Rev Counter problems.

Technical Help for the A & K Series Metro. Please state what year and model you're referring to for better responses.
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RoverMetro1991
Posts: 2
Joined: Tue Oct 20, 2020 6:26 pm

Rev Counter problems.

Post by RoverMetro1991 »

Hello
I have a 1991 Rover Metro 1.1L which has the 1.1 litre 8 valve K series with a carburettor.

I recently bought an instrument binnacle with a rev counter, and because mine has a rear windscreen wiper it has the wire from the coil already fitted so it should just work, according to the Metropower guide.
However, after plugging it in and starting the car I have discovered that when the engine is at idle (engine was cold so probably 5-600rpm) the rev counter was at 0 still. When you raise the revs the gauge does begin to work, but when it's at 1000rpm the engine is doing considerably more than this (probably 2000 or more).
Does anybody know what could be the cause of this?
Are they different on the fuel injected cars and, if so, would it cause a fault such as this?
Thanks,
Ryan.
Dave VVC
Posts: 80
Joined: Thu Mar 16, 2017 7:40 pm
Location: West Mids

Re: Rev Counter problems.

Post by Dave VVC »

Hi, it may be a sticking gauge,
the wire you should have is coloured white with a black tracer
from the coil neg terminal.
I would try the gauge in a car that has a rev counter as std to
see if yours works as it should.
RoverMetro1991
Posts: 2
Joined: Tue Oct 20, 2020 6:26 pm

Re: Rev Counter problems.

Post by RoverMetro1991 »

Hi Dave.
Thanks for replying.
The needle on the rev counter moves freely and when you rev the car it moves freely, its just that it seems to underread by quite a lot.
I'd like to try it in another metro but I only know of one other near me, and theirs doesn't have a rev counter.
Do you know if there is any differences in the way that the rev counter gets it's reading in a fuel injected one?
Do fuel injected ones get the reading from the ECU, and as mine gets it from the coil it doesn't read correctly?
Thanks,
Ryan.
Dave VVC
Posts: 80
Joined: Thu Mar 16, 2017 7:40 pm
Location: West Mids

Re: Rev Counter problems.

Post by Dave VVC »

Iirc mems 1.6 ecu equipped cars (metro GTi, alloy inlet manifold) 3AS alarm gets rpm
signal from coil neg-ve White/black wire.
mems 1.9 ecu cars, metro/R100 with plastic inlet manifold and mems3, 5AS alarm gets rpm signal
from ecu, but still has same wire colour White/black at the dash plug,
now, early rev counters had a adjustment in the back that alters the needle position,
early rev counters have the temp and fuel gauge needles hanging down, not the horizontal
needle gauges with the freeze gauge fuel.
its not a user adjustment bit, but it's set at the factory, but it will enable you to set the needle
in the right position for idle for instance, I set mine using a Snap-on digital rpm strobe gun by
raising rpm to 3600 (about halfway through rpm range), then cross checking digital to needle
position,
The adjustment in the back of the gauge is a circular bit with a small slot just big enough
for a electricians screwdriver to fit, I drilled a small hole in the back of the gauge so I could
do the adjustment with the gauge assembled and plugged in.
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