Rev counter not working properly? Any ideas

[mk1chopper]

The 318is i will be getting has some minor problems, but nothing major (i hope, well its got 12 months mot and 6 months tax so not all bad) I just been informed by the owner that the rev counter is playing up, it works fine up but wont go over 4500 rpm, is this a sign that the batterys on the dash board need chaning or could it be something else. Also he's said that the heater in the car is decidedly poor, any idea why this could be? is it expensive to fix?

Thanks for any help Chris

[DazzyA]

I've seen this problem before on another thread, do a search, I seem to remember that may be limited, but don't quote me on that.

[stuartgallafant]

i had this problem before. its basically got an instrument cluster from a 6 cylinder car in it.

the rev counter is displayed by something in the cluster receiving pulse signals from the DME, when the engine sparks on a cylinder(1 i think).

if you put the clocks from a 6 cyl car into 4 cyl car, it gets confused. you may possibly notice that your petrol guage reading is incorrect (it is with mine)

i think though, that you can overcome this porblem by removing the coding plug from your 4cyl cluster and placing it in the other cluster.

the coding plug is the small little box of tricks, located in the bottom right hand corner of the instrument cluster. you must change this with the ignition off.

if this is not the problem, then im not sure what to do, as i've never had anything else go wrong other than that scenario

let us know hoiw you get on...

as far as the heater goes, it could be a few things:
-blocked heater matrix
-air lock in the cooling system
-thermostat
-freyed heater cables

time to get your diagnosis hat on mate!!!