Rev Counter and dials dropping

[n9kie]

Hi there

I was wondering if you could help me with my first problem since buying my new williams

when the car is running, the rev counter is good but if i turn the lights on or activate the windows the rev counter neddle drops.

I have also noticed if you try and do the windows up when they are already up the oil temp and water temp guages drop along with the rev counter

also the radio will work for a while before the sound cuts out and it just beeps

I'm thinking a bad earth somewhere???

what are your thoughts??

[robi1000]

Usually bad earth.

[Laine_16v]

Main earth point is passenger footwell, behind the piece of trim that runs at the bottom, but at the front. 1 x 10mm nut holds on a eyelet with 3 earth cables from memory.

[n9kie]

Nice one I'll take a look! The earth from the negative battery terminal to the front of the car looks quite bad too!

[Wobba]

Nice one I'll take a look! The earth from the negative battery terminal to the front of the car looks quite bad too!

That's always a good one to give a scrub and clean up ;)

[n9kie]

I have cleaned all of the earths

1. from the negative battery terminal to the body
2. from the negative battery terminal to the gearbox
3. the one in the passanger foot well

the problem is still there

the rev counter also does not keep up with the revs of the engine! just as a test i hit the rev limiter and the rev counter was reading 3000rpm

something isn't right

any thoughts??

[fab]

there are 3 negatives on the gearbox. one on the front and one on the back that the loom attach's to. the third is the one that the lads pointed out that runs to the n/s arch.
other than that you have the one that runs from the battery negative to under-neath the slam panel and another just under the near/side light. (have a look at this one) this is mora than likely the culprit as it plays havoc with lights and switch's when not attached.

[n9kie]

all earths are clean but the problem is still there!

another thing i have noticed is - if you press the electric windon switch up when the window is already closed the dash battery light flickers as well as the rev counter dropping??

[fab]

does this happen with engine running or not?
get a multimeter on to the battery and check the voltages. also check voltages when engine is running. should be 14.45 me thinks when engine is running.

[n9kie]

Only really happens when the car is running! I will
Check the alternator charge tomorrow and let you know