Christobal65

After some searching i've seen a few other people with a similar speedo error but no one seemed to ever post a fix for the problem. Is the VSS the same for all 4th gen's? Did they change the number of teeth on the gear for better accuracy?

On a recent road trip in the Maxima I brought the GPS along and while cruising at an indicated 80mph the GPS said i was really doing 75-76mph.

pmohr

iTrader: (26)

All sorts of old people popping up recently, weird.

What size tires do you have on the car?

There were two speed sensors, a 30 tooth and a 33 tooth (according to FAST). Looks like '95-'99 4AT are all the same, '95 4AT/5MT are the same, and '96-'99 5MT are the same. Never seen a difference, though.

Christobal65

Its a 1996 SE 5spd just for reference.

Stock wheels and tires, and not really looking to go to a taller tire since there is already a ton of sidewall on the stock 15's.

pmohr

iTrader: (26)

So you're still running 215/60/15s?

I don't see anything about calibrating the speedo, but it's never going to be spot on. If it's only off by that much at that speed, honestly I wouldn't worry about it.

Christobal65

I dunno since every other car we had the GPS in was basically spot on including the 92 explorer i drive daily that was off 1mph at 75mph....

I dunno i find it really annoying to know that the maxima actually has nearly 10,000 miles less on it then the ODO shows

TunerMaxima3000

iTrader: (4)

How old are the tires? (how much tread)

Christobal65

4/32 or so, still it shouldnt be off by nearly 6%

aznsap

iTrader: (29)

if your speedo is reading low, there would actually be 10,000 miles MORE on the engine/car than the odo says.

regardless, i have the same problem. my speedo i noticed is off like 5-10%. it reads low, my gps tells me im doing over 80 when my speedo says 75.

i thought it was because i did my 5spd conversion, but i guess other people have this issue too. im running stock sized 205/65/15 right now, but i noticed my speedo is off even more when i switch to the 2003 17" SE wheels.

also i have a '95 with a '01 5spd in it.

Christobal65

Uhh my Maxima reads HIGH like i said in the first post.

Well I'm not sure why yours is the reverse of mine, but my Maxima is 100% stock. No mods no swaps, no nothing other then general maintenance. And this car has always been this way, since new.

95max327

iTrader: (-1)

they usually are off by 6% once you get over 85mph, i dont know why yours is doing it at 75 ish but whats gps reading at like 40 or 50mph? over? under? perfect? my old 96gxe use to tell me im doing 140 when i was doing 125ish.. and my ford thunderbird SC 5speed told me i was doing like 40 at 25mph but then when i was going 115 my speedo was burried and it ends at 120.. so i dont know why it does it but your tires make all the diffrence

TunerMaxima3000

iTrader: (4)

No offense, but if you only have 4/32" left, your speedo will be out around 3%, factor in a 1-2% variance at high speeds on the stock equipment, and the fact that GPS devices, while fairly accurate, are not 100% accurate, and you have your complaint explained.

When I put on my 350Z 18's my speedo turned unexpectedly perfect according to my friends blackberry GPS, yet when I put brand new stock tires and rims on it was off about 4mph.

If you had stock size rims and new skins, and it was off that much, I'd see you having a valid issue, but otherwise, just take it as it is.


GPS is not nearly as accurate as everyone likes to think it is. Especially the lower end GPS devices (cell phones, etc.)

Maxgig

iTrader: (5)

+1 on the gps not always being accurate. I have 17in 350Z rims on my 03 Max and my gps always shows me going slower than my speedo indicates. I've just learned to accept it.

Christobal65

LOL GPS not as accurate as a speedo? are you guys serious? Do you not understand how GPS works? (I'm not talking about a cell phone either here since many of them use cell towers to help determine your position.) The GPS system is based 100% off of time. To be more accurate its difference in time measured in nanoseconds (one billionth of a second).

Garmin says that the avg user should expect accuracy with in 16-33ft. So if there is 5280ft in a mile and you do (33/5280)*100 you get 0.625% error in a mile. Even if you go worst case scenario at 49ft error you are still talking about less then one percent error (0.93%).

As for the tire wear claim its not quite as valid as it may seem since passenger car tires normally have treads 11/32 of an inch deep. Now wear bars show up at 2/32" which means there's only 9/32" tread wear to work with. My front tires are around 4/32 (possibly more but i'll just use that number since thats what i stated) so that means 7/32" has worn off. Now that means 14/32 of tire is now gone...less than half an inch. now my tires have a circumference of 77.75" vs 79.12 which means 1.7% error. Meaning there is still 4+% error that is there even when tires are new.

Now i freely admit that tire wear is part of my issue, however i just found it odd that a car had 4% error with NEW tires. Normally the given 'error' range of a speedo is there to account for tire wear, so that at any time in the tires life you could take it to a dealer and say "my speedo is off" and the dealer can say "its within given rage of error." So now at this point in time and until i replace my tires my maxima is now OUT of spec.

(sorry i didnt mean to rant but i found it highly amusing that some of you were seeming to say the error was in my GPS and not the car)

TunerMaxima3000

iTrader: (4)

haha I am glad you had the time to do all the math.

I WAS referring to cheap GPS as I stated, all I said was they're not 100% accurate.

No one said GPS is less accurate than a speedo.

If it's that much of a bother take it to the dealer.

You can try replacing the VSS, as I'm fairly sure there is no adjustment on out cars as far as calibration goes.

Christobal65

yeah i was bored last night

yeah well that pretty much answers my question I was kinda hoping there was an updated VSS with a different number of teeth, but since theres not we'll just have to deal with it.

nalc

iTrader: (11)

My speedo reads a little higher than it should too (usually seems to be about ~4 mph faster than the car actually is around highway speeds)

I don't mind it... it keeps my speed in check so that I don't really get pulled over *knock on wood*

Gman8990

iTrader: (6)

Mine has done this ever since i put on my new tires that were a little smaller but wider than stock... Im off about 2-3 mph...

max ride 41

iTrader: (4)

ok, i had my speedo idle checked by computer and the engine is idling correctly but the speedo is showing it lower??? i swapped the original gauge cluster awhile back cause the odo stopped working, then i added indiglo gauges that sit on top. the temp one sticks, but i never noticed the speedo till i changed idle control valve??? weird, must be cause of better air flow and maybe a faulty speedo sensor??

TunerMaxima3000

iTrader: (4)

What do YOU think the reason could be?

max ride 41

iTrader: (4)

dont know, the car does have 186,000 miles on it. could be either or both.

TunerMaxima3000

iTrader: (4)

Are you messing up your terminoligies maybe?

Speedometer - reads the speed you're going and correspondingly runs your Odometer

Tachometer - reads your engine RPM (idle)

What the hell are you trying to say in this post, cause to me it makes no sense at all.

The ICV's only relation to your speedo is some wiring, they do not affect one another.

Xfactor22

iTrader: (13)

im having the same speedo read out problem, my girlfriend was driving next to me and we agreed to keep up at the same pace of 80 miles an hour, and she started to pull away from me. we eventually were going the same speed, but my read out was 5-7 lower than hers... i dont get it

ImmaSquashYou

iTrader: (7)

just think about all the time the max saved you from a ticket..-= )...you thought u were going 80..but really 75 in a 65....

i know they have speedo healers for bikes..not sure about the cars tho..

95max327

iTrader: (-1)

mines off by 3mph

bksmax11203

iTrader: (1)

Hey, would u check ur speedo to see if it's not??? I just picked up my 95 max se from ny last night, and let me say first off i loves this ****in car lol, but i noticed that i had the cruise control set to what looked like exactly 70 while going through nj and for some reason there was a numerous amount of cars flying past me.... So i'm wondering if i was really going 70 because in my old car toyota cressida with a manual conversion or in the stock automatic, at 70 i used to be passing them. Also for references, On the cress i was running supra 5 spoke rims (16's) and on the max 350z rims (18's)

ImmaSquashYou

iTrader: (7)

thats because if you're on the turnpike.....70 is considered slow...LOL.....most people are doing at LEAST 75....and 80 on avg...

BuRoJo

The speedo is calibrated to the circumference (distance traveled per one revolution of the tire) of the tire the car came with from the factory. The easiest way to keep the speedo accurate is to buy tires with the same circumference as the original. TireRack provides tire dimension data online under the "specs" tab when you are looking at the page for any individual model tire.

My 97 GXE came with 205-65-15 and I went "plus zero" with 225-60-15, based on the data provided by TireRack. I used the "revs per mile" data for comparison. (815 revs per mile for the 205's vs. 811 revs per mile for the 225's) Have not calculated the difference but my speedo readout always matches those RADAR speed limit signs I run by every now and then. I have gone by these signs from anywhere between 25 and 75 mph and my speedo has always matched the RADAR sign's display.

If I am not mistaken, the speedo setup for the Max is mechanical, so the calibration is based on the gear size where the speedo cable engages the trans and is not something that is going to drift. (please let me know if this is not the case)

pmohr

iTrader: (26)

The Maxima hasn't had a speedo cable since what, the 2nd gen? Even they may not have.

BuRoJo

LOL Shows what I know!

I guess the point I was trying to make is that I have had pretty good success in maintaining speedo accuracy by keeping my tires' circumference as close to stock as possible.

99BlackMaxMS

iTrader: (85)

Wow this thread is all over the place. My speedo is off by 3 or so mph by 80mph according to my Garmin. I have brand new tires for the winter on my stock wheels, so that shouldn't be changing anything.

redwagon29

iTrader: (2)

I have read that manufacturer's do that to save their butts. It is better for them to be overrating your speed than it being less, because if your speedo stated you had cruise control at 75 and a cop pulled you over for going 78 you would be BS, where as if you had cruise at 78 and a cop clocked you at 75 you wouldn't be. They aren't required to be spot on. If you ever see a cop car or a Police Interceptor version of the crown vic you will see on the speedo it says "Calibrated" meaning it should be spot on (minus tire wear). I have a Magellan GPS and with brand new stock 215/55-16 tires on my 97 SE I will read 76-77 on the GPS when the speedo says 80, which is about a 4 % difference.

Christobal65

except there is still a mechanical piece to it, the VSS just takes that mechanical signal and sends it to the gauge cluster as an electrical signal.

pmohr

iTrader: (26)

Indeed, it's just two plastic gears, that's where it ends.

What about it?

Christobal65

that was my point. The sensor is indeed mechanical, gear driven, and the signal is electrical. I was just clarifying that you were both right

BuRoJo

Thanks for pointing out that the VSS is actually a mechanical/electronic interface between the transaxle and speedometer. (although I should have done a little homework before commenting; I try to be helpful rather than critical when I post)

I did a quick check in my FSM on the VSS and the speedometer. Only found diagnostic/troubleshooting info, nothing about calibration.

Perhaps someone knows whether any of the following is relevant: Is there some sort of vernier adjustment on the gage cluster? Perhaps one would have to hack into the ECU to get to the calibration settings? Would mechanical wear of the gear in the VSS cause the variance but escape triggering a fault code in the ECU? etc...

Dbird

probably the tires.