speedometer bounces around occasionally under hard acceleration

[e.pie]

is there anything that would cause that other than the speed sensor starting to go bad?

just making sure before I order one

[Honcho]

I just had this issue. 99% it is the sensor. The only other cause could be a loose connection either at the sensor plug or gauge cluster plug. I replaced my sensor this weekend and it fixed the problem.

[Rob4092xx]

Do not, I repeat, do not replace your speedometer unless absolutely necessary.

The value of your car will plummet if the speedometer is changed from original!

Other that blowing the engine, I can't think of anything else that will de-value your car as much as changing the speedo!

I just had this issue. 99% it is the sensor. The only other cause could be a loose connection either at the sensor plug or gauge cluster plug. I replaced my sensor this weekend and it fixed the problem.

[Honcho]

Rob, I am talking about the speed sensor that is on the transmission, not the gauge itself.

[Rob4092xx]

Whew...that makes me feel a lot better.

I had to replace a speedometer on my wife's car several years ago and I couldn't give it away when I went to trade it in. Horrible experience!

Rob, I am talking about the speed sensor that is on the transmission, not the gauge itself.

[sduffass]

Bumping this thread up since I believe I have this problem.

Symptoms.
1. After longer drives. Like 2+ hot long drives my speedo starts bouncing up and down. It will read true for a second, then go back down to 0, then jump back up to the true speed and then back to 0. During the time it's at 0 it doesn't record my miles. Not like it matters to much since this is only the 3rd time it's happened and I don't drive THAT much.

2. My AEM gauge also shows mph under a setting "U55" and that setting shows up true weather the stock speedo gauge works or not, but it has happened before where the AEM gauge shows 0 as well but that's not always true. The last time it happened the AEM gauge read true and stock one was bounching up and down, but the first time it happened both were acting funky.

Is it just the sensor that needs replacing then or is it something deeper? Also where's it located?

[pgilliam1]

Bumping this thread up since I believe I have this problem.

Symptoms.
1. After longer drives. Like 2+ hot long drives my speedo starts bouncing up and down. It will read true for a second, then go back down to 0, then jump back up to the true speed and then back to 0. During the time it's at 0 it doesn't record my miles. Not like it matters to much since this is only the 3rd time it's happened and I don't drive THAT much.

2. My AEM gauge also shows mph under a setting "U55" and that setting shows up true weather the stock speedo gauge works or not, but it has happened before where the AEM gauge shows 0 as well but that's not always true. The last time it happened the AEM gauge read true and stock one was bounching up and down, but the first time it happened both were acting funky.

Is it just the sensor that needs replacing then or is it something deeper? Also where's it located?

Heat does affect this sensor. Mine would not act up until the 4th track lap and would act normal after the engine cooled down. The sensor is located on the top of the tranny to the rear. It has wires (2 - I think) coming from the harness with a plug on the top and a small heat shield around it. I think it's mounted with 2 10mm bolts. These sensors are sold cheaply on eBay and the quality was good. You can use either type (they're listed different for different model years but both work well with no modifications necessary except moving the plug off the mounting - the wiring from the harness is plenty long). This should fix your problem. Fairly easy DIY.

[sduffass]

Heat does affect this sensor. Mine would not act up until the 4th track lap and would act normal after the engine cooled down. The sensor is located on the top of the tranny to the rear. It has wires (2 - I think) coming from the harness with a plug on the top and a small heat shield around it. I think it's mounted with 2 10mm bolts. These sensors are sold cheaply on eBay and the quality was good. You can use either type (they're listed different for different model years but both work well with no modifications necessary except moving the plug off the mounting - the wiring from the harness is plenty long). This should fix your problem. Fairly easy DIY.

Cool

So any of these $10 ones work then?

http://www.ebay.com/sch/i.html?_trks...ensor&_sacat=0

[pgilliam1]

Yes. Any sensor that fits an NSX, regaurdless of model year will work. the only difference is that the early model years have a wire pigtail hardwired into the sensor. The later models (as in the pictures) just have a plug recptacle on top of the sensor. The plug from the wiring harness is the same so it fits either sensor.

[Keahistight]

That happened to me too then the spedo just went dead. My issue was the wire on the plug in the engine bay. Super easy fix you can do yourself for $0.

[sduffass]

If anyone has a picture of the location feel free to post it up. I'd appreciate it.

[Alec_fields]

I'm also having the issue. I guess this 100+ degree weather takes its toll on the speed sensor! I would also like to see where this is located. Also a question for anyone who has done it, how much of a pain in the A$$ is it to change?

[comtec]

If anyone has a picture of the location feel free to post it up. I'd appreciate it.

Best i can do this far from home.

Mike

[Alec_fields]

Awesome! Thanks a lot! I'll have this problem nipped real quick!

[chrisbailey13]

I'm also having the issue. I guess this 100+ degree weather takes its toll on the speed sensor! I would also like to see where this is located. Also a question for anyone who has done it, how much of a pain in the A$$ is it to change?

Its super easy to fix...2 bolts and its done.

[Alec_fields]

Are they different for a 91' vs. 92'+?......never mind, I see it above. Look and you shall receive.

[angus]

Whew...that makes me feel a lot better.

I had to replace a speedometer on my wife's car several years ago and I couldn't give it away when I went to trade it in. Horrible experience!

Actually, the NSX speedometer is not connected to the odometer - you can change it without altering or tampering with the mileage reading.

Also if you ever do have to change the speedo on a car that does have a built-in ODO - just make sure you get one of equal or HIGHER miles - then no problem.

[sduffass]

Bumping this up again.

So if you buy a sensor WITHOUT the plug then you'll have to cut and splice wires then? Correct me if I'm wrong.

[sduffass]

Yes. Any sensor that fits an NSX, regaurdless of model year will work. the only difference is that the early model years have a wire pigtail hardwired into the sensor. The later models (as in the pictures) just have a plug recptacle on top of the sensor. The plug from the wiring harness is the same so it fits either sensor.

Nevermind, Just reread that.

[Alec_fields]

I just did the replacement on my 91' last week. The hardest part was getting more than one hand down there to do the work. The sensor with the plug on top that I used from eBay and pai $7 for works perfectly. It did make me very nervous when I saw that it was different from the one that was in my car though. Glad it was a simple fix. I was freaking out.

[bngl3rt]

Hmm, I am getting a tach bounce... Could my fix be similar? Where is the sensor that drives the tach?

[sduffass]

I can't wait to get this stupid sensor. I was racing a motorcycle the other night and my "2 step" kicked in because my speedo was reading 0.

Anyways I'm hoping it's the sensor that's making it kick in

[comtec]

Hmm, I am getting a tach bounce... Could my fix be similar? Where is the sensor that drives the tach?

The ECM (engine control module) operates the Tach. Does it just bounce at idle?

Mike

[Briank]

Hmm, I am getting a tach bounce... Could my fix be similar? Where is the sensor that drives the tach?

I have see a couple of those and there may be a problem on the gauge cluster circuit board. The amps and the ccu are not the only place on the NSX that has bad capacitors.

[bngl3rt]

I have see a couple of those and there may be a problem on the gauge cluster circuit board. The amps and the ccu are not the only place on the NSX that has bad capacitors.

How do you check for bad caps? Can it be done visually or with a voltmeter? If there's a problem I'd love to take it out and send it your way, but I doubt the car will start with the odometer disconnected (or even if it did, that would be dishonest...)