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Stock speedo problem

Jeepm@n

NAXJA Forum User
Location
Northern, WI
Not speedo's you wear either. Anyway my 94 is a bone stock 4.0l and AW4 with the 231. I've been noticing people passing me quite often lately. I had my speed checked by my local Sheriff (pays to live in a small town), and was told that my speed was 3.7 miles off at 60MPH. I checked the door sticker and the VIN with the factory options listing and I still have the right size tire. The GoodYear Wrangler GSA 225/75R15 on stock Jeep Ecco rims. The tires have about 7,000 miles on them. Can I calibrate this thing or am I stuck taking it to the dealer. I'm getting ready to put a 4.5 inch lift on it in July-August when I'm done setting up the 96. I'll swap the speedo gears then. I'd like this fixed so my girlfriend does not get a ticket for speeding because she thought she needed to add more MPH to the speed to run at the posted speed limit. Thanks
 
There's not really a way to calibrate it since it's gear driven.

But it is common for OEM speedometers to be off from the actual speed of the vehicle.

At least that's what I have heard.
 
just take that difference into consideration when you look at your speedometer. mine is off by about 10 mph, so i just do 80 when im supposed to do 70.
 
poorboy_616 said:
There is really no way to re-calibrate your, except for taking it to a $tealer....

BTW, 91 and up have Electronic speedos, not cable driven....

Huh? If you're going to give advice, you might want to actually know what you're talking about. Both the cable and the electronic sensor are both driven by the speedo gear.

JeepM answered his own question, really. The speedo gear can be easily swapped. The gears are $10-$15 from the dealer and sometimes dirt cheap on eBay. He's a good writeup from Go-Jeep that coers it pretty well and even has part numbers for you. http://www.go.jeep-xj.info/HowtoSpeedoGears.htm
 
Sorry to bring up an old thread... I'm just getting tired of reading through these...when they all say the same thing...

I'm just looking for clarification on the newer Cherokees. I just bought a '98. I am planning to put 30s or 31s on it.

My '94 Wrangler was just changing the speedo gear, but I was thinking the '98, having a more incorporated computer, might be something more then just a speedo gear.

So to fix the speedometer is it just the speedo gear still? or is there programming involved?

~Scott
 
Of course, resizing to a larger tire will take care of the underspeed indicated by the opriginal poster. When I put 30s on my '96 XJ I was actually nearly dead-on accurate for the first time.

Jst - yes, you still have a gear-driven speedometer; it's just electric through a Vehicle Speed Sensor (VSS) on the t-case. Changing the tooth count will change the indicated speed. Gojeep's writeup is one of the most comprehensive around.

Jim www.yuccaman.com
 
Anyone know if local law enforcement would help you check it without giving you a fine?(by speeding) I'm reluctant to take it to the stealership as thet want $145 to look at it and tell me how far exactly I'm off and what size gear it will need. Guess they are still pissed about the free catalytic converter on my 96 XJ. I'd say if I know how far off it is then I'd be able to find the formula for the correct gear on the speedometer.
Hasta Still beating the horse that won't die.
 
In your original post, you said you had it checked by a LEO and found that it was 3.7 off @60mph. Did he do it for free, or did he ticket you? My bet is it was a freebee.

There is a tool out there on the web to find the correct speedo gear based on tire size.
You could figure out what sized tire fits your error and put that one in.

But wait, you are lifting it 4.5". Are you going to do tires also? That will throw off your speedo, so perhaps you better wait. ;)

Most officers will not give you a ticket for less than 5 over at 60 as many factory speedos are less than accurate the faster you go.

You could do as I do: Remember that when it says 60, you are doing X and adjust your mind accordingly.

Ron
 
Jeepm@n said:
Anyone know if local law enforcement would help you check it without giving you a fine?(by speeding) I'm reluctant to take it to the stealership as thet want $145 to look at it and tell me how far exactly I'm off and what size gear it will need. Guess they are still pissed about the free catalytic converter on my 96 XJ. I'd say if I know how far off it is then I'd be able to find the formula for the correct gear on the speedometer.
Hasta Still beating the horse that won't die.


your speedo is fine if your only off by 3.7mph at 60mph. its only off by 5%. big deal!

i realy cant believe this is a problem?
 
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