Speedometer problem(NOT TIRE SIZE), ideas? - Diesel Bombers



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Old 03-25-2013, 06:19 AM
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Default Speedometer problem(NOT TIRE SIZE), ideas?

Hi guys, cant seem to find ANY info on my issue ANYWHERE on the 'net... regardless of make/model even...

My 94 ram speedo is reading approximately double,(ie, says 60-70 in town doing 30-35 via GPS), odo SEEMS to be close to right, i'm going to check it tomorrow though... just forgot too(only been in-town driving).

-truck has a good VSS sensor, just installed a new one and no difference.
-dash cluster works well(I think..), all gauges/lights function.
-gears are good in t-case, both drive and driven(31 tooth/dark green).

the signal voltage going to the sensor is ~11.5 volts, ground seems good, i tested this with a $5 harbor freight digital multimeter, so numbers will be *close*... but voltage seems too high(imho), but the FSM says NOTHING, and the PDP only says to confirm voltage OVER 7VDC... says nothing anywhere about excessive voltage, PCM should be putting 8v to the sensor... (pin 7 I think??)

I have looked over the wiring and haven't seen any obvious cuts/wear/shorts, i'm willing to check anything again... I am hoping its not a dead/faulty PCM or cluster, they are too expensive to buy "just to check".. but I am willing if i can find evidence of failure...

I really want this fixed, and would appreciate info, thanks guys!

if anyone wants or needs info from the PDP or FSM i have both available to scan and upload images or details... ("94" yellow covers)
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Old 03-25-2013, 04:09 PM
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Do you know anyone with a Dodge you can swap clusters with to see if thats the problem ?
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Old 03-25-2013, 04:25 PM
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Quote:
Originally Posted by tiremann9669 View Post
Do you know anyone with a Dodge you can swap clusters with to see if thats the problem ?
no luck there, all my friends seem to drive toyota's

a wrecking yard 50 miles away has a cluster, but its $250, and has 99k miles on it, my trucks got 270k on the clock.

I'm going to check the local ads though, maybe craigslist will deliver...
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Old 03-26-2013, 09:22 AM
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You pull auto parts is the way to go, no way I'd pay 250 for a cluster especially when you're not sure if thats your problem. Try posting for one in the want to buy used section.
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Old 04-03-2013, 08:08 PM
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Well, just did a road trip to laughlin... odometer is dead on correct... compared with road markers and GPS...

it HAS to be the speedo unit inside the cluster itself, the speedo and the odometer run from the same signal input from the vss sensor...

i think the voltage excess isnt going to affect anything.. maybe the longevity of the vss or other sensor... hhhhmmmm i'll worry about that if/when it dies, its a stick, don't need any of this crap to drive it...

on to a wrecking yard to get a cluster, its gonna look funny with a 6k tach and empty auto shift indicator... posted a wtb ad just in case...
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Old 04-04-2013, 12:27 AM
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Don't change the whole cluster just the speedo. I changed one out of a gas burner works fine. Leave the cover off get on a good straight road with gps and stick the needle on at what ever speed you are at. My speedo is right on. I even changed from 245 to 265 tires pulled the needle and reset it, still correct even though the odometer is low 2%.
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Old 04-04-2013, 01:03 AM
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The speedo goes all the way back to zero... I don't see how moving the needle will accomplish anything... The speedo moves throughout the entire range... Points at 5 when I'm barely moving, 10 when I'm doing 5, all the way to pointing almost straight down when I'm doing75-80...
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Old 04-04-2013, 10:34 PM
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Wasn't saying do do it with yours, you said the VSS was OK so it must be your speedometer. Was saying to get another speedo, but you have to pull the needle to get it out, and was telling how to get it back in the correct spot.

But it might be worth trying, doesn't cost anything just a little time.

Last edited by Torkjunky; 04-04-2013 at 10:52 PM.
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Old 04-05-2013, 10:36 AM
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Or just find a diesel cluster and it will have the right tach
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Old 08-29-2013, 01:40 AM
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did you figure out if it was the cluster that was bad?? i have the same issue
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