Speedometer removal

[Doc308]

I just bought a '92 and the previous owner had to replace the speeometer. He got a used one , which reads 14k miles lower than the actual miles. I want to remove it and have it calibrated to reflect the actual miles. Can anyone give me a step-by-step instruction on how to remve the speedo? Are there any particular pitfalls to be wary of ?

Hmm--in another thread I reported that the coolant temp guage also misreads. I wonder if the wires to that gauge were affcted when the speedo was replaced. So, how do I remove that gauge also?

Finally--does anyone know of a good speedo shop which could do this. My local dealer was of no help with this.

Thanks in advance, comrades.

 

[CDX_NSX]

You can download the Service Manual. The instructions begin at page 23-128.

 

[drew]

First we need to define terms, you are all over the map:

I think you mean odometer, it is the counter that records the total distance driven.

A speedometer is something that registers the rate of travel over time.

Calibration of the odometer is probably not want you want, that would just insure that it will record future distance travelled accurately. I think, you just want the odometer to be ajusted to accurately reflect true distance driven with the car.

And when you say "new one", do you mean an entire instrument cluster?

I would suspect that no legitimate shop would modify the odometer, it is a Federal felony in most cases. Just not worth it, because they don't know your intentions...despite the fact that you want to roll-forward value of the odometer.

So you will probably have to do it yourself. Two ways that I can think of doing it.
1. Adapt a drill to turn your speed sensor and just let it run until you get to your appropriate odometer reading. Probably take a couple of weekends and a battery tender to do it...100MPH x 140 hours?

2. Remove the cluster and disassemble. very carefully remove the odometer and reassemble it with the proper reading on it. This will probably be fairly difficult as I would think it is not made to be removed (ever) and will require small precise tools.

And legal disclaimer: it is a felony not to disclose the fact that the odometer has been tampered with or modified.

Good Luck

Drew

 

[Tony Montoya]

How do you know the odometer is 14k off the actual mileage? Is it supported by service records?
I had a Toyota odometer that failed inside of 3 years so Toyota replaced it and made a note of it. The new one started at zero. The one bad thing was the owner of the car when it failed probably drove the car 20k km before mentioning the failure to Toyota. When I bought the car none of those details were mentioned to me but I didn't know what a 20k mileage car should look like vs a 34k + whatever the owner drove with no odo. I got ripped off because I didn't ask for complete records.
Now it's the law for owners to declare the mileage.

We still own the Toyota and it has gone 200k.

 

[Doc308]

Drew--from your description, it sounds like the odometer on these cars is a separate gauge from the speedometer. Is that correct? The previous owner told me that he had to replace the speedometer and that that is why the odometer is off. Does this make sense?

 

[Doc308]

Tony--the milage is verified by service records and Car Fax.

Drew--another Q, if you don't mind. Where is the speed sensor located?

 

[drew]

The speedometer and odometer are seperate. The speedometer can be replaced, the odometer is clipped into the cluster "chassis".

The cluster is sensitive to no properly screwing down the fasteners in the back and causing a bad connection...might be your problem---dunno.

The speed sensor is located on the transmission.

However (just thought of this), what might be easiest over all is to get a signal generator to mimic the output from the speed sensor. It is a basic square wave as specified by the manual. Just use some clips and hook it up...

Some guy even tells you how to build your own signal generator here

Drew

 

[Doc308]

Drew--thank you, again. You seem to be a fountain of knowledge ( compared to me anyway) ! Do you know if a signal generator unit can be purchased at a place such as Radio Shack . I checked the site you referred me to and I don't think I trust my own skill level to build one myself.

 

[drew]

Signal generators are easily found on ebay.

You are probably the only person to do something like this, so you will have to make sure you do it right.

Make sure you match the expected power and frequency values that is within spec of the speed sensor. Clip it into the a speed sensor, turn the key on and your car should think that you are moving.

Probably have to disable TCS too.

This is just a suggestion, I am assuming no liability. But it seems reasonable that it should work just fine...

Drew