charging problems / fluctuating guages

Rowdy · Post by **Rowdy** » 06 Nov 2023, 09:22

I had a problem starting the engine, as though the battery was flat, so I replaced it with a new Lucas one, it started. I went for a 20 mile drive when the dash board instruments ie. the speedo / rev counter started to flick up and down on their own and the fuel guage/temp guage also. I stopped the engine, but the new battery appeared flat (no power) someone gave me a jump from his battery and mine started. No more problems with the guages, all reading correctly now. Drove home without any problems. I fitted a new alternator ( one with the voltage regulator fitted into the back of the alternator ( as it should be on my 1999 240 2.3 petrol ). The starter moter then decided to pack up, so I fitted a new one, now starts no problem. Battery earth cable from battery all making good contact to earths ie. engine and body. The battery may not be charging properly, when the engine is running the battery is only reading 11.90 volts, should it be more than that? I have checked,the fuses in the car, which are all alright and there does not appear to be any short circuits anywhere. Has anyone any ideas as I am now desperate to resolve the problems.

Post by **Krons** » 07 Nov 2023, 04:56

Rowdy wrote: ↑06 Nov 2023, 09:22 The battery may not be charging properly, when the engine is running the battery is only reading 11.90 volts, should it be more than that?

Yes. Should be 13v or higher when running, you need a new alternator.

Rowdy · Post by **Rowdy** » 07 Nov 2023, 07:36

I have fitted a brand new alternator, still no good. It`s an absolute mystery to me.

Post by **Krons** » 08 Nov 2023, 12:51

Rowdy wrote: ↑07 Nov 2023, 07:36 I have fitted a brand new alternator, still no good. It`s an absolute mystery to me.

Either new alternator is bad or wiring to it is an issue?