91-92 speedometer problems? info here

[NET]

Well last week one of my speedometer cables decided to snap on me. The only thread I found on this board regarding speedometer stuff that was relevant to problems was one that yikes started in the MK1 forum… so, I’m transferring useful info for the MK2s (I thought it was useful, anyway) while it’s still fresh on my mind.

First things first. If you’ve got stock rims/tires, this site has an RPM vs. MPH chart for the N/A as well as the Turbo that you can print out to stay out of trouble, or to keep from holding traffic up. The site has other info regarding speedometer problems, but ignore it til you read the rest of this. For the sake of being complete, here’s another site that has actual (not approximate/rounded) RPMs vs. MPH, but is much less user-friendly for purposes of looking at a piece of paper to determine whether or not you’re going the speed limit. This site would be useful if you wanted to take time to figure out the linear trend lines for each gear, if you need RPM vs MPH values that are >75 or <35 mph (or in a lower gear than what's been charted on the first site).

Ok, now that you’ve hopefully taken care of your paranoia issues, probably the first thing you should do if your speedometer stops working is check to see if your cruise control still works. If your CC still works, then the next thing you should do is check your cables. Get under your car and unscrew the (front) speedo cable where it enters the tranny. Spin the end of the cable to see if you get a reading in the dash. PatrickG did a little “how to” write-up for this in one of the threads over there:

Originally Posted by PatrickG

I just went through this same problem. It's a pretty straightforward and easy job once you get started. Here's a quick description of what I did.

1 - Jack up the car and support it with jack stands.
2 - Remove the rear portion of the under body panels (10mm)
3 - Locate the speedometer cable near the coolant hard pipes. You should see a rubber boot that covers the coupling between the front and rear sections of the speedometer cable. Slide the boot back and unscrew the coupling. I used a pair of channel locks and a 10 or 12mm wrench.
4 - Once you get the two sections separated, use a drill in reverse to spin the font section of the cable. Be careful not to spin the cable too fast... it may break. Have a helper watch the gauge cluster. If the speedometer responds, the problem is in the rear section of the cable.

Checking the rear section of the cable is a little harder because of where it attaches to the tranny. I found lying under the exhaust with my head towards the passenger’s side gave me the best access to the tranny connector. There may be an easier way, but I just worked around the obstructions. It would definitely help to remove the rear motor mount. Once you get the cable disconnected at the tranny spin it with a drill if there is anything left to spin. Mine was broken at this point and the keyed shaft was still in the tranny and not attached to the cable anymore.

If yours ends up being the rear section of the cable you will need to remove the drivers side engine lid side panel and the air cleaner box if you still have it. Once you remove these, you will have access to the speedometer cable and its mounts.

If it is the rear section of the cable it will cost you around $60 for the cable at the Toyota parts counter. Part # 83710-17150 - CABLE ASSY, SPEED. If it’s the front section it will be closer to $120.

Side notes for PatrickG’s write-up: You don't need a drill to spin the cable. Just spin the end of the cable counterclockwise between your thumb & finger, have someone else keep an eye on the speedometer. It should pop up to 10-15mph briefly if the (front) cable is good. Also, if your car is an automatic, your part # will be different than the one he listed.

If your speedometer AND cruise control don’t work, then it’s not the cables.

Originally Posted by rony

Does your cruise control work? Mine went out along with speedo, ended up being the gear sheared at the tranny. The job was actually kind of fun. E-mail me if you want more info on it. *email address removed—search other board if you want it* I managed to remove it without completely removing the (stock) exhaust, and without a c-wrench as most people thought you needed

Here's a useful link that everyone likes to share with others who are having speedometer problems (it's VERY helpful if you’re having speedometer problems that aren’t cable-related). Let me emphasize that it’s a good idea to check to see if your cruise control works first, and speedometer cables second, BEFORE tearing into your sub-assembly as shown on this page. Whenever I was searching on the other board, I’d find threads that people had started that said, “My speedometer stopped working earlier, what could be causing this?” and someone else would respond saying, “Here’s a useful site,” with this link. I didn’t have to go into the sub-assembly at all, and chances are that you might not have to, either. Save yourself time. Do the other stuff first!

If the problem lies within one of your speedo cables, partznet will beat your dealer’s prices. Partznet.com – speedometer cables (#1=front, #2=rear)

If the problem lies within the sub-assembly somewhere, the part numbers are listed on Stephen M’s website (same as above).

Thanks to those who contributed info to this, knowingly or unknowingly

[lmoua_07]

I did this on my but, my i fould that my pin broke, one that goes in the tran and the sensor. I homemade a pin for it but it worked fine to me. Save urself some money.

[MR-3sgte]

my cable is rusted away on the 2nd half going to the tranny. Toyota wants over 200 bucks for it OUTRAGEOUS!!!!

[Archidamus-R]

Yeah, the rear cable for mine was faulty. I could tell it needed replaced when I disconnected it and everything was rusted out of it . . .

[blackdemon]

life saver, I bought an MR2 with the speedo broken, along with the CC, I was gonna start with the cables, but this helped alot, thanks.

[ShackC]

Mine is down too, Now i know where to start thanks. Sure seems like a pretty popular problem with Mister Two. Wonder if it has something to do with the speed some of intend to drive, possibly breaking them??

[Nickels626]

I had the same speedo issue on mine and then i replaced it, than it worked for like two or three weeks than gave out and then i found out that it was for the wrong tranny i dont know how true that that was but i was wondering what it could be? also do any of you know were to get a cheap one or fix an old one?

[poptart3191]

yay!

[AndrewMr2]

Mine craped out too. At lest Im not racking up miles... LOL. No, but really I want it working. Im gonna do it over summer.

[blackdemon]

here's a new question based on this. While changing out my clutch I noticed that the speed sensor on the driver side wheel, is damaged, mainly one wire is severed from the assembly that goes in to the hub, and it's obviously sticking out. Haven't removed the gear assembly yet, but all the other parts appear to be fine. Can the cable be my problem?

[MISS_93'mr2]

You think this would be same for a 1993 n/a mr2? my Speedometer and Odometer stopped working *sigh..

[WrenchswingeR]

i know its an old post but Blackdemon, that wouldnt affect your speedo. The speed sensors on the hubs are the ABS brake sensors, speedo cables and/or speed sensors are in the transmission.
MISS_mr2 it doesnt apply to the 93+ mr2's because they use an electrical speed sensor instead of the very old school technology of speedo cables which read speed mechanically, not electrically.

[lmcleod4]

ok so i am way new here and new to the whole mr2s, but loving it (bought her 2 days ago). but i saw this post, and was actually feeling that the speedo was off a little, so i went and ran the numbers from that other site. well come to figure out that i was right. the speed o meter is 5 MPH fast. its not a big problem for me, (just minus 5 right? haha) but i was wondering if there might be something i could do to just tweek it back a little, instead of replacing everything since it is basically working with no problems. anyone know if anything? or am i just stuck doing the math until i feel like shelling out the $$$ for new parts?

[ShackC]

It depends on wheel/tire size. Gearing and other things, ive got to do mine too?