V-8 Vehicle Speed Sensors (VSS), Speedometers, V8 Conversions, Stealth Conversions

Vehicle Speed Sensors - Speedometer Cables

See also Vehicle Speed Sensors - Reluctor Ring and Speedometer Clamp

Stealth Conversions
The Parts Division of JTR (Jaguars That Run)

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Vehicle Speed Sensors for V8 engine swaps

• Download entire Vehicle Speed Sensors chapter (Chapter 12 of our Chevy TBI/TPI manual)
(Adobe Acrobat .pdf — if you need the free Acrobat Reader, go here)

Stealth Conversions began offering aftermarket vehicle speed sensors (VSS) for engine swaps in 1991. The speed sensors are smog legal for engine swaps, and have been issued CARB EO #D-371. Without a VSS, the Chevrolet Fuel Injected engines will not run correctly, and they will not pass a smog test.

Basically, the VSS tells the ECM how fast the vehicle is going. Most people think the VSS is only used for the lock-up torque converter. The VSS is also used to control the EGR valve, the charcoal canister purge valve, the electric cooling fans, idle speed, and air/fuel ratio. This is all explained in the Chevrolet shop manuals.

It must be emphasized that the VSS is used to control the idle speed when the vehicle is moving. Without the VSS, a vehicle may have stalling problems under certain conditions. Needless to say, this is dangerous. Raising the minimum idle speed with the adjusting screw can eliminate stalling, but the engine will still not run optimally without a VSS.

A lot of people think that running "closed loop" is best for fuel mileage. Closed loop simply means that the oxygen sensor is being used to monitor the fuel/air ratio. Some of the Chevrolet fuel-injected engines are programmed to run lean under certain conditions (called "highway mode") to improve fuel mileage during steady cruise conditions. Without a VSS, the engine computer (ECM) will not get the correct signals to run the engine for best fuel mileage. There are a lot of programs in the ECM that depend on the VSS. For best operation, the VSS needs to be connected and functioning.

There are four types of VSS signals required by the engine computer (ECM):
1.	The two-pulse (2000 pulses per mile) square wave (D.C. current or direct current) used on all TBI engines through 1992, all computer-controlled-carbureted engines, and on 1985–1989 TPI engines.
2.	A four-pulse (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.
3.	A 40 pulse per driveshaft revolution speed sensor used on 1993 and newer trucks with automatic transmission, 1994 and newer rear drive cars (Camaro, Corvette, and Caprice) with the automatic transmission.
4.	A 17 tooth per driveshaft revolution speed sensor used on 1993–1997 LT1 engines with the Borg-Warner 6-speed transmission. An 11 tooth reluctor ring is used on 1993 LT1 engines with the Borg-Warner wide ratio (3.35 First gear) 6-speed transmission.

PLEASE NOTE: Our manual goes into greater detail on this topic! We regret that we are unable to enter into telephone or e-mail discussions concerning it, as we just cannot spare the time!

Vehicle Speed Sensor, VSS, Speed Sensors, Speedometer, V8 Conversions, V-8 Conversion

5 Vehicle Speed Sensors Offered by Stealth Conversions.(more details below.)

1. Speed Sensor, # 2PRS. $107. including shipping
2.Speed Sensor, # 2PRS-TOY, $132. including shipping
3. Speed Sensor, # 4PAC, $104. including shipping
4. Speed Sensor, # 4PAC-TOY, $135. including shipping

Stealth Conversions Vehicle Speed Sensors
— from book: Chevrolet TPI & Engine Swapping

Stealth Conversions has several types of vehicle speed sensors designed for easy installation into vehicles that were not equipped with vehicle speed sensors. All Stealth Conversions VSS units have CARB EO numbers (#D-371) — they are smog legal for engine swaps.

Shown above are:

1.	Part #2PRS. The two-pulse square wave unit for all passenger car TBI installations, all computer controlled carbureted engines, and 1985-1989 TPI engines. 7/8-18 thread, .104" square drive.	4.	Part # 4PAC-TOY. Four-pulse sine wave for Toyota with 22 mm metric thread and .187 tang drive
2.	Part # 2PRS-TOY.Two-pulse for Toyota. Same as above, except for 22 mm metric threads, and .187 tang drive which fits Toyota transmissions and transfer cases.	5.	Part # 2X90. Dual output 90° angle drive. Use on Jaguars with electric speedometers. Allows connecting Jaguar XJ-S transducer on one end to operate Jaguar speedometer, and connecting two-pulse or four-pulse unit on other end for Chevrolet ECM. XJ-6 Jaguars must use tranducer from XJ-S.
3.	Part # 4PAC. Four-pulse sine wave.

Two other speed sensors we sell are pictured below (click links for details):
6.	4PAC Integral Sleeve (Passenger Car Speed Sensor, 4-pulse integral VSS/speedometer sleeve), Used with 700 R-R4 Transmission		7.	OEM stock sensor (GM part # 15547452, used on 1989 and newer 4X4 trucks)

4-pulse integral VSS/speedometer sleeve

Passenger Car Speed Sensor, 4-pulse integral VSS/speedometer sleeve, Used with 700 R-R4 Transmission, # 4PAC Integral Sleeve.
$101,including shipping

Includes gears: drive gear (15, 17, 18 tooth), driven gear (34–45 tooth), sleeve, o-ring, retainer.
Specify tire size and rear axle ratio.

PASSENGER CAR VEHICLE SPEED SENSORS

On the far right above is a 4-pulse integral VSS/speedometer sleeve. This VSS has provisions for using a standard speedometer cable and was used on 1990-1992 Police cars which had cable driven radar units. The unit is no longer available from Chevrolet, but Stealth Conversions has a large inventory of the remaining units. This will work for a 1990-1992 TPI (or 1990-1992 Camaro V6) and 1992-1993 LT1 engine with a 700-R4 transmission or ZF six-speed into a vehicle which requires a mechanical speedometer. This unit comes in two styles: one for 34-39 tooth driven gears, and one for 40-45 tooth driven gears. They use the same speedometer gears as the Corvettes and Camaros. This unit will also trigger the 4-output vehicle speed buffer shown on page 12-2 of the VSS chapter. This unit is made of plastic, and will not support an angle drive unit.

stock sensor (GM part £ 15547452) and pigtail (aftermarket part, replaces GM £ 12085498

Stock sensor (GM part # 15547452), shown with "pigtail" connector

Stock GM Speed Sensor, GM # 15547452, New OEM, $50, including shipping
"Pigtail" (connector replacement pack, for GM speed sensors), aftermarket, $15. including shipping

Stock GM sensor

The picture above gives a closer view of the stock sensor (GM part # 15547452), used on 1989 and newer 4X4 trucks. It is shown with the wiring connector, or "pigtail" (an aftermarket part, equivalent to GM part # 12085498), and compared to the modified speed sensor. You can modify the speed sensor yourself if you are good with a soldering iron.

NEW Toyota FJ-40 reluctor ring kit

This kit bolts to rear of the transfer case, and provides the proper vss signal for the 1993 and newer Chevrolet engine. Kit includes vss, reluctor ring, and rear cover assembly.

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JTR engine swapping manuals are available directly from JTR Publishing,
As well as through a number of retailers, including:
• Summit Racing (S-10: Part #JTR-S10; Jaguar: Part #JTR-JAG),
• JEGS (S-10: Part #116549; TPI & TBI: Part #117942),
• Steve Smith Autosports (S-10: Part #S212; TPI & TBI: Part #S195), and
• Classic Motorbooks (S-10: Part #116549; TPI & TBI: Part #117942;
Jaguar: Part #118438; Datsun Z: Part #115501; Volvo 200: Part #122587).

last updated 02/17/2016