OK here are the fact than i I'll ask my question:

My buddy that i bought the car from told me that for about 6 months the speedometer didn't work.
He admitted to me that a Mt. Dew exploded and got the speedometer wet(don't know how the hell he did that!)
From time to time the speedometer will jump from like 65 to 70 than back. (example)
Tires i have on it are 205/60/15
Stillen body kit
Lowered on Eibach Springs like 1.5" to 2" (not sure)
Car does not look like a champ at the moment. Kinda ghetto (work in progress)

Question:

I got pulled over tonight and my speedometer said 65 but the cop said he clocked me at 73 and paced me at 73 and just had his gun recalibrated today. Luckily he didn't give me a ticket. I was leaving a bar (but still sober) so i wonder if that was it. I asked him if there was a way i could have my speedometer check for accuracy. He responded with some crap about lowering a car can effect thing like the speedometer accuracy but i don't see how. Obviously it can reduce the drag from underneath but that would just give me more pedal RIGHT? My question is there any truth to the statement the cop gave me? Or could it be my cluster or speed sensor?

 

The cop is full of it on the lowering thing,probably the speed sensor,or cluster.

As you are driving, smack the top of the dash over the instument cluster,and see if the the needle moves,if it does then the instrument cluster is most likely the culprit..

 

A non-standard wheel/tire size combination, CAN distort the speedometer

 

Check the instrument cluster, speed sensor and wire and connector...And don't listen to stupid cops!

 

i have stock rims with 205/60/15. i know changing the diameter can threw off your speedometer. i followed a friend my speedometer said 55 his said 85 and he is riding on 13" wires on like 185/60/13

i figured the cop was full of ****! about a month ago i was driving down the freeway and my girlfriend was following me in my other car (04 Chrysler Sebring) her speedometer said 60 mine said 65

So does anybody know how to check the cluster of speed sensor?

 

your tires are not the factory size. therefore your speedo will be off. that sounds about how much mine was off when i was using that tire size

 

your tires are smaller than stock by 5% so your speedo will read faster than you're really going by roughly 1.9 mph.

the air pressure in the tire can change the readings slightly as well. too low and it will act like you have a smaller tire and too high it will act like you have a larger tire.

 

right so than that should support like when i said my girlfriend said she was doing 60 when mine said 65. OK so that's what i thought the cop just thought he hit pay dirt when he pulled me over. unfortunately i have insurance and i was not drunk. No disrespect to anyone that is a law abiding officer but i hate F@@CKING COPS!!! In my city i have been pulled over several time and each time i show them my insurance they act like they saw a ghost. Yeah i know my car looks ghetto right now with the primer spots but it runs like a champ and it's paid for. cops in my area will pull over a crappy car doing the speed limit way before a new car speeding swerving. trust me i know from experience!

 

I would agree with this too. I had an 89 Ranger with Hydraulics and 13x7 wire wheels. So by going down 2 wheel sizes it threw the speedometer way off. Lowering had no effect, just the tires.

As for the speedometer problem of not working, mine does that occassionally. I'm going to buy a new cluster off of ebay (only $30 shipped vs. $90+ from Auto Zone) and if that doesn't cure my problem I'll probe around at the other parts everyone advised.

 

according to the tire calculator (located in the stickies in the tire and wheel section BTW) your tires are 3.2 percent too fast. If your tires are not 100 percent, they are probably even farther away from that.

So, if you are going 60, your speedo will say 58. Your speedo gauge is probably screwed up, too.

 

My speedometer intermittently "goes out". When this happens, it reads 0 mph. It can then later come back to life reading the correct speed at it's own will. I am reasonably sure that it's not the actual speed sensor, because I have used my cruise control while the funny speedometer action happens, and the cruise control seems to have no problems regulating the speed. So, the problem is with the speedometer being funny, apparently not the cruise control or whatever that uses to sense the speed. Is there a common place in the instrument cluster that goes bad and can cause this? Could it just be a bad ground in there somewhere? Ive never had my instrument cluster apart so have no idea what I'm in for. Also I have not experienced any other funny activity in the cluster (except for the temp gauge going out... always thought that was a loose temp sender terminal, but just now it dawned on me I wonder if they are related. Temp gauge going out is not correlated with speedometer going out though.) Any tips would be appreciated. Thanks.

 

check your speed sensor....it most likely isnt the cluster...happened im my max and my friends parents max...cluster wouldnt intermittently work

 

if anyone wants a cluster, PM me i have one for sale if you think it is the problem

 

actualy from what i found they are -0.80 % smaller than stock so when my speedometer says 65 mph i am doing like 62.96 mph

 

too fast and smaller are the same thing...too fast because they are smaller causing the tire to spin more. get a new cluster and be happy you didnt get a ticket.

 

already on the look for a cluster with the white face gauges. any one got one at a good price?

 

I've got a VE one with 137k on it
PM me with an offer

 

If you buy one form Brian or anyone else you can change the mileage to match what you have on your car now...its not hard to do.

 

yeah i'm not too worried about the milage as long as it works. But unless you can beat $20 i already found one on NWMAXIMA.COM

 

Really?...I have a SE gauge cluster I had decided not to insall because I thought the mileage wouldn't be accurate. I guess I really haven't looked into it...Care to share how?

 

I cant do a write up or anything because its been a long time since I did it but if you study it you can see what you need to do. Just undo the motor and maybe take out the gear (like I said its been a while since I did it) so you can move the numbers where you want. Then just put it all back together.

I did it when I replaced the GXE cluster I had with an SE cluster. I have also just taken the thing out and swapped it once on my SE when I replaced the cluster on it.

 

Here's a good tire calculator to check approximate speedometer error with different tire sizes. Keep in mind that a certain size can vary for each tire model in that size.

 

Thanks for the info...it's been awhile since I saw a newbie with >15 posts contribute. Good work!

 

I can do a writeup for anything related to replacing stuff in the cluster. I've got a load of 1600x1200 pictures and some smaller (i forgot to set my camera corretly) pictures too. I replaced a speedometer that did exactly what yours does, and I also replaced my odometer motor, which was seizing up in about 4 points during its rotation. Unfortunately, I can't post new threads yet, so I may have to post the writeup on here. If you don't spend too much time looking at stuff, you can have it all out, fixed, and on the road in under 2 hours. I didn't like the presence of some random sticky substance on the connection side of my cluster, so I swapped cluster casings, so I've actually removed and replaced every single part on the cluster, with the exception of the trace-sheet and underlying resistors or diodes or whatever's under it.

As for the temp gauge, I did an almost-WOT 0-70 merging onto the beltline, and my temp gauge dropped to the C line (not under it, but on it) every time I hit the 5000+RPM area. As soon as it shifted into 2nd, the temp gauge read correctly again, and dropped as I hit 5000rpm in 2nd. It also sometimes flutters around, but only about once a month.