Scirocco rev counter only goes to 2500rpm...

[joshwa]

Hi,

Anyone know what could be wrong with the rev counter? It goes up to 2500rpm, sometimes 3000rpm, even though the engine is definitely revving further...

I've looked in the Haynes manual and it mentions the speedo cable - is this the same as the rev counter?

It looks like it might have had after-market dials put on?

Josh

[Tumble]

I think it's a similar sort of system to the speedo. Sounds like there's a bit of crubbish in the cable outer to be cleared out...

[joshwa]

So I guess I need to take it apart and have a gander

[SilentDeath]

strange, might also be the wrong clock in there? I know a lot of people tryed to put rev counters in fiestas that didn't have them as standard, and some use a different ratio.

[herulach]

should the rev counter top out at c.5k? it may be instruments from a v6 in a four pot.

[joshwa]

It still seems to idle around 1000rpm ? I think the rev counter should go to around 6 - 7000rpm.
I tried to take it apart but got nowhere :/

Found 2 wires in the engine that are disconnected, one is an earth lead, another is for the cold start on the injection unit apparently (according to the vague haynes manual pictures)... reconnected one successfully, the other will need a bit more work to reconnect. Will give this another go tomorrow and have another try.

Cheers,

Josh

[herulach]

Odd, perhaps its mechanical, can you get the dial out and maybe give it a wiggle/clean?

[Tumble]

You really need to get into the back of the clocks. The speedo/tacho usually come off the gearbox, which iirc on a VW is on the right side of the engine towards the bottom of the bay looking at it from the front

[joshwa]

Had another look, I think I've reconnected the cold start valve earth ok, and auxilary air valve ok, but the wires for both of these things are pretty dodgy / old / decrepid. (it shouldn't really matter as these are to do with the car starting / running when the car is cold).

I checked the alternator and cleaned that where the wires connect, but they all appear fine.

I've also thoroughly cleaned the ignition coil and all the wires connected to that - some of them were filthy and the metal was coppery looking! I haven't tried it yet as it's getting a bit late, but I'll try it again tomorrow.

[joshwa]

Originally Posted by joshwa

Had another look, I think I've reconnected the cold start valve earth ok, and auxilary air valve ok, but the wires for both of these things are pretty dodgy / old / decrepid. (it shouldn't really matter as these are to do with the car starting / running when the car is cold).

I checked the alternator and cleaned that where the wires connect, but they all appear fine.

I've also thoroughly cleaned the ignition coil and all the wires connected to that - some of them were filthy and the metal was coppery looking! I haven't tried it yet as it's getting a bit late, but I'll try it again tomorrow.

None of this helped

I've changed the air filter, the oil, and oil filter as well now, (with an oil flush in between)

and the rev counter will go up to 3000rpm quite freely now, and occassionally jump up to 4000rpm

Maybe I should spray everything with WD40

the only thing that I think might be wrong is that the alternator makes a sort of whistley / whiney sound all the time...

car performance seems great though

[SilentDeath]

drive belt might be worth replacing.. but not related..

the rev clock is usually fed from the distributor if it has one.. The speedo would be fed from the gearbox.

[joshwa]

I think it's probably the dials - as they appear to have been replaced with white dials - I've put a bid on some on ebay so hopefully I'll be able to get some new ones. The distributor looks okay (fairly new anyway), but I'll check it later.

[joshwa]

I've replaced the spark plugs (they were quite dirty (pic here) the one on the left, I spilt oil on yesterday)

And cleaned the dizzy cap but it's still the same, display only goes to 3k rpm

[joshwa]

Well - today - I took the car for a longer drive and after a while the rev counter seemed to go upto 4000, then on a more "spirited" drive it went up all the way to 6000rpm fairly smoothly... so it seems to have resolved itself.