The speedometer in my 94 SS reads way too fast. Started noticing when I thought I was 'speeding' and everyone on the highway was passing me -- still! Next cue was the stationary radar signs with speed readout. Lastly, I brought along my handheld GPS unit and compared speeds. When my speedo says 40mph, GPS says 33. When the speedo says 75mph, GPS says 65.
The tires are 195/50/R15, which according to http://www.discounttire.com/dtcs/infoTireMath.dos, should only account for a 1.5-2.5mph speed difference through normal driving speeds.
I've taken out the inner-speedo cable, wiped it down and then relubed it all with lithium grease. Below 25mph, there is a tiny amount of bobbing, but otherwise its stable.
What else could cause such a large discrepancy in the speedometer?
Speedometer reads high
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Speedometer reads high
'11 WRX Limited
'94 SS | 3" TBE, 07 TMIC, TD05H-16G, Revtronix Stage 2, Walbro -- Sold
'94 TW | R.I.P.
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93forestpearl
- Fifth Gear
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- Location: Twin Cities, MN
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fishbone79
- Second Gear
- Posts: 502
- Joined: Fri Sep 03, 2004 3:14 am
- Location: Armpit, USA
On some really cold days I'd casually look down at my speedo on my way to work and find that I'm apparently going 125 MPH through my residential neighborhood.... This is usually accompanied by an audible whirring from the cluster.
I doubt our problems are causally related, but I gave my speedo cable the same treatment as you to no avail. I know the gear assembly in the trans is fine (I put it there when the trans was apart), but perhaps thick oil in the cold AM buggers the gear so it spins too fast. My only other guess is that something is wrong with the assembly in my guage itself (thick, gunky grease?).
I doubt our problems are causally related, but I gave my speedo cable the same treatment as you to no avail. I know the gear assembly in the trans is fine (I put it there when the trans was apart), but perhaps thick oil in the cold AM buggers the gear so it spins too fast. My only other guess is that something is wrong with the assembly in my guage itself (thick, gunky grease?).
Cheers,
morgan
1992 Legacy BF
1946 Ford 1.5 Ton Truck (The Beast): http://community.webshots.com/user/fishbone79
morgan
1992 Legacy BF
1946 Ford 1.5 Ton Truck (The Beast): http://community.webshots.com/user/fishbone79
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93forestpearl
- Fifth Gear
- Posts: 3043
- Joined: Tue Jan 25, 2005 9:14 pm
- Location: Twin Cities, MN
Oh, don't worry about the noise from the speedo when cold, and the super high reading. All three of my first gen legacies have done that. It usually doesn't do it unless it's below ten degrees, When it's 20 below zero, it gets really loud, lol. My three cars, when its really cold, would tell me over 100 mph when I am doing about 30.
→Dan
piddster34 at h0tma1l d0t c0m
piddster34 at h0tma1l d0t c0m
yes, it's not that hard either.BSOD2600 wrote: I wonder if the speedo gauge can be removed from the cluster and transferred over...
Basically, unclip the front plastic cover. Then unscrew the temp and fuel gauages from the back and remove the inner fascia w/secondary guages. Then the speedo can be uscrewed and removed.
I might have pics in my Flickr album.
'93 Winestone SS Auto, '91 Pearl White SS.
'93 Pure White SS EJ20G slanty intercooled, SIDESWIPED! In stasis.
'94 FWD and '95 AWD Laguna Blue SVXs.
2017 Pure Red BRZ Limited w/Performance pack
'93 Pure White SS EJ20G slanty intercooled, SIDESWIPED! In stasis.
'94 FWD and '95 AWD Laguna Blue SVXs.
2017 Pure Red BRZ Limited w/Performance pack
I switched back to stock wheels (195/60 R15) to see how much of a difference it would make. Only some 
. Now when the speedo says 40 mph, GPS says 35. Speedo says 50mph, GPS says ~45.
According to the FSM, these variations are normal:
I assume the +0.9 and +3.9 means it should always read +0.9 to +3.9 over the real speed the car is traveling (while at 40 mph)?
I'm not sure if was due to the 4.11 gearing the the tranny in the TW, which compensated for the inherient speedo tolerances or what, but it was basically dead on for accuracy. I guess when I replace the dead lights in the cluster, I'll swap over the speedo and see how much that helps...
. Now when the speedo says 40 mph, GPS says 35. Speedo says 50mph, GPS says ~45.According to the FSM, these variations are normal:
I assume the +0.9 and +3.9 means it should always read +0.9 to +3.9 over the real speed the car is traveling (while at 40 mph)?
I'm not sure if was due to the 4.11 gearing the the tranny in the TW, which compensated for the inherient speedo tolerances or what, but it was basically dead on for accuracy. I guess when I replace the dead lights in the cluster, I'll swap over the speedo and see how much that helps...
'11 WRX Limited
'94 SS | 3" TBE, 07 TMIC, TD05H-16G, Revtronix Stage 2, Walbro -- Sold
'94 TW | R.I.P.
Yes I believe that is correct.BSOD2600 wrote:I assume the +0.9 and +3.9 means it should always read +0.9 to +3.9 over the real speed the car is traveling (while at 40 mph)?
Josh
surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT
If you need to get a hold of me please email me rather then pm
surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT
If you need to get a hold of me please email me rather then pm
Well now I have other more serious issues with the speedometer. I swapped the speedometer from the TW to the SS cluster -- yes it was working after the crash since I drove it around town for a day. The part numbers on both were the same too.
After getting the dash all put back together, I went for a drive. No speedo movement.... except when I really floor it and then the needle moves sluggishly. I got home, attached a drill to the end of the speedo cable before it goes into the transmission -- speedo seems to move normal. I took out the plastic pieces which screws into the transmission -- that moves/turns just fine too. There are no ECU codes getting thrown either. I already lubed up the cable the other week with lithium grease too.
I made short movies of the drill and driving with these new issues which can be found here.
Any ideas WTF is wrong now?
After getting the dash all put back together, I went for a drive. No speedo movement.... except when I really floor it and then the needle moves sluggishly. I got home, attached a drill to the end of the speedo cable before it goes into the transmission -- speedo seems to move normal. I took out the plastic pieces which screws into the transmission -- that moves/turns just fine too. There are no ECU codes getting thrown either. I already lubed up the cable the other week with lithium grease too.
I made short movies of the drill and driving with these new issues which can be found here.
Any ideas WTF is wrong now?
'11 WRX Limited
'94 SS | 3" TBE, 07 TMIC, TD05H-16G, Revtronix Stage 2, Walbro -- Sold
'94 TW | R.I.P.
Decided to take the dash and cluster apart -- again, GUH!
Did a little test of the two speedometers. Set a constant speed on the drill, attached the speedo cable to the both of them and see how they react. Well no surprise, the one I swapped into my car is very sluggish and doesn't respond to slow speeds. I did happen to take it somewhat apart too, before putting it into the cluster. But since it's purely mechanical, didn't think I could do any harm. My 'old' speedo works well and responds way better, so I guess that one goes back into the car for now -- and I'm still stuck with the speed inaccuracy issues!
Anyways, since the other speedometer is basically 'broken', I decided to take it apart and understand how it works.
After taking off the speedo face (two screws and carefully lifting up on the speedo needle with two screwdrivers), you see the following. That is spring steel, which is wrapped around the speedo shaft and returns the needle back to zero.
On the bottom of the speedo assembly, one finds this piece of plastic with some electronics on the inside. Since this sits very close to the ring/shaft which the speedo cable spins, is this the VSS - vehicle speed sensor?
Once the tripodometer is removed, you get a better picture of the basic components of the speedo meter. The silver disk is directly connected to the back side of the speedo assembly -- this is what the cable spins. The copper turns freely and is directly connected to the speedometer needle. The metal to the left of the shaft is the stopper which holds the copper disk from continously turning as the spring steel loop returns it back.
Inside the copper disk.
Inside the silver disk -- a giant magnet.
So since this is purely a mechanical device, why/how is it that one of my speedos reads very sluggishly when I power it with the drill? The silver and copper disks don't touch, except for that center pin in the copper one, which I believe is just to keep it centered/aligned. This also now makes more sense why the speedos can read 0.9 to 5 mph off, probably due to the magnetic field tolerances.
Did a little test of the two speedometers. Set a constant speed on the drill, attached the speedo cable to the both of them and see how they react. Well no surprise, the one I swapped into my car is very sluggish and doesn't respond to slow speeds. I did happen to take it somewhat apart too, before putting it into the cluster. But since it's purely mechanical, didn't think I could do any harm. My 'old' speedo works well and responds way better, so I guess that one goes back into the car for now -- and I'm still stuck with the speed inaccuracy issues!
Anyways, since the other speedometer is basically 'broken', I decided to take it apart and understand how it works.
After taking off the speedo face (two screws and carefully lifting up on the speedo needle with two screwdrivers), you see the following. That is spring steel, which is wrapped around the speedo shaft and returns the needle back to zero.
On the bottom of the speedo assembly, one finds this piece of plastic with some electronics on the inside. Since this sits very close to the ring/shaft which the speedo cable spins, is this the VSS - vehicle speed sensor?
Once the tripodometer is removed, you get a better picture of the basic components of the speedo meter. The silver disk is directly connected to the back side of the speedo assembly -- this is what the cable spins. The copper turns freely and is directly connected to the speedometer needle. The metal to the left of the shaft is the stopper which holds the copper disk from continously turning as the spring steel loop returns it back.
Inside the copper disk.
Inside the silver disk -- a giant magnet.
So since this is purely a mechanical device, why/how is it that one of my speedos reads very sluggishly when I power it with the drill? The silver and copper disks don't touch, except for that center pin in the copper one, which I believe is just to keep it centered/aligned. This also now makes more sense why the speedos can read 0.9 to 5 mph off, probably due to the magnetic field tolerances.
Last edited by BSOD2600 on Sat May 07, 2016 5:18 am, edited 1 time in total.
'11 WRX Limited
'94 SS | 3" TBE, 07 TMIC, TD05H-16G, Revtronix Stage 2, Walbro -- Sold
'94 TW | R.I.P.
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93forestpearl
- Fifth Gear
- Posts: 3043
- Joined: Tue Jan 25, 2005 9:14 pm
- Location: Twin Cities, MN
Well I'm deeming my speedo fixed. Basically I popped off the needle and the moved it down a bunch -- way below the 0 mph mark. Test drove it with my GPS and past a radar mph sign. Both show its within ~1-2mph at 40 mph now. Good enough.
'11 WRX Limited
'94 SS | 3" TBE, 07 TMIC, TD05H-16G, Revtronix Stage 2, Walbro -- Sold
'94 TW | R.I.P.