I have a sporadic event on engine start. Every so often the digital display can either flash and the needles on the instruments spike (swing up).

One time the digital display had a single straight line in the upper part of the field and didn't work again until a restart later on - had been sitting in the sun for a while when this event happened.

Some sort of electical surge???

I'm concerned that this fault could lead to more serious issues as I've heard electrical issues can be bad in a 928 - any ideas how to tackle this?

I have a right hand 1990 S4.

Thanks in advance

 

its time to clean all of the grounds and the power supply wires.
Start at the battery , inspect the starter and engine main ground as well as all of the fuses and relay pins also the hot post and the 14 pin connector. if none of these cleaning procedures help then try cleaning the pod connections. you can use a eraser to clean all of the connections.
get a fuse relay chart here 928gt.com verify the correct fuse and realy are in the correct positions .

 

This happened to me when I parked in the sun. I did ask and do the suggestions of cleaning contacts to no total resolution. Since I have been parking in the shade the problem has not returned.

 

You almost certainly need a new battery.. This happens when the voltage drops too low during cranking. It could also be a connection issue somewhere - but more likely just a battery fault.

Take it in and have it checked properly - you may have a dead cell or just a high internal resistance.

Alan

 

Thanks guys for your thoughts - I'll work through the points your suggested. The battery seems like the most straight forward starting point. Cheers appreciate the input.