No speedo
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No speedo
Hey guys I have a 92 Camaro 5.0L TPI 5 speed. A while ago my speedometer stopped working so I took the dash apart (thinking it was cable driven) only to find it's electronic. I'm not sure how the electric speedo's work but could someone give me a few suggestions?
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From: Arlington, Tx
Car: 91 Camaro RS
Engine: empty bay (for now)
Transmission: Built T-56
Axle/Gears: 3.42 stock posi disc
Re: No speedo
The VSS (Vehicle Speed Sensor) is located on the trans and sends an electric signal to the ECM, which sends a signal to your speedometer do drive it. If the VSS goes bad or the wires come loose/get cut/burnt/melted, your speedo will stop working.
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From: Arlington, Tx
Car: 91 Camaro RS
Engine: empty bay (for now)
Transmission: Built T-56
Axle/Gears: 3.42 stock posi disc
Re: No speedo
Its on the transmission tail shaft. I don't know of anyway to test one, but they aren't hard to replace. Just unplug the connector and it just 1 bolt holding it in.
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iTrader: (1)
Joined: Mar 2007
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From: Arlington, Tx
Car: 91 Camaro RS
Engine: empty bay (for now)
Transmission: Built T-56
Axle/Gears: 3.42 stock posi disc
Re: No speedo
You can always do the paperclip trick to see if your ECM is throwing a code for the VSS.
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From: Mooresville NC
Car: LOWERED ♦ CRIMSON METALFLAKE
Engine: ► 400 KUBES ◄
Transmission: 765R4
Axle/Gears: EATON POSI 4.56
Code Breaker
Code 24 can be set in ways other than a VSS failure.
Does the odometer work?
If you have cruise control, does it work?
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Happy Racing!
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Does The White Flag Mean He’s Surrendering?
.
Does the odometer work?
If you have cruise control, does it work?
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
Happy Racing!
◙◙◙◙◙◙◙◙◙◙◙◙◙◙◙
Does The White Flag Mean He’s Surrendering?
.
Thread Starter
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Re: No speedo
Alright so we took the VSS out and it appears to be fine and works properly. However, we recently discovered that although it has the vin code for a 1992 TBI, the previous owner converted it to TPI using a ECU from an 1987. We took the dash apart and found the ECU and a buffer, but from what I've read, the TPI motors are not supposed to have buffers. What do I do now?
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Joined: Mar 2007
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From: Arlington, Tx
Car: 91 Camaro RS
Engine: empty bay (for now)
Transmission: Built T-56
Axle/Gears: 3.42 stock posi disc
Re: No speedo
you can take the wires from the vss going to the buffer, and wire them into the appropriate pin on the computer.
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Joined: May 2006
Posts: 39
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From: CT
Car: 92 Camaro RS, 04 Dodge RAM
Engine: 305 TPI / Hemi 5.7L
Transmission: 5 speed / 4x4 auto
Re: No speedo
Taken from the above article....
VEHICLE SPEED SENSORS:
1. The two-pulse (2000 pulses per mile) square wave (D.C current or direct current) VSS are used on all TBI engines thru 1992, all computer-controlled-carbureted engines, and on 1985-1989 TPI engines.
2. A four-pulse VSS (4000 pulses per mile) sine-wave (A.C. current or alternating current) signal is required by the 1990-1993 TPI, 1992-1993 LT1 engines, and 1990-1993 Camaro 3.1/3.4 V6 engines.
1. The two-pulse (2000 pulses per mile) square wave (D.C current or direct current) VSS are used on all TBI engines thru 1992, all computer-controlled-carbureted engines, and on 1985-1989 TPI engines.
2. A four-pulse VSS (4000 pulses per mile) sine-wave (A.C. current or alternating current) signal is required by the 1990-1993 TPI, 1992-1993 LT1 engines, and 1990-1993 Camaro 3.1/3.4 V6 engines.
I have been working with YoungCamaro92. Since we are looking at a 92 RS TBI that has been converted to an 87-88 TPI with the 1227165 ECM. The 2000 PPM VSS Part#10456087 is the same in all 3 years setups and is functioning. We traced the 2 wires (Pink and Yellow) from the VSS to the buffer and the tested fine. So we know the signal is reaching the buffer. So I think the problem is the stock RS "output vehicle speed buffer". Can anyone tell us if the 87-88 TPI ECM even requires a VSS buffer? If it is required, how do you tell whether it is a 2 pulse (2000 PPM) or a 4 pulse (4000 PPM) buffer? The RockAuto.com website doesn't even carry a part for the buffer for any camaro year.
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iTrader: (1)
Joined: Mar 2007
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From: Arlington, Tx
Car: 91 Camaro RS
Engine: empty bay (for now)
Transmission: Built T-56
Axle/Gears: 3.42 stock posi disc
Re: No speedo
TPI ECMs dont use the buffer, they accept the raw VSS signal from the trans. Thats most likely where the problem is. Unhook the VSS from the buffer and wire it directly to the ECM.
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Joined: May 2006
Posts: 39
Likes: 1
From: CT
Car: 92 Camaro RS, 04 Dodge RAM
Engine: 305 TPI / Hemi 5.7L
Transmission: 5 speed / 4x4 auto
Re: No speedo
Thanks travis401. I found the wiring diagrams at Austinthirdgen.com so we are good to go. We'll keep you posted.
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