Auto Mechanic in the Forum?

Motzart

I just bought a 1995 2dr Ford Explorer Sport 4WD.
Has 104k 4.0 6cyl Auto with OD.
LOW milage for a 95....seen SEVERAL Exploders with 150k+ and even 200k!

Anyway.....
Driving it home speedo said I was doing 60mph but the Wife was following me and said I was doing 45mph
I'm thinking a Speed Sensor on the Transmission?
Dealership beats around the bush as to this being the problem
(ofcourse they want me to have them check it and charge me a wad)
All I got was.....
"That's a cheap place to start"
When at all possible I fix my own.....saves me HUGE dinero!

Anyone able to shed some light on this speedo problem?

MikeC78

Are the wheels and tires the original size?

Kex

I can't help you with diagnosing or repairing that specific issue, but if you want to check it for sure, you could use (or borrow) a GPS device to verify what your wife noticed, although given such a huge discrepancy, I can't imagine that she would be that far off. Speedometers are frequently off by one or two MPH, but fifteen is not normal! The question I would also be asking myself in this case is: does this also mean that the tachometer mileage is also wrong (showing a proportionately higher number than the actual mileage driven by the vehicle)? If true, that difference would then depend on how long the problem has been present.

Jstas

MikeC78 wrote: »

Are the wheels and tires the original size?

DING!


I see pickup trucks and SUV's with all kinds of speedo and anti-lock braking problems because of wheels and tires too tall or too small for the acceptable range. Especially with the advent of 20+ inch wheels and everybody wanting to look cool with the bling bling dubs.

Also, another things might be a different gear set from stock in the rear differential. Especially if it was repaired with a junkyard piece with "posi" or something equally desirable by those with only a passing knowledge of what's "cool" or why.


Another thing I just thought of is maybe the Exploder is fine and it's your wife's hot rod that is whack.

ben62670

If the tires are oversized the speedo will read a lower speed.

Ricardo

I doubt that tires size will give a 25% difference in speed reading.

Motzart

235-75-15 tires..exactly what the door tag says it takes.
That was the 1st thing I checked!

raidersrule76

If the axle was replaced being that it is a 4wd that would mean that both would have to have been replaced or the 4wd wouldn't work properly there would be alot more problems than just the speedo.

Jstas

ben62670 wrote: »

If the tires are oversized the speedo will read a lower speed.

Hence the reason I said too tall or too small. Wasn't trying to diagnose the problem, just give ideas on what it could be.

Ricardo wrote: »

I doubt that tires size will give a 25% difference in speed reading.

I have tires that are .4 inches taller than stock and .2 inches outside of the acceptable range and I have a 5 MPH difference on my speedometer. I've seen people with a wheel/tire package that ends up being almost 2.5 inches taller than stock and end up with a 20+ MPH difference on the speedo. It doesn't take alot to make a huge difference.

Also, going from say a 3.23 final gear ratio to a 3.73 final gear ratio will produce a large difference in reading.

raidersrule76 wrote: »

If the axle was replaced being that it is a 4wd that would mean that both would have to have been replaced or the 4wd wouldn't work properly there would be alot more problems than just the speedo.

Only if the 4WD was engaged. If the Exploder has that few miles on it for it's age it is likely it has never been engaged except in the tests at the factory.

vlam

Such big differences in real speed versus reading is usually not caused by tire size changed and you confirmed that.

There could be an issue with the Speedometer Sensor. It's about a $30 parts. It could also be a problem if it's using a different gear ratio than stock.

If I have a chance this evening, I'll look it up for you.

BTW.. I am not a mechanic.. just likes to work on cars and SUV in this case.

AudioGenics

just a suggestion to check the speedometer sensor and/or the speedometer cable.

(gosh I hope I don't get pounded for this....)

Motzart

vlam wrote: »

Such big differences in real speed versus reading is usually not caused by tire size changed and you confirmed that.

There could be an issue with the Speedometer Sensor. It's about a $30 parts. It could also be a problem if it's using a different gear ratio than stock.

If I have a chance this evening, I'll look it up for you.

BTW.. I am not a mechanic.. just likes to work on cars and SUV in this case.

I appreciate that Vlam!
Stange problem.....with all the electronic sensors and the like on these newer vehicles nothing suprises me any more.

To you youngsters a 1995 might seem old but to us older farts 1995 was just yesterday! LOL

Motzart

I appreciate the help guys!
I can't afford a auto loan and like to have something that's paid for.

1995.....102k......4WD....bullet proof engine good for 200k.
Has power winders.....cruise......AC all work....even a working factory CD player!
Needs rocker panels as they are rotted off and the bottom 2in of the tailgate is gone....both easy to replace.....$650.00 wasn't bad!
Usually Exploders same condition 1-2+ years newer and at least 150k miles are bringing $1800+ in my area.
This one with a lil fix'in around a $900 total investment I could easily get $1500 out of it!

AudioGenics

http://www.explorerforum.com/forums
The 95 does not have a cable.... MY BAD !!!

disneyjoe7

Was the Transmission replace? I did that myself many moons ago, the speedo gear in the transmission was wrong for that vehicle. If so it will error the speedo.

PhantomOG

I don't know squat about cars, but I wonder if the speedo problem has any correlation to the low reported mileage?

Does that even make sense?

Jstas

disneyjoe7 wrote: »

Was the Transmission replace? I did that myself many moons ago, the speedo gear in the transmission was wrong for that vehicle. If so it will error the speedo.

Good point

Motzart

joseph.v.chen wrote: »

http://www.explorerforum.com/forums
The 95 does not have a cable.... MY BAD !!!

THANX I signed up there....I'll see how it goes.

Motzart

disneyjoe7 wrote: »

Was the Transmission replace? I did that myself many moons ago, the speedo gear in the transmission was wrong for that vehicle. If so it will error the speedo.

I dunno but I doubt it.
From what I gather I THINK I'm only the 3rd owner.
PPL I bought it from only had it since Oct 08.

Dunno my 1992 I just had to junk only had 91k on it.
Body was pretty rusty but it came from Conn where they used a ton of salt.

AudioGenics

check the speedo gear that disneyjoe7 and Jstas both pointed out

I think they are right.....

ben62670

My 68 Bronco reads 45mph with 35" tires, and 3.50 gears at 65mph just to give an idea.

AudioGenics

WHAT IF.... the previous owner had larger tires but wanted to keep them.
The wheels and tires would be more expensive.... in Maryland you need stock size tire to pass inspection.... did not change the speedo gear and sold the Explorer as is.... (again as disneyjoe7 and Jstas pointed out)

Motzart

Hey with a used vehicle anything is possible! :rolleyes:

comfortablycurt

MikeC78 wrote: »

Are the wheels and tires the original size?

That would be my bet.

As others have said, it could be due to a replacement rear end, speedo sensor or any number of things.

Jeb85

Motzart wrote: »

I just bought a 1995 2dr Ford Explorer Sport 4WD.
Has 104k 4.0 6cyl Auto with OD.
LOW milage for a 95....seen SEVERAL Exploders with 150k+ and even 200k!

Anyway.....
Driving it home speedo said I was doing 60mph but the Wife was following me and said I was doing 45mph
I'm thinking a Speed Sensor on the Transmission?
Dealership beats around the bush as to this being the problem
(ofcourse they want me to have them check it and charge me a wad)
All I got was.....
"That's a cheap place to start"
When at all possible I fix my own.....saves me HUGE dinero!

Anyone able to shed some light on this speedo problem?

im not a ford mechanic, but i am a mechanic. If the tires are the same as what the door tag says then its gotta be speed sensor. Is there any damage anywhere by the wheels? if so check that wheel on the back of the backing plate for a speed sensor(it'll be the only thing with a wire going to it), only if its ABS. If its not ABS then check at the rear diff there should be a wire going to top left(looking from the back) of the diff from the front see if there is any corrosion on the connector(you will need to take the connector off and the pins on the connector will look green, also check the wires by moving the connector up and down while holding the wire about 1/2" away from the connector, if its really loose you got a broken wire, if its really stiff then its work hardened pretty much just as bad. and im sure you know what a good wire feels like so i don't need to explain that). If the sensor is at the tranny that may be a little trickier to find, but check for the same. it'll be a twisted pair wire(just 2 wires) going to the sensor and it'll be up at the front most likely.
hope that helps. If you want to check the sensor you'll need a dvom. if you want more info for checking the sensor just let me know.
hope this helps

gdb

Have you engaged the 4wd yet,(don't do it on dry road ) did it seem to drive OK ? If either front or rear axles were replaced with one of a different ratio that would be bad to say the least. That can be checked visually by jacking up one side and rotating the wheels and counting revolutions of the driveshafts (frt.&rear) I suspect either the tranny was changed or, as was mentioned before, previous owner put the wrong speedo drive gear in. If the gear from using tall tires was still in there.....you'd show that you're goin 85mph NOT 45mph:eek: Does the ABS system work when you do a "panic" stop? If they don't, I'd suggest that you bite the bullet and take it to a reliable repair shop. Chilton's and other model specific repair manuals can eliminate a LOT of guess work. Good luck and happy motoring !!:)

danger boy

my 2008 Ford Explorer company vehicle's speed is 2 mph slow according to the GPS. if the GPS is accurate. maybe the GPS is just fast???

disneyjoe7

I started to think that the rear end could be replaced also, having the wrong gear in it the speedo would be wrong. But you have a 4wd so I thought no.... But now I say maybe, can you put in 4wd ok and drive it? Start really slow if this is the problem.

wz2p7j

First of all, is the service engine soon light on? If not - disregard all posts above except the one about the wife's hot rod. There's all kinds of sensors on you vehicle. Transmission input and output sensors, vehicle speed sensor (usually the same thing as the output sensor), the powertrain control module knows the engine RPM and more. The powertrain control module knows if things are out of sync and will trip the light. Chris

Jstas

wz2p7j wrote: »

First of all, is the service engine soon light on? If not - disregard all posts above except the one about the wife's hot rod. There's all kinds of sensors on you vehicle. Transmission input and output sensors, vehicle speed sensor (usually the same thing as the output sensor), the powertrain control module knows the engine RPM and more. The powertrain control module knows if things are out of sync and will trip the light. Chris

If the sensor is functioning but returning an incorrect reading, that will not show an error code. The operational voltage of teh speed sensor and any other sensor has to drop below or go above an allowable range to trigger a light. It is very possible that the sensor could be faulty but not returning a code.

However, if the vehicle does not have ABS braking, it is unlikely that faulty speed sensor would return a code in a 1995 vintage vehicle. OBD2 was not mandated on cars until 1997-98 model years. A 1995 Explorer is very likely OBD1 and does not necessarily have the accommodations to monitor vehicle speed in that way.

AudioGenics

i found this on wiki...so no guarantees it is correct...

... 1996 and later Explorers that are EEC-V/OBD II ,
on some 1995 Explorers there is an EEC IV /OBD I test port under the hood, and a DATA LINK CONNECTOR (DLC) port for an EEC - V / OBD II system in the dash below the steering wheel.....