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> Speedometer, Reading about 10mph too fast
iansale
post Jun 30 2003, 01:08 AM
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My tires and wheels are stock size. The tranny is a side-shift conversion. The speedometer is a 120mph VDO (I have no reason to believe that it isn't the original).

When my speedometer reads 60mph, I'm actually doing closer to 52mph. It's a little tough to tell if it's off by a consistent percentage at all speeds or if it gets worse the higher the speed, but...

Any ideas as to what could cause this?


Oh… one more thing… the little knob below the dash… it’s meant to reset the trip odometer, right? Mine will spin the trip odometer and the odometer. I’m I correct that the odometer is malfunctioning? (Anyone want to buy a 914 with let's make it 34,000 original miles? (IMG:style_emoticons/default/cool.gif) )
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madd_dogg_914
post Jun 30 2003, 09:03 AM
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I have read before that the early Porsches (including our beloved teeners) didn't exactly have the most accurate guages. In fact I just read an article that said at 70MPH, actual speed was 62 MPH. This was a Car and Driver, or Road and Track I forget which. They said in such an expensive car they should have more accurate guages. I believe your speedometer is working good, mine shows about the same discrepency. I just live with it and I can ALWAYS speed and I never get a ticket (IMG:style_emoticons/default/wink.gif)

-Chris
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Jeffs9146
post Jun 30 2003, 04:35 PM
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You can have it calibrated! I did mine in Hollywood and it cost me about $50

Jeff
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Dave_Darling
post Jun 30 2003, 04:42 PM
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The speedometers weren't the most accurate in the world--in fact, Porsche at that time was pretty notorious for having "optimistic" speedometers. The're now required by TUV (I think) to read not more than a certain percentage over--and never under.

The odometer mechanism in your speedo is failing. You can send it out to have it fixed (and can probably have it recalibrated while you're at it) or you can DIY. There are tech articles on Pelican's pages and on Tim's 914 Fan Page about fixing the odometer.

--DD
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dagdal1967
post Jun 30 2003, 05:38 PM
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Funny, My odometer and Spedo are doing almost exactly the same thing.

Spedo is about 5-9 miles Slow and the Odometer doesn't work at all.. When I use the Trip Reset knob, every time I advance the Trip to 0, it advances the Odometer by 1 mile..

Hmmm.

Where did you say those DIY ODO re-build articles were, Dave???

Thanks

Doug
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Lawrence
post Jun 30 2003, 08:59 PM
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Mine is doing the same thing. I'm going to have it recalibrated when I get the entire set refurbished and newly silk screened.

I keep a GPS in the 914 so I can know exactly how far over the speed limit I am. (IMG:style_emoticons/default/rolleyes.gif)

-Rusty (IMG:style_emoticons/default/smoke.gif)
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Dave_Darling
post Jul 1 2003, 03:35 PM
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QUOTE(dagdal1967 @ Jun 30 2003, 03:38 PM)
Where did you say those DIY ODO re-build articles were, Dave???

http://www.pelicanparts.com/techarticles/M...auge_repair.htm

http://www.914fan.net/speedo.html

--DD
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tat2dphreak
post Jul 1 2003, 03:41 PM
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mine seems pretty close(checked with someone following me)... while accellerating! however, when I decel it hangs at 60,70 (whatever highway speed I'm going) and then drops sudenly when I get to about 35 mph.... (IMG:style_emoticons/default/confused24.gif)

any idea what causes this?


(IMG:style_emoticons/default/beer3.gif)

also, is there no reset switch on the trip ODO?
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Aaron Cox
post Jul 1 2003, 03:44 PM
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something about the cable sticking to its sheath.....and then all of a sudden breaks free from the 'torque-ing' effect.....

i read this somewhere about VDO speedos
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elmonte
post Jul 1 2003, 03:44 PM
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QUOTE(tat2dphreak @ Jul 1 2003, 02:41 PM)
mine seems pretty close(checked with someone following me)... while accellerating! however, when I decel it hangs at 60,70 (whatever highway speed I'm going) and then drops sudenly when I get to about 35 mph.... (IMG:style_emoticons/default/confused24.gif)

any idea what causes this?


(IMG:style_emoticons/default/beer3.gif)

also, is there no reset switch on the trip ODO?

Under the dash above your right knee
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Dave_Darling
post Jul 1 2003, 03:46 PM
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Probably the needle itself is sticking. You might be able to clean it all up if you took it apart? Might fix it. I've also heard of the glass being installed wrong (it was slightly concave and should have been installed convex) and that causing a sticking needle.

The reset is at the bottom of the dash. There should be a small knob that you turn to reset the trip odometer. The knob is at the end of a short piece of cable that plugs into the back of the speedo.

--DD
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tat2dphreak
post Jul 1 2003, 03:52 PM
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DOH! I guess I *might* have found it if I'd looked first... but it wasn't obvious...

I haven't bothered cleaning the gauge since this is the car I'm going to pillage for parts before too long...
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