weather but struggles to start in cold mornings. I have changed the glow plugs and checked the battery, but still no luck. Any suggestions on how to fix this issue?

First, make sure to check the fuel quality and ensure there is no water or contaminants in the fuel. If the fuel is clean, try using a diesel fuel additive that helps with cold weather starting. Another tip is to let the glow plugs warm up for a longer period before starting the engine.

Have you checked the glow plug relay? It may be faulty and not sending enough power to the glow plugs. Also, inspect the wiring for any damage that could be causing a weak connection.

In addition to checking the glow plugs and glow plug relay, it is also important to have the battery tested. A weak or old battery can struggle to provide enough power to start the engine in cold weather.