Inaccurate spedometer

[Morthane]

I have an '86 DX, Automatic with A/C, no mods. My spedometer reads 5-10mph high at speeds over 40mph or so. I have the right sized tires, rims are stock, and the only person who owned it before me was a little old lady. Is this problem fixable?

[AccordNut]

does it rest at 0 when you're not moving? i guess it does since you didnt say otherwise...i dont think its fixable really, you could always replace it but thats a bit of a hassle especially trying to get the right mileage on the new speedo. maybe you need a new speedo cable? thats all i can think of

[AZmike]

Mine always reads 10% high and my tires are slightly oversized. I'm not sure if it's fixable, but it's definitely common.

[Morthane]

It sits at zero. My friend says "it might be a dirty wheel speed sensor", and I have the bad mother Hayes manual to look at that should there be one/where it is/how to do it. Just trying to get the ball rolling while I read the big gray book.

[Moodybluesr]

There is no "wheel speed sensor" as the speedometer runs off a cable that connects directly to the transmission. You could try pulling the speedometer cable, pulling it out of its housing and lubing it.

[newaccorddriver]

There is no "wheel speed sensor" as the speedometer runs off a cable that connects directly to the transmission. You could try pulling the speedometer cable, pulling it out of its housing and lubing it.


how does the speedo work then? i thought was only the odometer that connected straight to the transmission

[Moodybluesr]

The odometer and speedometer run off the same cable.

[newaccorddriver]

one other thing about tihs, since i have an auto in my exi, what happens when i change it to a standard from a carbed engine?

would the speedo read correctly and would the odometer read correctly because i read that those 2 things would be hooked up to the drive axles or the final gears

[Morthane]

Ok, decided to get off my butt and consult Hayes. Here's the results:

Hayes is very light in regard to the speed sensing equipment. Usually, there is inspections and testing, full removal and reinstallation, pictures, etc. In this instance, however, there isn't a whole lot - some pictures, no inspection, some replacement.

The speedometer and odometer is a single part that includes a speed sensor and pulser.

The speedometer cable connects to the spedometer (duh)

the other end of the speedometer connects to the speed sensor

The speed sensor is mounted to the transmission housing. There is the speedometer cable and two other hoses that connect to the sensor. The unit looks like a round disc with a cylinder that extends down the bottom of it with a gear near the end. Looking at the picture of it, it reminds me of a hockey puck with a drill bit on the bottom that might be used for going through rock.

I haven't been able to discuss this issue with a licensed mechanic yet, but I did research part prices (prices were found at a Honda dealership, all prices are US dollars):

Speedometer cable: $55
Speed Sensor: $220

[FyreDaug]

I have a similar problem, I have GPS hooked up to the computer system in my car and it gives speed readouts. At 50kmh on speedo, it reads 48 on gps. 60 speedo is 56, 80 speedo is 76 and 120speedo is 112. I did these tests yesterday. It does rest at 0, there are the 2 dashes for 0 and 10? side by side, it rests on the higher one. I can usually trust it for accuracy in city but not so much highway.

185/70/13 on the front and 175/80/13 on the back (junkyard tires, all they had for 15 bucks to fit on my honda) but my parts car has some tires I need to swap later, but its not too much of a concern.

[mkymonkey]

HOORAAAY old thread revival!!


ok guys, i have a friend that has a 3g as well. i dont know what rim it is but its carbed and auto. so im guessing Lx. anyway...his speedo shakes a lot. like if he's going around 30 mph...the spedo reads something between 20-50 just shaking up and down.


so what would he have to do? replace the cable?

[Listen2myBASS]

my rpm gauge does that...maybe its the gauge itself...

[A18A]

my rpm gauge does that...maybe its the gauge itself...
could be your ignition, theres no way the speedo is associated with the tach... check your coil and dizzy


o yeah, i noticed my speedo is really jumpy at sometimes, when going about 50ks at a steady speed, the speedo bounces about a 5k difference

[Listen2myBASS]

i never said it was associated...im saying JUST my tach does that...it could be the same problem as there having with the speedo...i changed my dizzy so ill check my coil...but iunno...

[shepherd79]

replace speedo cable and problem will go away.

[Listen2myBASS]

what about me?

[ChaseR]

That is correct, On my old LX My speedometer bounced... Cable was replaced and the problem was gone...

[A18A]

what about me?
what about you?? nah j/k...... my tach was very very bouncy for a little a few minutes, it wasnt untill the dizzy fell off the cam that i realised what the problem was.. but chances are most likely the dizzy or coil/wires chances of it being the tach itself would probably be 1/94376534

[Listen2myBASS]

koo

[mkymonkey]

anybody have pics of the speedo cable? so i can show him, plus i dont know where it is or which one it is lol.

tia

[A18A]

anybody have pics of the speedo cable? so i can show him, plus i dont know where it is or which one it is lol.

tia
its in the tranny kinda behind the block, just need a 10mm socket and a screw driver or 2 :)

[mkymonkey]

ok...anyone have a pic?

[A18A]

i can go get 1 if u really want me too....

[mkymonkey]

ok go for it :D

[AC439]

This focus of this thread has changed from inaccurate speedo to bounty speedo. I think the bounty speedo issue was greatly discussed before and the soln is to replace the cable. I oiled the cable and it works (cheap way), at least for now.

For the inaccurate speedo, I figured out a way to recalibrate the meter. When I put too much oil to lube the cable, the excessive oil got into the speedometer and making the vehicle speed 2x the actual speed (I posted this months ago). So I took apart everything and cleaned the speedometer and found it is a magnetic coupling design with spring counter force. Therefore, the accuract of the meter is determined by the spring force and can't be changed. I found out that the needle can be completely removed. So, I took the needle out, and put it back in the way that it slightly rests below zero (you've got to determine how much you want the needle to rest below zero). Then put everything back and the indicate speed becomes a little closer to the actual speed although still off. You probably have to play with it a couple of times to get it close to the accurate speed. Sometimes, I use the automatic road side police radar speed indicator to compare to my speedo and usually I'm about 5mph faster on the speedo than the actual speed. An alternative is to get a pair of FRS radio and ride with a buddy who has an accurate speedo and compare speed side by side and readjust the needle on the speedo.

[Morthane]

For U.S. drivers, by far easiest way to compare your speed is to get a buddy with the current gen civic. Get both cars on the highway, and get your Accord in the left lane, just a few feet back from being nose to nose with the Civic so you are in the Civic's blind spot. From the driver's seat, you should be able to see the Civic's digital spedometer and compare!

Doing it this way, I found out my car was actually within 2 miles or less of the Civic's readings. Woot.


As for jumpy tach, I think this is a pretty standard issue with vehicles this old - my dad's '89 Camry flutters a little, and both our tachs 'stick' a little while accelerating. If you are just daily driving, it's not going to destroy your car by any means... just an annoyance.


If I had a scanner.. I'd do some favors. Alas, I do not!