wrong rpm?

[aga]

hey guys, a question! (no shit!) my car's rpm gauge (the dash one) started showing 500-1000 rpm more than real. i see on my commander that i have for example 1000rpm idle, and the dash says 2000...besides i can tell by the sound too. it happened before for a trip then straightened itself out. now here it is again. is it a cable , somewhere rubbing or something? i guess ecu to dash?

[brndck]

its not a mechanical tach. the instrument cluster gets a signal from the ecu.
the ecu gets a signal from the distributor if you have a KA, but seeing as you're in greece you probably have a CA or SR? the SR and CA use a cam angle sensor (cas).

are you using a power fc?

[aga]

i have an s14 sr , with powerfc. by cable, i meant electrical cable. (you're used to calling them wires, sorry)

[Sileighty_85]

Probably the gauge itself. Pretty common for S14s to do that.

You can reflow the solder points on the back of the gauge that the screw go into in hopes that fixes it.

[aga]

so , a broken soldering point could be the cause? i'll check it.

[aga]

driving home today i noticed a method to this madness...

the gauge rpm are twice the real ones!

1000 rpm = 2000rpm

3000, = 6000

my car is learning multiplication tables it seems.

[zerodameaon]

my car is learning multiplication tables it seems.

Hopefully it does not achieve sentience anytime soon.

Sileighty_85 knows his stuff here, he pretty much started the discussion on Zilvia of fixing the issue rather then replacing the tach.

[aga]

Hopefully it does not achieve sentience anytime soon.

if it does , its gonna thank me for saving her from the previous owner. yeah its certainly something wire-related, im gonna look into it after work, if they let me leave some decent hour...

[coupesallday!]

I tried soldering mine and it does not work. My gauge is still at 2k everytime I turn my car on instead of 1k but it's not really that high.

[aga]

i removed the dash and resoldered everything behind the gauge.

i would say it did SOME difference,but not fixed it. now it sometimes works fine, sometimes x2 and sometimes something in between. i've noticed it jumping around while sitting at a traffic light. there's a big resistance behind the gauge, could it be knackered? should i try to replace that one? if that doesnt work i'm tossing it and replace it with a Koso motorcycle thingy, my mate's got one and it's excellent

http://www.itibitismart.com/photos/itibiti/wish_list/koso_speedo/koso_speedo_004.jpg

[aga]

found the cause of my woes. there's a plug near the ecu at the passenger footwell that was loose. when you wiggle that, the rpm's bounce all over the place. tie wrap remedy, all ok. :D

[Ayy_mo]

glad to hear