rev counter runs wild - false reading

[Chris5044]

intermitedly this happens .... I rev and its ok .. then as i pass through the range it sometimes jumps up and and goes past the actual rev range that the engine is doing

so its now giving me a red line .. but im probably only doing 5000rpms!!!

how do i fix this?

I have also recently done the plasma guage upgrade

[s2_bo]

This is a bit alarming Chris. i hope it will sort out.

Might just be lose connections at the back of the connector blocks??? just a thought.

Cheers.
Bo

[Chris5044]

not loose i checked ..... any ideas anyone? .. this started showing before the guages

.. its not all the time ..

anyone?

[Ross]

I've heard of issues with no RPM signal being sent, not sure what causes it or how it's resolevd, but maybe there's a failure of something in terms of a sensor? Sorry to be vague, just shooting out ideas here...

[Chris5044]

thats ok .. ill find it somehow

ps: ur videos up now from combe enjoy

[Chris M]

I thought i had this problem with my car, revs sometimes just drop off to 0 then jump back upto 1k, 2k etc.

Thought it was doing it on the way up too, Only realised the other day that i don't have a rev limiter / its not working all the time/ not there. as i hit the limiter in first then into second gear and the car pulled so strongly and kept pulling relentlessley past the 7500 RPM lines , at which point i promptly changed gear

Need to check the hall sendor on mine.

[Chris5044]

any thoughts guys .. as this is getting on my **** ... and ill be able to fix this soon as im finishing uni

[Chris5044]

bump ... any checks i should do?

[Acidburn]

Bump - I am also getting this now every so often, I can hold the revs and it will move slightly up and down and gives false redline readings. Any ideas?

[Welleh]

me too! no idea what it is, i though possibly dodgy grounding but havnt got round to checking it!

[Acidburn]

Seems like this might be getting a common problem, its just annoying as I keep thinking the engine's topped out when it has not.

[Ws2]

Me too, it happens more when it's cold or raining outside.

[kwlw]

Me too, it happens more when it's cold or raining outside.

I bet, that it is something broken/loose soldering inside the dash. Motronic ecu provides tachometer signal, so this eliminates sensor fault.

Sau

[Matt_D]

It must be an S2 thing as mine does this

Might be a problem with the feed, where it comes from i hav'nt got a clue some feeds are from the alternator but my voltage guage does'nt move when the rev counter flicks up and down, strange!

[Ws2]

I bet, that it is something broken/loose soldering inside the dash. Motronic ecu provides tachometer signal, so this eliminates sensor fault.

Sau

Yes, that's what I was thinking too.
I heard this (dash) problem is typical for the Audi b3/4 models, so I'm going to check the dash soon.