Speedometer

[BerettaMN]

I havent found out for sure but I think my 90 beretta speedo is off. by 5-8mph. The speedo seems to me like its reading higher then Im moving. I drove the car for the 2nd time since I got it to work today and passed a automated speed limit sign that said I was going like 14mph speedo said 20. Anyone have any ideas?

[Barry]

Are you running stock size tires? If not, that can play with you speed rating based on a percent(offset varries with speed)

If its just off by a consistent amount, you can pull the cluster apart and move the needle. That is not easy to pull off perfectly though.

[BerettaMN]

everything on the car is stock except the cd player, old guy owned it, never been messed with

[Barry]

You could pull the vss and check for shavings

[BerettaMN]

Its probably on the trans huh? Id like to fix it without messing with the cluster needle

[Barry]

What trans? Auto or 5-speed?

[BerettaMN]

auto no overdrive

[SuzukiGhostRider]

Your VSS is on the tailshaft (end of it) on the trans. That would be passenger side behind the engine block.

You're CERTAIN your tires are stock size? It sounds to me like under sized tires causing a speedo malfunction, but a VSS irregularity is certainly possible as well.

Old folks won't "modify" cars generally but will usually just tell the tire shop "throw them on as long as they've got good tread" and tend not to verify size. We have to (almost everyday) explain to people what a different tire size will mean to their car and them if altered. Most people don't understand until we break it down why it's important.

Just a overwritten thought.

[BerettaMN]

Ill check again but its got the ugly 14's on it with the black center caps. haha

[3X00-Modified]

90 beretta is a hall effect sensor for the pickup from what I can see, and there is only a small worm gear shaft directly on the diff so there is no full length cable to deal with... I think its more of a display error than worn parts or improper tires.

And one thing that makes me think it's just the needle OR the speed sign you went by sucks... is the fact that you listed a 42% error on the speedo... You'd need a 315/85/14 tire to be that far off... and that would mean when your speedo is reading 50 you would be doing 35 actual... so yeah I think it's just the needle is off. They are never perfect.

If you have a GPS check it on that to see what it reads.

[BerettaMN]

Yeah I dunno maybe its just the needle like i said my 92 lumina and 04 impala were right on with it. I will see if i can borrow someone's gps and see what it says that way. Not a big deal to me, but the cops here it is. got a speeding ticket last year for 7mph over lol

[SuzukiGhostRider]

Well look on the bright side. Now you'll get one for impeding traffic, not speeding.

Yes, it is a hall effect sensor , and will have an electrical connector going to it. That was a typo on my part.

Your stock size on a 14" rim should be a 195/70/14.

It's a likely bad sensor or cluster. If the tire was undersized to even a 175/70/14 you'd only have a speedo variance of like 4%. At 20mph on your speedo you'd be doing like 19 mph. So not even close to enough.

[BerettaMN]

ha i tested it with gps driving next to a friend and some automated speed signs. its exactly 5mph off

[SuzukiGhostRider]

At all speeds? As in 60 means 55 and 20 means 15, etc? If so, someone has had the cluster apart and didn't install the needle correctly.

[3X00-Modified]

or its just not aligned and never will be... its hard to change the needle alignment on my cluster, you have two spots that work and one is 10mph fast and the other is like 2 fast... My Legacy is about 2-3mph fast all the time and same with Amy's Impreza...