jumping rpm gauge

[the_GTI_new_guy]

My rpm gauge works most of the time normally, but sometimes it will get to say 3000rpm then blip to around 4000rpm. This then keeps blipping like this while the revs climb. Any idea on how i can sort this out? Cheers

[Gambit]

is it an 8v or 16v?

[Gambit]

reading from your other posts i realise its a 16v we're talking about. does this rev counter problem only happen when the car is really warm, i.e. been sitting in traffic etc? does it misfire/splutter/kangaroo also when this is happening?

[the_GTI_new_guy]

yes its 16v. The problem happens when car is at full operating temperature. It does it under normal driving, very little traffic, normally at 60-70 mph. The drive is perfectly fine, no problem except for the gauge. Its just a niggle really

[Gambit]

usually what causes that is the hall sender within the dizzy not functioning correctly

the hall sender sends a signal to the ECU so it can tell the coil to fire a spark, the coil also sends a signal to the rev counter - but usually you'll find the car will hesitate slightly as its not firing correctly - but you say that aint happening with yours

only thing you could try is work backwards from the dizzy, Ecu & coil cleaning up all the contacts

[the_GTI_new_guy]

Will try cleaning the contacts as the rides fine. Old car so corrosion of connects is likely i suppose.

[sco3y]

i had sort of the same problem,  rev counter kept ticking and jumping all over the place.
 it turned out to be the rev cable trapped under the air filter intake pipe.

[Gambit]

think thats the speedo cable your talkin about mate. the rev counter doesnt have a cable