Smart Car of America Forum banner

1 - 20 of 20 Posts

·
Registered
Joined
·
3,266 Posts
Discussion Starter #1
Oh you guys are gonna love this:

- I was going 75MPH for 15 minutes just now, it felt a bit windy so I took my eyes and hands off the road (oh relax; my knee can hold the wheel) while i checked the scangauge. I was traveling at 90MPH the whole time.:think:

-is the speedometer broken since the 2.0 update 2 weeks ago? -My TPMS keeps alerting me every 5 minutes, but my tires are at 40psi. Maybe it's my whole computer ready to die?
 

·
Registered
Joined
·
1,709 Posts
The Scangauge gets its info from the computer. The speedometer, I'm not sure if it's the same source or if it's tied straight to the wheels like in the olden days. To get a 99% accurate speed measurement, get on a highway at what you think is 60mph, then count how many seconds it takes to go between mile markers. 60mph = 1 minute, 90 mph = 40 seconds. 75mph = 48 seconds

Or try GPS. If you have an iphone, download the InstaMapper GPS Tracker application which is pretty accurate.

If you were just at the dealer, and they did ECU work just prior to some weirdness, definitely call them about it.
 

·
Premium Member
Joined
·
11,309 Posts
The speedo gets the info from the same place. Find a local police car using a radar gun and ask them. They are usually pretty helpful. Or get a buddy to pace you in another vehicle, that should give you a good indication well within 15MPH.

Best thing is to get in touch with the dealer. They do have a service network that can at least identify if the problem has happened before.
 

·
Registered
2017 Passion Coupe
Joined
·
3,552 Posts
smartacus - have you altered your instrument cluster in any way such as putting in custom graphics for the speed indication?

I'm sure they've covered in the other thread that the TPMS is relative, needs to be reset to a "baseline" and will give a TPMS error if one of the sensors has failed. But the speedometer being off suggests to me there's a mechanical problem with the stepper motor and needle assembly. Either that or your tires are significantly different in diameter from stock.

My 2.0 upgrade and multiple accesses to the innards of the instrument cluster still leave me with the ~2mph high reading that I've had all along (and saw in my previous car as well).
 

·
Registered
Joined
·
371 Posts
I have done nothing to the drivetrain. But my spedo reads low compared to the GPS. At 50MPH on the speedo, the GPS says 48.
 

·
Registered
Joined
·
755 Posts
I have done nothing to the drivetrain. But my spedo reads low compared to the GPS. At 50MPH on the speedo, the GPS says 48.
That's about right, the speedometer usually is about 2-3 mph "faster" then the actual speed. I wont get into details why they do this but it's setup that way.

On my scangauge it shows the actual speed of the road while the speedometer shows a few miles per hour over.

Larry
 

·
Registered
Joined
·
3,266 Posts
Discussion Starter #8
smartacus - have you altered your instrument cluster in any way such as putting in custom graphics for the speed indication?

I'm sure they've covered in the other thread that the TPMS is relative, needs to be reset to a "baseline" and will give a TPMS error if one of the sensors has failed. But the speedometer being off suggests to me there's a mechanical problem with the stepper motor and needle assembly. Either that or your tires are significantly different in diameter from stock.

My 2.0 upgrade and multiple accesses to the innards of the instrument cluster still leave me with the ~2mph high reading that I've had all along (and saw in my previous car as well).
No mods of any kind. stock everything. completely bone stock.
 

·
Registered
Joined
·
1,883 Posts
I noticed that "Maggie" my Magellan 1475T reads less than my speedo by about 2-3 mph. I wonder if the odometer is off by a similar amount since the old cable type speedo/odo units got their input from the same place.
 

·
Premium Member
Joined
·
11,309 Posts
The speedometer measures SPEED, the odometer measures miles traveled. You will travel the same number of miles just at a slower speed,, or longer time. Miles stay the same...

I checked the miles by using the old highway mile marker test over a 10 mile stretch of road and I did not see a discrepency. Looked OK to me.
 

·
Registered
Joined
·
3,266 Posts
Discussion Starter #13
Guess wha

Took it to smart center orlando, reprogrammed the computer , tech said it's just fine now. Drove home and uh... it's still governed at 75MPH. and uh...it's still showing 90MPH on GPS. I might not be taking my car back there again.
 

·
Registered
Joined
·
1,709 Posts
Sounds like the computer may be fine but the speedometer needle may be limited. Have the SC Orlando tech go for an actual test drive. You need to know if you're going 75, 80 or 90. If the speedometer shows 75 and you're really doing 90, Smart USA doesn't want you suing them. They'll accommodate your request for accuracy one way or another.
 

·
Lifetime Member
Joined
·
11,307 Posts
I was going to ask exactly what JohnH said. I did a background change and it screwed up the pod just like you are describing. I have since switched the car back to stock and drove the car 400 miles yesterday and the speedo was around 3-5mph fast from SGII and GPS (SGII and GPS read the same).

Service tech needs to DRIVE the car, see what is happening and then most likely order a new speedo assembly once they agree with you.
 

·
Registered
Joined
·
3,266 Posts
Discussion Starter #16
I was going to ask exactly what JohnH said. I did a background change and it screwed up the pod just like you are describing. I have since switched the car back to stock and drove the car 400 miles yesterday and the speedo was around 3-5mph fast from SGII and GPS (SGII and GPS read the same).

Service tech needs to DRIVE the car, see what is happening and then most likely order a new speedo assembly once they agree with you.
At 60MPH problem starts (it should be showing closer to 65). By 75MPH, the actual speed on GPS AAAAND SCANGAUGE is 90MPH.

Car is assembly stock bumper to bumper. I don't even know of any background change. Gimme the website.
 

·
Lifetime Member
Joined
·
11,307 Posts
Mine had originally done exactly as yours but as I said, it was because I opened up that speedo. What was weird is it would be intermittent. Once returned to normal stock configuration it stopped.

My problem would start as low as 20mph. During my 45 mile commute it would normally correct itself before I made it to work (not always). I would give Orlando a second chance but make the tech drive the car and actually see what is happening....and of course make the tech drive car once he has fixed it too.
 

·
Registered
2017 Passion Coupe
Joined
·
3,552 Posts
Bottom line: the system knows the speed (as witnessed by the scangauge) and the "analog" needle is much closer to digital. The needle "motor" is controlled by delivering the specific number of revolutions to deliver the desired deflection through the reduction gears.

If you're reading 75 at 90, I'm guessing (notice the use of the engineering term) that the motor has "slipped" for many of the revolutions. If this is the case, then backing down to 15mph should give you a reading of about 0mph. If, instead, you go from your governor-limited "75mph" to 20mph (as roughly agreed upon by your both scangauge and speedometer) without a discrepancy then there's something more insidious going on here.

The DIY Speedo background could put drag on the needle making the motor slip a revolution or hundred which is why I brought that up. If there's other issues (bug or component in the way) to produce the slip, the cluster would need to be repaired or replaced.
 

·
Registered
Joined
·
3,266 Posts
Discussion Starter #20
Conclusion: Went back to smartcenter; tech plugged in his computer, his computer kept calling me a liar even on I-4, got it up to almost 90 (sorry , heavy traffic precluded 90) before he finally agreed something might be amiss.

He reflashed my car and figured it might have had something to do with the 2.0 flash that I kept saying started it all.

I could have and should have gotten a reckless driving ticket, and points/ insurance et al because he wasn't gonna take my word for it until I scared him out of his bladder.

- Why did I have to prove myself ; NTM i'm supposed to be the customer. The customer is always right. Even Mary Poppins told her employer to his face : I never explain anything.

-Oh God I wish that other tech Garrett never left :(
 
1 - 20 of 20 Posts
Top