Can the mpg gauge be fixed easily on an e30?

[Kaz788]

hi, I was wondering if it was possible, to easily fix the mpg gauge without taking the whole cluster out? As I don't want to mess with the whole mileage etc

Thanks [/list]

[Brianmoooore]

Depends entirely what's wrong with it. MPG gauge requires signals from the road speed sensor and the fuel injector pulses.
If the road speed signal is missing the speedo and odometer won't work, and since you haven't mentioned that, I assume that signal is present. The fuel rate signal comes directly from the engine ECU, and while it's possible this has gone missing, it's unlikely.
The one and only time I have come across a cluster fault that caused just the MPG gauge not to work the problem was related to burnt out components on both the speedo circuit board and the SI circuit board. After a brief and unsuccessful attempt at repair, I binned the lot and fitted a complete replacement cluster.
The complete speedo. assembly in an E30 cluster is easily removed and can be transferred to a different cluster, but this won't help if the speedo itself is faulty. Fortunately, it's also very easy to adjust the reading on an E30 odometer to any figure you require.

[Kaz788]

Thank you for your response,

Yeah everything else works in my cluster, but the temperature gauge is temperamental, but a quick tap on the dash and it reconfigures

The mpg gauge upon starting the car jumps from 0 to full, then back down to 0 when driving, does the si board have separate batteries? Sorry if that's a silly question

[ross_jsy]

The temperature gauge has 2 brass nuts that come loose, causing that. Remove the gauge from the board, clean up the contact with contact cleaner and reassemble.

The SI gauge has batteries. If they need replacing, follow this guide:

http://www.e30zone.net/e30zonewiki/imag ... attery.PDF

[Brianmoooore]

The temperature gauge has 2 brass nuts that come loose, causing that. Remove the gauge from the board, clean up the contact with contact cleaner and reassemble.

Much simpler than that. The 4mm brass nuts are on the back of the cluster case - one for the temp. gauge and one for the fuel gauge. No need to strip anything down for this - just tighten the nuts, or replace with new ones, if they have disappeared completely.

The SI gauge has batteries. If they need replacing, follow this guide:

http://www.e30zone.net/e30zonewiki/imag ... attery.PDF

Note that the guide is based on an E28 SI board, with just one of the pics. being of an E30 board, and there are two different versions of the E30 board which use different and non interchangeable batteries. One version uses 1.2 volt rechargeable NiCd batteries (NiMH replacements can be used as a better replacement) and the other version uses non rechargeable 3.0 volt lithium batteries.

[ross_jsy]

I always clean the contact points on the board itself.

My current daily had an issue despite the usual tightening procedure. It all went away with a proper clean

[Kaz788]

So it just needs a clean? Omg that's awesome! E30 for the win!


Thank you everyone for the replies, you've really helped me out!!!