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Discussion Starter · #1 ·
I recently bought an 86 turbo z cs as my first car.A buddy of mine is showing me the works and such of the car however I have what I believe to be an electrical problem with the tps.the car is throwing code 24 and 44 however I followed the directions and checked the grounds and dcs of the connectors,logic module and the sensor itself and it all seems to be in order.I even replaced the sensor (even though the previous one seemed fine) just in case ,however the sensor seems fine.But the power limited light is still on.the car goes above 2k rpm so I don’t believe it is in limp in mode,and I’m not sure what to check next.I read somewhere to check vacuum lines and the wastegate,however I’m not sure if these are even related.I apologize for my incompetence at wording this correctly lol.Any ideas for what to try next?Thank you very much in advance for any help :)).
 

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Code 24 could be TPS Voltage Low (Closed Throttle below .20 volts) or TPS Voltage High (Closed Throttle above 4.80 volts), only a scanner will tell you which is the case, however all you need is a digital voltmeter.
There are 3 wires for the TPS...
OR/WT (Orange/White) 5 volt reference
OR/DB (Orange/Dark Blue) Signal Line
BK/LB (Black/Light Blue) Signal Return Line (Internal Controller Ground)

Using your digital voltmeter backprobe the Signal and Signal Return Line with the key on.
Closed throttle voltage should be in .30 volts to .90 volts.

Post back and let me know what your closed throttle voltage is so we know if we are working with an open or shorted condition.

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Before hand you should...
1)Check the connectors/terminals at the Logic Module for corrosion or damaged terminals, very common on 85-87 vehicles,
The logic module is located behind the R/S kick panel.
Disconnect and Isolate the - battery cable before disconnecting any controller connectors.
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2)Verify the main controller ground is securely connected to the fuel rail bolt.
Schematic Rectangle Slope Font Parallel
 

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Discussion Starter · #3 ·
Orange and dark blue with throttle closed is approx
.21 dcv
Orange and white with throttle closed is approx 5.08
Black and light blue with throttle closed is approx .04
 

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Orange and dark blue with throttle closed is approx
.21 dcv
Orange and white with throttle closed is approx 5.08
Black and light blue with throttle closed is approx .04
Probing the OR/DB and BK/LB simultaneously = .21 volts?
1)Using a digital voltmeter recheck throttle position sensor output voltage at the LM by backprobing the Red connector cavity 25 and Blue connector cavity 21.
Closed throttle voltage should read the same as it did at the 6 way TPS/AIS connector.
2)Disconnect the TPS/AIS 6 way connector and both LM connectors.
3)Using a digital ohmmeter check each of the 3 TPS wires at the 6 way connector on the harness side for continuity to ground.
If any of the 3 read < 5 ohms, repair that circuit for a short to ground.
4)Using a digital ohmmeter probe the OR/DB and BK/LB simultaneously, does resistance read < 5 ohms.
If yes, repair short circuit between the signal and signal return lines.
 
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