Speedometer Problem

Duc_Rider · 06-10-2008, 08:03 PM

I have a 86 MR2 the speedometer is not reading correctly. It is under-reading the actualy speed of the car.

It is turning so I assume it is not the cable. What else could cause the speedo to under read?

Thanks

2restomod · 06-15-2008, 12:42 AM

Bigger tires?

Teado · 06-16-2008, 06:33 PM

First thing I would look at like mentioned above is the larger tires.

Also how far off is it?

Duc_Rider · 06-18-2008, 10:53 PM

No it has the stock tire size and stock rims.

The car did sit for a couple of years but it was in a garage. It worked when it was put away but now a couple of years later it doesn't work right.

It reads half the speed that the car is actually going. I lubricated the speedo cable incase that was the problem but it didn't change anything.

Cheers,

Ben · 06-19-2008, 12:07 AM

It might be the drive gear in the transmission that spins the cable, might have some broken teeth?

Duc_Rider · 06-19-2008, 06:23 AM

Can these drive teeth just breakoff just due to age?

Bak@EMSPowered · 06-19-2008, 01:38 PM

What year car & tranny? Do you have any sort of indiglo or aftermarket gauge overlays on your gauge cluster or is it still the OEM black faces?

Ben · 06-19-2008, 02:41 PM

Quote:

Originally Posted by Duc_Rider

Can these drive teeth just breakoff just due to age?

If it is like the MKII, the gear itself is made of plastic so its a possibility. Its a moving part so there is always a chance it will fail at some point.

If its like the MKII, it is really easy to check/replace. Just unscrew the cable and unscrew the adapter and it should come right out of the trans.

Duc_Rider · 06-20-2008, 12:24 AM

It is an 86 MkI no indigo back plate.

Thanks for the info I will check the plastic ring gear for the speedo. Man hope I can get another one from Toyota if it is in fact broken.

Drive safe,

SteveAW11 · 06-22-2008, 10:51 AM

Quote:

Originally Posted by Duc_Rider

It is an 86 MkI no indigo back plate.

Thanks for the info I will check the plastic ring gear for the speedo. Man hope I can get another one from Toyota if it is in fact broken.

Drive safe,

You can get that whole assembly that pops in your trans, and they are cheap as can be from the dealer, its actually 2 pieces. the gear and housing.

Id get both as your likely to damage the housing getting the old stuck one out.

Housing: 33404-12030
gear : 33403-19285

2restomod · 06-24-2008, 01:37 PM

Also, you might check just to see if the cable is connected properly at the tranny end. It has to fit into the slot gear of the tranny and sometimes they can be put in wrong without fully "locking" in place.

Duc_Rider · 07-15-2008, 08:19 PM

Got a new speedometer driven gear subassembly and replaced it even though the original looked fine. Still the same problem.

I then hooked up a drill to the cable to see if I chould get the speedo to move. It did not even move even a little. I pulled out the entire speedo cable and it was not broken.

I then took out the speedometer gauage and checked then noticed the the cable was not fulling going in to the back of the drive gear of the speedometer. It seems the outer rubber part of the speedocable streched and would not let the cable connect properly. I had to cut back the rubber and shorten it. Once I did that everything is now working and the cable fully connects to both drive gears. It beats having to buy a new cable.

I just thought even one like to know the actual problem and how I fixed it.

Cheers

Teado · 07-16-2008, 11:34 AM

Thanks for the update!

You fix, is just one more bit of info we can stash away.

My speedometer needle bounces a bit from 0mph ~ 35mph. but after that it holds steady, no idea why. Just another little bit of car character I guess.

CpuZapper · 07-24-2008, 01:16 PM

I had a similar bounce and lag in my speedo for quite a while. After a bit, it would make a lot of noise, occasionally jumping to the max. Finally the bushings inside gave out, the two magnetic bits made contact, and my speedo launched. The needle hit bottom, broke off, and just kept spinning. Made a neat looking gauge I guess. Replaced with another cluster and good to go.

06-10-2008, 08:03 PM	#1 (permalink)
Duc_Rider No Skills Join Date: Jun 2008 Posts: 6 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Speedometer Problem I have a 86 MR2 the speedometer is not reading correctly. It is under-reading the actualy speed of the car. It is turning so I assume it is not the cable. What else could cause the speedo to under read? Thanks

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06-15-2008, 12:42 AM	#2 (permalink)
2restomod msnusers.com/mr2projects Join Date: Apr 2007 Location: Queen Creek, AZ Posts: 377 Thanks: 23 Thanked 14 Times in 14 Posts My Google Map iTrader Rating: (3/100% )	Bigger tires?

06-16-2008, 06:33 PM	#3 (permalink)
Teado MK1 = My Daily Addiction Join Date: Jun 2008 Location: Oregon Posts: 272 Thanks: 11 Thanked 9 Times in 8 Posts iTrader Rating: (2/100% )	First thing I would look at like mentioned above is the larger tires. Also how far off is it?

06-18-2008, 10:53 PM	#4 (permalink)
Duc_Rider No Skills Join Date: Jun 2008 Posts: 6 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	No it has the stock tire size and stock rims. The car did sit for a couple of years but it was in a garage. It worked when it was put away but now a couple of years later it doesn't work right. It reads half the speed that the car is actually going. I lubricated the speedo cable incase that was the problem but it didn't change anything. Cheers,

06-19-2008, 12:07 AM	#5 (permalink)
Ben Same In The End Join Date: Aug 2006 Location: Oceanside, CA / Reno, NV Posts: 4,274 Thanks: 20 Thanked 309 Times in 284 Posts My Google Map iTrader Rating: (16/100% )	It might be the drive gear in the transmission that spins the cable, might have some broken teeth?

06-19-2008, 06:23 AM	#6 (permalink)
Duc_Rider No Skills Join Date: Jun 2008 Posts: 6 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Can these drive teeth just breakoff just due to age?

06-19-2008, 01:38 PM	#7 (permalink)
Bak@EMSPowered Banned Seller Join Date: Oct 2005 Location: Austin, TX Posts: 5,925 Thanks: 30 Thanked 193 Times in 165 Posts My Google Map iTrader Rating: (49/93% )	What year car & tranny? Do you have any sort of indiglo or aftermarket gauge overlays on your gauge cluster or is it still the OEM black faces?

06-20-2008, 12:24 AM	#9 (permalink)
Duc_Rider No Skills Join Date: Jun 2008 Posts: 6 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	It is an 86 MkI no indigo back plate. Thanks for the info I will check the plastic ring gear for the speedo. Man hope I can get another one from Toyota if it is in fact broken. Drive safe,

06-24-2008, 01:37 PM	#11 (permalink)
2restomod msnusers.com/mr2projects Join Date: Apr 2007 Location: Queen Creek, AZ Posts: 377 Thanks: 23 Thanked 14 Times in 14 Posts My Google Map iTrader Rating: (3/100% )	Also, you might check just to see if the cable is connected properly at the tranny end. It has to fit into the slot gear of the tranny and sometimes they can be put in wrong without fully "locking" in place.

07-15-2008, 08:19 PM	#12 (permalink)
Duc_Rider No Skills Join Date: Jun 2008 Posts: 6 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Got a new speedometer driven gear subassembly and replaced it even though the original looked fine. Still the same problem. I then hooked up a drill to the cable to see if I chould get the speedo to move. It did not even move even a little. I pulled out the entire speedo cable and it was not broken. I then took out the speedometer gauage and checked then noticed the the cable was not fulling going in to the back of the drive gear of the speedometer. It seems the outer rubber part of the speedocable streched and would not let the cable connect properly. I had to cut back the rubber and shorten it. Once I did that everything is now working and the cable fully connects to both drive gears. It beats having to buy a new cable. I just thought even one like to know the actual problem and how I fixed it. Cheers

07-16-2008, 11:34 AM	#13 (permalink)
Teado MK1 = My Daily Addiction Join Date: Jun 2008 Location: Oregon Posts: 272 Thanks: 11 Thanked 9 Times in 8 Posts iTrader Rating: (2/100% )	Thanks for the update! You fix, is just one more bit of info we can stash away. My speedometer needle bounces a bit from 0mph ~ 35mph. but after that it holds steady, no idea why. Just another little bit of car character I guess.

07-24-2008, 01:16 PM	#14 (permalink)
CpuZapper RallyRacer Join Date: Mar 2005 Location: Portland, OR Posts: 482 Thanks: 7 Thanked 25 Times in 22 Posts My Google Map iTrader Rating: (1/100% )	I had a similar bounce and lag in my speedo for quite a while. After a bit, it would make a lot of noise, occasionally jumping to the max. Finally the bushings inside gave out, the two magnetic bits made contact, and my speedo launched. The needle hit bottom, broke off, and just kept spinning. Made a neat looking gauge I guess. Replaced with another cluster and good to go.