Crazy Tach

9

92 LX

Member

Nov 10, 2004

78

0

7

Mar 21, 2012

#1

• Mar 21, 2012

• #1

Would any of you guys know why my tachometer reads 2700 rpm when my engine is idling at 900? On the way home today, it stayed there, then revved up to about 4gs while I was accelerating (5 spd) then after I shifted, it went back to 2700. It dropped back to normal right before I got home, and behaved after that. I'm thinking a loose connection (or maybe a ground) but any idea where to check? The engine runs fine, but this is annoying. It just started today. Anybody?
'92 LX 5.0 5 spd

 

Noobz347

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#2

• Mar 21, 2012

• #2

OEM tach?

Any ignition system mods?

 

wythors

Get off my lawn!!!

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May 17, 2000

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Mar 21, 2012

#3

• Mar 21, 2012

• #3

This is actually a fairly common problem that I've never found a fix for. My wife's car started doing that right after we got it. I scoured the 'net and couldn't find anyone that had fixed the problem. I checked all the connections. I paid for a couple of hours of diagnosis at my local Mustang shop. Nothing. I replaced the tach and no more problems. Since I have three Foxes, the next time I was at the bone yard I spent $20 and bought an extra cluster to have a backup.

 

9

92 LX

Member

Nov 10, 2004

78

0

7

Mar 21, 2012

#4

• Mar 21, 2012

• #4

Yes, factory tach. Only an aftermarket coil.

 

9

92 LX

Member

Nov 10, 2004

78

0

7

Mar 21, 2012

#5

• Mar 21, 2012

• #5

Hmmm,
A buddy of mine has an extra cluster. Maybe I can snag the tach from him. Still I'd like to try and fix mine. Seems the gremlins are appearing as she's getting old.
twenty this year as a matter of fact. I'm going to have to post a pic to replace the "?" now that she's gotten a much deserved facelift. Nice Calypso green Wythors. I ALMOST bought a '92 Calypso green vert. instead of my Emerald Green hatch. The hatch had too many more mods, and $3k less.

 

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor

Admin Dude

Jan 4, 1985

42,912

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Box behind Walmart

Mar 21, 2012

#6

• Mar 21, 2012

• #6

92 LX said:

Hmmm,
A buddy of mine has an extra cluster. Maybe I can snag the tach from him. Still I'd like to try and fix mine. Seems the gremlins are appearing as she's getting old.
twenty this year as a matter of fact. I'm going to have to post a pic to replace the "?" now that she's gotten a much deserved facelift. Nice Calypso green Wythors. I ALMOST bought a '92 Calypso green vert. instead of my Emerald Green hatch. The hatch had too many more mods, and $3k less.

Click to expand...

If you plug in the other OEM tach and the problem goes away then I'd say reviving yours would likely be cost prohibitive.

 

9

92 LX

Member

Nov 10, 2004

78

0

7

Mar 21, 2012

#7

• Mar 21, 2012

• #7

Yea, I agree. I was hoping somebody would know where the ground was so I could just check that first, but I guess you already went thru that. Thanks for the tip. You guys (this forum) are the greatest.