BMW E30 Speedometer wrong speed

“hi mate, reffering to the speedo displaying wrong mph. I tried changing the whole cluster but the problems remains. All other gauges are working perfectly. The gearbox in my car is mint as it has only done 79k. The car am driving is a 1990 bmw e30. Please advise”

All right, now we’re getting somewhere. As you have a BMW, you should realize you have one of the most complex vehicles out there, though yours is a bit old and nowheres near as complex as a late model BMW. I assume the speedo worked correctly at some time that you had it and that no other modifications have taken place. If the gear box came out of another car, it may never work correctly as it wouldn’t be set up for your model, I see that a lot with guys using used transmissions. Now if your speedo used to work fine, and nothing has been changed on the car, then yes, something has broken. Unfortunately,BMW does not provide testing methods without the use of the BMW Simulator. Outside of a BMW dealer, no one will have this equipment to test things out with. Even though your BMW is old, it still has tons of parts that require BMW speciality tools to check things out with. Perhaps you can find a speedo shop in your area to take the actual speed head to and have them check it out IF they have the BMW tool. And if you think this is bad, you should see the computer consoles that are needed to even begin to access electronic repair in a late model BMW. People used to say fixing cars isn’t rocket science, but it’s rapidly becoming so today in many models. Now if your older BMW has the three piece speedometer cable set up, sometimes that little box that two of the cables screw into goes bad and changes the gear ratio. So if that’s the case, you might try replacing that box. Some have them on them, and some don’t, but if yours does, odds are its gone bad IF the speedo head you already replaced is indeed good itself (the problem with using used parts is You Never Know.) Good Luck,