Mazda MX-5 Service Manual
1994 Mazda MX-5 Miata
1994 Mazda MX-5 Miata
D - ADJUSTMENTS 1994 ENGINE PERFORMANCE Mazda - On-Vehicle Adjustments
D - ADJUSTMENTS 1994 ENGINE PERFORMANCE Mazda - On-Vehicle Adjustments
D - ADJUSTMENTS
1994 ENGINE PERFORMANCE Mazda - On-Vehicle Adjustments
ENGINE MECHANICAL
Before performing any on-vehicle adjustments to fuel or ignition systems, ensure engine mechanical condition
is okay.
VALVE CLEARANCE
NOTE: All piston engines are equipped with hydraulic valve lash adjusters. Valve
clearance is not adjustable.
IGNITION TIMING
NOTE: Before adjusting ignition timing, warm engine to normal operating temperature.
Turn off all accessories. Place transmission in Neutral (M/T) or Park (A/T).
Ensure idle speed is correct. See IDLE SPEED under IDLE SPEED & MIXTURE. If
timing is not within specification, loosen distributor or Crank Angle Sensor
(CAS) lock bolt. Rotate distributor or CAS until timing marks are aligned.
Tighten lock bolt.
1994 Mazda MX-5 Miata
D - ADJUSTMENTS 1994 ENGINE PERFORMANCE Mazda - On-Vehicle Adjustments
Courtesy of MAZDA MOTORS CORP.
NOTE: On Miata, use Blue 1-pin connector near airflow meter as a source of battery
power for positive lead of tachometer or timing light (battery is in trunk). DO
NOT ground this connector, or 20-amp WIPER fuse will blow.
1. Connect Diagnostic Tester (49 B019 9A0) to diagnostic connector and select SELF-TEST mode (position
1), or connect jumper wire between diagnostic connector terminals TEN and GND. See Fig. 2 .
2. Connect timing light. Set timing to specification. See IGNITION TIMING SPECIFICATIONS table.
See Fig. 1 . Disconnect diagnostic tester or jumper wire from diagnostic connector.
Fig. 2: Diagnostic Connector Terminal ID (Miata)
1994 Mazda MX-5 Miata
D - ADJUSTMENTS 1994 ENGINE PERFORMANCE Mazda - On-Vehicle Adjustments
Courtesy of MAZDA MOTORS CORP.
IGNITION TIMING SPECIFICATIONS
Application M/T
Miata
(2)
(1)
Place automatic transmission in Park.
(2)
Connect jumper wire between terminals TEN and GRN of diagnostic connector.
10 @ 850 10 @ 800
(1)
A/T
IDLE SPEED & MIXTURE
NOTE: Mixture adjustment is NOT a normal tune-up procedure. DO NOT adjust mixture
unless mixture control unit is replaced or vehicle fails emissions test.
NOTE: Idle mixture is not adjustable. If idle mixture is incorrect, see TESTS W/CODES
article in the ENGINE PERFORMANCE section.
IDLE SPEED
NOTE: Before adjusting idle speed, warm engine to normal operating temperature.
Turn off all accessories. Place transmission in Neutral (M/T) or Park (A/T).
Ensure ignition timing is adjusted. See IGNITION TIMING .
NOTE: On Miata, use Blue 1-pin connector near airflow meter as a source of battery
power for positive lead of tachometer or timing light (battery is in trunk). DO
NOT ground this connector, or 20-amp WIPER fuse will blow.
1. Connect Diagnostic Tester (49 B019 9A0) to diagnostic connector and select SELF-TEST mode, or
connect jumper wire between diagnostic connector terminals TEN and GND. See Fig. 2 . Connect
tachometer to diagnostic connector terminal IG (-).
2. If idle speed is not within specification, rotate idle air adjusting screw on throttle body. See IDLE SPEED
SPECIFICATIONS table. Disconnect jumper wire.
IDLE SPEED SPECIFICATIONS
Application M/T: RPM
Miata
(2)
(1)
Place automatic transmission in Park.
850 800
(1)
A/T: RPM
(2)
Connect jumper wire between terminals TEN and GRN of diagnostic connector.
THROTTLE POSITION (TP) SENSOR
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