91muddog

I have been suspecting my tach beinf off for some time, but never cared much about it.
When I rev to 3k as the tach reads, it sounds like my engine is going to explode! The highest it has ever gone is 3.5k

My spedo had been reading anywhere from 5 to 10mph off.
I got pulled over the other night, and not ticketed luckily, for doing 45 in a 35 when my spedo clearly read areound 38mph somewhere.

Again yesterday, I was following my dad in his 07 dodge pickup out at the camp grounds, my spedo didnt even register as his was a little above 5mph.

What are my options for fixing this?
Maybe some sort of after market guage cluster and pillar?

I deffinately want it fixed!
I am tired of being followed by the cops when there is noone else to keep speed with!



EDIT: I also forgot to mention, that when i turn my stereo up, the guages seem to twitch and flutter with the speakers.
They do this whit and without an aftermarket amplifier hooked up, and have done this with numerous head units all wired correctly to stock stereo wiring.

Zealot

Just a shot in the dark but ya might need a new speedo cable, other than that... maybe a short somewhere, I dunno ya got me.

stormin94

Could be a speed sensor, or a cable thats bad. maybe you need to tighten up something. Mine jumps around a little( like 5 MPH) but usually I can tell how fast its going. I dunno exactly whats wrong with yours. Good luck, hope this helps.

mehret

Nothing wrong with doing simple math while you're driving. Keeps you on your toes.

notanymore

when my gauges bounced to the beat it turned out to be bad grounds and make sure its not the gauges incorectly wired, instead of just the stereo. just a thought anyways. but i duno about the spedo

Jay351

Did your truck come stock with 28" tires?
If so going to a bigger tire will effect your speedo reading.
It will read slower then you are going.

Zealot

Well it says on his post that he has 30", that size wouldnt affect it that much. Different story if he had 32".

91muddog

it did have one stock tire and 3 31inch tires when i bought it.

traben27

I'm not so sure about that, going from 31s to 33s made a noticeable difference for me. Its off by 3 or 4 mph when i'm going 35. That is a pretty large gap though.

Well thats never a good thing. You really want to try to keep all 4 the same size, but I'm sure you knew that.

bigtrucknwheels

That Speedo would be 5.8 percent off. Its only registering 94.2% of the miles your driving. remember that when you are checking your gas mileage too. Divide the total on the trip meter by 94.2. that gives you the actual mileage. then divide that by the gallons it took to fill it for an accurate MPG reading.

so, at what your odometer reads as 38, is actually about 40. If its off more than that, then you got problems, or bigger tires than 30's.

My guess would be to check all the grounds. The metal in the cab seems to get a ton of surface rust. Unless your truck squeals at random behind the dash, i highly doubt its the speedo cable. Get it lubed anyways. Its not worth it to let the thing snap. Thats an expensive repair.

mehret

You mean divide by .942.


If it has 31s on it, you're going to be off by 5-10 mph. On my truck, my speedo usually reads 6 or 7 mph less than my actual speed.

bigtrucknwheels

Yeah i misplaced the decimal. My bad.

ewong

Some later speedos are "electric" (i.e. no cable to the cluster), theres a VSS bolted to the xfer case where the speedo cable would plug in

bigtrucknwheels

Yeah his is an electric. Durr! I think the electric was integrated in 92 or 93. Somewhere in there.

frodin1

Not real sure about applicable years, but here you go http://www.performanceproducts4truck...=10&pid=110230