Terrano rev counter swings wildly (or not at all)

[slack]

Hi. I've just bought a 93 auto diesel Terrano.

Most of the time the rev counter doesn't move at all (sits on zero), but sometimes it will just start swinging wildly all over the place. It does this both when driving and when the engine isn't running (like when waiting for the glow plugs). Occasionally after driving for about an hour it will work normally for a while.

I don't think this is the common "bent needle" problem, seems more like wiring or computer.

???

[phaedrus]

Hello.

I'm sorry I can't tell you about any specific common problems with this vehicle but certainly wiring and connectors would be the predominant issue with these sorts of things.

Given that the wiring between the body and motor, and associated connectors, suffers the most movement and vibration this is where I'd start. It's a no-cost check just to follow the cable from the rpm sensor (I think around the gear drive to the injector pump for your model - someone else may have one, or know off hand, to confirm) and see if there are any loose or frayed connections/wires. If you were careful and used a mirror or someone in the vehicle with the engine running and manipulated the cable/connectors you might be able to see from that if there's a fault in the line somewhere if the tacho flickers in and out of life.

Failing that then it could be connections/wiring in the cab or the tacho itself - you could pull the instrument assembly out and remove the tacho to closely inspect and ensure the needle isn't bent and jamming on the face... IMO it's unlikely to be the ECU.

Cheers, P.

[icekayak]

Funny you mention it. My terrano suddenly started doing this last week... Haven't worked out why yet, but let me know if you work it out. Cheers

[wax]

The needle has bent and its hitting the backing plate. Its a common issue in australia I didnt think it would happen in new zealand as it caused by the heat of the sun wilting them

[will i am]

as above. happened to both my terranos. pull speedo cluster out. pull rev or/and speedo needles off and put them in hot water while bending them the other way.

[MK1TNA]

Ha I just drove a mates pulsar thismorning and its revometer was doing the same dancing all over the place, must be a nissan thing

[RJT]

My '92 Terrano does this on it's speedo (and very seldomly rev counter). I've noticed that it's worse on warm/hot days. Though I know mine's definately bent needles. It gets stuck on 40 and 80km/h. Doesn't worry me though, I just use the GPS as my speedo
Also every now and then I jump in to start it up and find the revs at 4000 RPM

[slack]

Interesting... thanks for the suggestions. I'll have a look at the needles when I get a chance and then maybe try to find the rpm sensor and wires