Toledo Rev Counter

[sassy_328]

Hi Guys, wondering if anyone could help me...

Got a 2002 1.9Tdi with an intermittent problem on the rev counter, it works perfectly for a while then goes mental, jumpin all over the place , erraticly moving around. So i am assuming as the engine is not revving erratically to match then its one of two problems; the needle itself (which i have been told will mean a whole new panel and an expensive bill) or the sensor somewhere on the engine or crankshaft? I can get the sensor from seat for about 30 quid, and want to see if its that before having to bite the bullet and get a new instrument panel. Trouble is, i dont know where to start! anyone know where it is and how easy it would be to change?

Any help greatly appreciated!! Cant believe it costs 70 quid to put the vag com on it!!

Cheers,

Ben

 

[Muttley]

The engine speed sensor picks up a signal from the edge of the flywheel on every rotation. It is on the front of the block, next to the gearbox flange.

However, I would bet it is not faulty. It feeds into the ECU, and the tacho signal is sent from the ECU to the instrument panel processor. If the sensor were faulty it would show up as erratic idling or dropping into a limp mode. If I had to guess it would be a wiring harness fault or the tacho itself.

 

[Deleted member 5241]

Wiring fault here too, does it do it on certain corners or after going over bumps??? Try whacking the top of the dash to stop it.

 

[sassy_328]

I commute to work every day, about a 40 min drive. As soon as i come off the motorway doing a steady 85 at about 3k revs, then i come to the roundabout, change gear, and it might go limp or go to say 4k and idle there, if it idles at say 4k it will act completely normal, but be 4k too much! If it goes limp, sometimes when i switch off the car then turn it back on again it might go all the way back round to 0 and then work completely normal.

I have not noticed it stop working when i go round corners or over bumps.

I have checked the wiring harnesses on every sensor on the engine, they all seem fine, as the problem is intermittent do you suggest opening the ECU and checking harnesses there?

...got a feeling its the needle though.

Thanks for your help guys, much appreciated.

 

[Muttley]

sassy_328 wrote

I commute to work every day, about a 40 min drive. As soon as i come off the motorway doing a steady 85 at about 3k revs, then i come to the roundabout, change gear, and it might go limp or go to say 4k and idle there, if it idles at say 4k it will act completely normal, but be 4k too much! If it goes limp, sometimes when i switch off the car then turn it back on again it might go all the way back round to 0 and then work completely normal.

If I understand this correctly, you are saying that the engine behaves normally but the tacho indicates zero revs (it might go limp) or +4K revs (go to say 4k and idle there). This certainly indicates a fault with the dashboard processor, part of the instrument cluster. If on the other hand the engine is going limp or idling at 4K then the engine speed sensor should be checked. In either case, find someone near you with VAG-com who can help you read the fault codes - there is a register on this site, I think?

I have checked the wiring harnesses on every sensor on the engine, they all seem fine, as the problem is intermittent do you suggest opening the ECU and checking harnesses there?

Certainly not, there is nothing inside the ECU that you or I can test and opening it will create problems if you later have to put it in for service: the reaction might well be opened ECU=chipped.

It might just be worthwhile disconnecting the ECU, checking for any obvious signs of corrosion, wear or damage to the connector, treating it with contact cleaner and reconnecting it.

 

[sassy_328]

Cheers Muttley, much appreciated. I will do that.