rev counter problems

[QuiteQuietCerb]

Hi, i have noticed sometimes when in neutral that the rev counter plays up between 200-1000rpm, and it gets more erratic when i switch on the radiator fan (the car has a fan overide switch installed).

Also when i start the car from cold in neutral again, the rev counter sits on zero for the first couple of minutes, if i blip the throttle it works

I checked the big fuse and it was ok, any ideas anyone

[BLUETHUNDER]

Even though you have checked the big fuse.It could still have a small hair line crack in it.I would change it altogether and then see what happens.

[airborne midget]

I have same problem, where is the big fuse located any body have a pic of it's location please

[BLUETHUNDER]

Its located behind the engine block under the center of the scuttle panel.

[QuiteQuietCerb]

thanks bluethunder, it did it today again and i replaced the fuse just to be sure but it didnt cure it. so it must be something else?

Edited by QuiteQuietCerb on Saturday 29th March 23:40

[Allandwf]

Hi,
Mine is exactly the same ! OK once warm.

[touching cloth]

Worth checking the cabling attached to each end of the big fuse (and also the connection to the alt) - one side of mine had blackeded up and also corroded quite badly where the cable joined the fuse post (not immediately obvious until you actually took stripped it down a bit) once cleaned up etc it was much better. I make it sounds like I did that but it was the Dulford boys over in Germany, they also mentioned that my cable as a whole felt brittle and quite old and ideally I should probably replace the whole lot soonish, anything that has the potential to limit the transfer of a nice strong charge from the alternator to battery will cause this sort of thing.

[QuiteQuietCerb]

thanks for this i will check it, need to find the alternator first though! I would imagine that if that was the problem i would be getting erratic readings with everything else my dash wouldnt i?

Edited by QuiteQuietCerb on Sunday 30th March 09:52

[Cerberab]

My rev counter used to be very erratic, especially when giving it some eeky - I was going to do the big fuse after it went in to my local alarm/ICE guru.
Turns out he found a real bad earth connection (which included the ECU)and now it works perfectly!

Not sure where it was though - assuming it was to the chassis behind the dash somewhere...?

[QuiteQuietCerb]

Thanks for the responses guys, i was suspecting an earth also. I measured the battery voltage today with the car idling and it read 12 volts, i think it should be 14v? revving the car it went up to 13.5v, so im thinking maybe battery or alternator needs to be checked? if i had earthing issues the battery should be reading 14v on idle anyway.. shouldnt it?

[marcus1970]

QuiteQuietCerb said:

Thanks for the responses guys, i was suspecting an earth also. I measured the battery voltage today with the car idling and it read 12 volts, i think it should be 14v? revving the car it went up to 13.5v, so im thinking maybe battery or alternator needs to be checked? if i had earthing issues the battery should be reading 14v on idle anyway.. shouldnt it?

Post your findings, most people suffer with this.

Mine is always like it on a cold morning. Sometimes it works, but then when lights go on or heater as stated above, it reads 0. Then its fine when the car is warm.

Would be nice to sort this one out.

MB

[BLUETHUNDER]

I always thought it should put out 13.5 at idle and hold it.If the voltage does drop under revs.Then suspect the battery or alternator.My feeling is you have a dodgy earth.If the fuse is ok.Then like T.C said check the connections going in to the fuse block.

[QuiteQuietCerb]

BLUETHUNDER said:

I always thought it should put out 13.5 at idle and hold it.If the voltage does drop under revs.Then suspect the battery or alternator.My feeling is you have a dodgy earth.If the fuse is ok.Then like T.C said check the connections going in to the fuse block.

i will check the battery again, when i checked, the voltage increased when revving, but it was lower than 13.5 at idle anyway.

There is an earth point on one of the chassis tubes next to the engine (the side of the battery), the wires on it look pretty secure, any other earth points i should be checking ?

BTW i will post my findings at the end

Edited by QuiteQuietCerb on Sunday 30th March 22:35