How to override speed sensor in 91 Z28 305 TPI
#2
Supreme Member
Joined: Jul 1999
Posts: 1,335
Likes: 2
From: Tucson, AZ, USA
Car: '92 Z28; Dk Teal; Her Pkg
Engine: 305
Transmission: Richmond 6 Spd
Axle/Gears: Moser 9", Detroit Locker, 3.70
The difference between the TBI & TPI setup is the speed buffer. The TBI ECM has an external speed buffer & the TPI has the speed buffer built into the ECM. You could do 1 of 2 things. The most desirable way to proceed would be to reprogram the PROM to increase the set point of the speed limiter - see the PROM board for details - or purchase an aftermarket PROM with the speed limiter disabled - Fuel Injection Specialties in TX will do one for $100 to $200 - there are a number of companies to choose from. Another thing to try is disconnecting the VSS inputs to the ECM - I don't know how the motor would run, though, and would not make it a permanent mod.
Tim
Tim
#3
Joined: Jul 1999
Posts: 10,947
Likes: 21
From: Orange, SoCal
Car: 1990 Pontiac Trans Am
Engine: 355 TPI siamesed runners
Transmission: Tremec T56
Axle/Gears: 12-Bolt 3.73
Speed Density TPI needs the VSS sensor to make its calculations, so disabling it will confuse the computer. Your best bet is to get a new chip.
------------------
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-
------------------
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-
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