# Speedo and tach WAYYYY off...



## billye74 (Apr 22, 2016)

I have a 2010 Nissan Altima 3.5 SR that I just purchased with 77k miles on it...

The only issue with the car is the speedo and tach are WAYYYY off... like 30 mph off!!! And the RPM needle does not go past 1200 or so... 

The odd part is that the trip computer for Avg MPG and Avg MPH is dead on accurate... well at least the MPH portion...  *I set the cruise and re-set the trip computer and it said I was @ Avg MPH 66.0 and I passed one of those road side speed display warning machines and it flashed 66...

Everything else works... all other gauges, turn signals, 4 way flashers, etc... 

Any idea on what needs to be fixed or replaced?

I did notice that there are Infiniti wheels on the car, NOT Nissan wheels, if that matters at all... ???

Thanks in advance,

Billy


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## SPEEDO (Jun 9, 2003)

I don't think the tire/wheel size would throw it off by 30mph, pretty sure stock tire size is 215/55/17, what size do you have on it? I would lean towards a speedo cluster issue, speedo sensor?


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## billye74 (Apr 22, 2016)

Its the 215/55/17's... 

I don't know enough but if the sensor was bad, wouldn't it send bad info to the computer that in turn calculates Avg MPH... its puzzling that part is correct but the needles for the Tach and Speedo are that much off kilter...


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## OhmsLaw (Mar 29, 2016)

billye74 said:


> the RPM needle does not go past 1200 or so...


Does it read accurately at idle?

Average MPH is just distance/time. Is the odometer accurate?

If both are electronic (vs. drag cup type) you'll need an oscilloscope to troubleshoot this one.


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## billye74 (Apr 22, 2016)

I actually started it up earlier and the tach was 100% accurate but after a few minutes it was like it was getting lazy / losing its prime and was falling back down out of range... *maybe I need to drop a Viagra in the gas tank... LOL

However, the red needle for the speedometer is way below "0" as its starting point... 

The odometer is 100% accurate...


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## OhmsLaw (Mar 29, 2016)

billye74 said:


> I actually started it up earlier and the tach was 100% accurate but after a few minutes it was like it was getting lazy / losing its prime and was falling back down out of range... *maybe I need to drop a Viagra in the gas tank... LOL
> 
> However, the red needle for the speedometer is way below "0" as its starting point...
> 
> The odometer is 100% accurate...


Tach needle intermittently slips relative to mounting shaft (but how does it reset itself)? Needs glue.

Speedo needle needs to be repositioned to zero when at 0 MPH, and then glued. It's an "offset" problem
http://www.google.com/search?client=safari&rls=en&q=gain+offset&ie=UTF-8&oe=UTF-8

Inaccuracy at high speed is a "gain" problem.

Pulling a dash cluster is a bit of work. Disconnect the battery B4 starting.


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## ChandlerAZ (Aug 26, 2011)

This might sound stupid, but I had something similar happen to me. I had a headlamp burn out, and after replacing it, it was still out, so I checked the fuses and had a burned fuse. I replaced it, and so later when I had a burned out headlamp again, I checked my fuses and it actually turned out to just be a burned out headlamp that time, but then I had a new electrical gremlin. After about a month of turn signals not showing in the car, and the cluster acting weird, I took it to the stealership where they wanted to replace the whole cluster. I told them I'd think about it, took it home and checked the fuses one more time, and I found I'd accidentally placed a fuse in the wrong spot, and on correcting the issue, my cluster started working just fine again. It's worth a look, and best of all, it's free to do.


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## smj999smj (Jan 1, 2006)

The cluster is an integrated meter assembly. It's possible that the cluster is the problem, as it's a fairly common occurrence. I wouldn't recommend disassembling it. If the cluster is faulty, the best thing to do is remove the assembly and send it to a company that repairs instrument clusters. A simply Google search will pull up several places that do such


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