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.
Fuel Injector Resistance - Miata
- Resistance Inspection
Disconnect fuel injector 2-pin harness connector. Using ohmmeter, measure resistance between fuel injector terminals. See FUEL INJECTOR RESISTANCE SPECIFICATIONS table. If fuel injector resistance is as specified, check for open or short circuit, go to next step. If fuel injector resistance reading is not as specified, replace faulty fuel injector(s) as necessary. - Open Circuit Inspection
Check for continuity between following terminals:- GND circuit - No. 1 cylinder fuel injector harness connector terminal "B" and PCM 17-pin harness connector terminal No. 2A (Yellow/Black wire).
- GND circuit - No. 2 cylinder fuel injector harness connector terminal "B" and PCM 17-pin harness connector terminal No. 2D (Violet/Green wire).
- GND circuit - No. 3 cylinder fuel injector harness connector terminal "B" and PCM 17-pin harness connector terminal No. 2G (Yellow/Red wire).
- GND circuit - No. 4 cylinder fuel injector harness connector terminal "B" and PCM 17-pin harness connector terminal No. 2J (Yellow/Green wire).
- Power circuit - No. 1 cylinder fuel injector harness connector terminal "A" (Green/Blue wire) and main relay 4-pin harness connector terminal "D" (White/Blue wire) through common connector.
- Power circuit - No. 2 cylinder fuel injector harness connector terminal "A" (Green/Blue wire) and main relay 4-pin harness connector terminal "D" (White/Blue wire) through common connector.
- Power circuit - No. 3 cylinder fuel injector harness connector terminal "A" (Green/Blue wire) and main relay 4-pin harness connector terminal "D" (White/Blue wire) through common connector.
- Power circuit - No. 4 cylinder fuel injector harness connector terminal "A" (Green/Blue wire) and main relay 4-pin harness connector terminal "D" (White/Blue wire) through common connector.
If continuity is present, go to next step. If continuity is not present, repair open circuit in suspect wire or replace wire harness. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS.
- Short Circuit Inspection
Check for continuity between following:- No. 1 cylinder fuel injector harness connector terminal "B" and PCM 17-pin harness connector terminal No. 2A (Yellow/Black wire) to ground.
- No. 2 cylinder fuel injector harness connector terminal "B" and PCM 17-pin harness connector terminal No. 2D (Violet/Green wire) to ground.
- No. 3 cylinder fuel injector harness connector terminal "B" and PCM 17-pin harness connector terminal No. 2G (Yellow/Red wire) to ground.
- No. 4 cylinder fuel injector harness connector terminal "B" and PCM 17-pin harness connector terminal No. 2J (Yellow/Green wire) to ground.
If continuity is present, repair short circuit in suspect wire or replace wire harness.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
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.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
No obligation. See pricing before you book.