Erradic cluster guages

[haroldk]

Bought an 85 318i,200k with car in general great shape.Cluster guages didn't work right.Temp and fuel not reading correct.Tac goes wierd berween 1500 and 2500rpm.Speedometer works on and off.I replaced both the SI and main cluster printed circuit boards with Programa rebuilt/guaranteed boards but NO change.I replaced a fried ground wire on the alternator and also noticed a burnt connection comming out of the main wire harnes to the right of the battery comming out of the firewall.No way to check but I presume this connection is still working.My main concern is if these two shorts could of damaged something that feeds the cluster.Does the ecu have anything to do with the cluster?Any thoughts would be appreciated.

[Jaxx_]

fuel and temp require a good ground. there is a nut on the back that needs to be tightened, it's also the ground for the gauge. I'm unsure about the tach.

usually simply tightening those small nuts on the back will fix most of the issues because of the way the gauges need proper voltage and ground to display accurately.

[Jaxx_]

and often times issues with the speedometer are issues at the differential, not the cluster. but not all the time.

[Adrian_Visser]

Congratulations you bought a 26 year old e30 they come stock with a fucked up instrument cluster. If it's any consolation my '89's cluster is a cluster fuck too.

[ill4noreason]

My tach worked fine until I took the car to get painted then it stopped working mysteriously. Now the light flashes on and off. I think its a loose ground wire. There easy enough to pull out and check anyway.

[haroldk]

Adrian,I have not heard that these yeard 318's are cluster prone.I know about ALL the grnd areas and after replacing both boards I thought sure I had it fixed but NO change.The speedo could be a rear end problem but the previous owner put in a new sender so that somewhat limits that?I'm afraid something got fried from the shorts I described(pix of one)That's why I asked if the ECU has anything to do with the cluster?Thank's bud,Nice car you have,Harold