Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1990 Mazda MX-5 Miata StandardFACTORY OEM SERVICE PROCEDURE
Throttle Position Sensor (TPS)
NOTE:
On RX7, see ADJUSTMENTS
article for TPS specifications.
TPS VOLTAGE - B2200 (PFI), B2600i, MPV (4-CYL.), MX-6 & 626
| RED Wire Voltage | BLUE Wire Voltage Closed Throttle | BLUE Wire Voltage Wide Open Throttle |
|---|---|---|
| 4.50-4.59 | .37-.54 | 3.58-4.23 |
| 4.60-4.69 | .38-.55 | 3.66-4.32 |
| 4.70-4.79 | .39-.56 | 3.74-4.41 |
| 4.80-4.89 | .40-.57 | 3.82-4.51 |
| 4.90-4.99 | .40-.58 | 3.90-4.60 |
| 5.00-5.09 | .41-.60 | 3.97-4.70 |
| 5.10-5.19 | .42-.61 | 4.05-4.79 |
| 5.20-5.29 | .43-.62 | 4.13-4.88 |
| 5.30-5.39 | .44-.63 | 4.21-4.98 |
| 5.40-5.49 | .44-.64 | 4.29-5.07 |
| 5.50 | .44-.66 | 4.29-5.17 |
TPS CONTINUITY TEST
| Condition (1) | Continuity Between IDL & "E" | ||
|---|---|---|---|
| .004" (.1 mm) | Yes | ||
| .024" (.6 mm) | No | ||
|
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TPS INSPECTION
| Condition (1) | Continuity Between IDL & "E" | Continuity Between POW & TL | |||
|---|---|---|---|---|---|
| Miata | |||||
| .016" (.4 mm) | Yes | No | |||
| .027" (.7 mm) | No | No | |||
| Wide Open Throttle | No | Yes | |||
| Protege & 323 | |||||
| .004" (.1 mm) | Yes | No | |||
| .039" (1.0 mm) | No | No | |||
| Wide Open Throttle | No | Yes | |||
|
|||||
TPS RESISTANCE
| Application | Ohms | ||
|---|---|---|---|
| MPV (V6) & 929 (SOHC) | |||
| Terminals "A" & "D" | 3500-6500 | ||
| Terminals "B" & "D" | |||
| Closed Throttle | 300-1000 | ||
| Wide Open Throttle | 3500-6500 | ||
| 929 (DOHC) | |||
| Terminals "A" & "D" | 3000-6000 | ||
| Terminals "B" & "D" | |||
| Closed Throttle | 200-600 | ||
| Wide Open Throttle | 3300-7000 | ||
TPS ADJUSTMENT TESTS
| Condition (1) | Continuity Between "C" & "D" | |||
|---|---|---|---|---|
| MPV (V6) & 929 (SOHC) | ||||
| .02" (.5 mm) | Yes | |||
| .028" (.7 mm) | No | |||
| 929 (DOHC) | ||||
| .004" (.1 mm) | Yes | |||
| .012" (.3 mm) | No | |||
|
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Factory Service Tools
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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