Tach runs 2k RPM too high
04-12-2012, 12:58 AM
#4
AutoX
Thread Starter
Join Date: Mar 2012
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
On closer inspection it looks like more than my tach is off.
Tach - 2k RPM too high
Fuel - reads 1/4 tank when really over half
Speedometer - gauge reads about 10% - 12% low compared to the digital speed
Could this be electrical? Something else? This is my first Porsche 993 so would these these behaviours be considered 'normal' ?
Tach - 2k RPM too high
Fuel - reads 1/4 tank when really over half
Speedometer - gauge reads about 10% - 12% low compared to the digital speed
Could this be electrical? Something else? This is my first Porsche 993 so would these these behaviours be considered 'normal' ?
Last edited by DanV; 04-12-2012 at 12:59 AM. Reason: spelling
04-12-2012, 02:11 PM
#5
Rennlist Member
It might be as simple as dirty contacts on relay R11 .... see recent R11 cure thread. If not ....
AFAIK, all gauge sensor inputs are processed by a 'Central Informer' module ( likely an A/D converter), which then sends a signal to teach specific gauge.
With multiple errors, I would look there next: it is a cig. pack sized aluminium case tucked up under the dash .... and a PITA to access. firstly, unclip the two ribbon harness connectors & spray w. contact cleaner. If no go, it is possible moisture penetrated the module - tough to recover from that, so new part req'd..
Another
AFAIK, all gauge sensor inputs are processed by a 'Central Informer' module ( likely an A/D converter), which then sends a signal to teach specific gauge.
With multiple errors, I would look there next: it is a cig. pack sized aluminium case tucked up under the dash .... and a PITA to access. firstly, unclip the two ribbon harness connectors & spray w. contact cleaner. If no go, it is possible moisture penetrated the module - tough to recover from that, so new part req'd..
Another
08-13-2012, 10:44 AM
#7
AutoX
Thread Starter
Join Date: Mar 2012
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
I shelved this issue for a bit and put it on my 'winter fix it' list. I was driving this weekend and my tach needle got stuck at 5000 RPM. I tapped the glass face and the needle fell down into the tach. I think I've discovered the real issue. I can see that the needle has a post on it - is it just a matter of pulling out the gauge and reinserting the needle or has the post broken off?
I'm wondering now if one of the previous two owners replaced the gauge faces, as it might explain why the others seem to be off a bit. May be as simple as not having returned the needle to the correct positions.
I'm wondering now if one of the previous two owners replaced the gauge faces, as it might explain why the others seem to be off a bit. May be as simple as not having returned the needle to the correct positions.
