1G-FE engine does not start: 12 reasons and step-by-step repair

If Toyota with motor 1G-FE (installed on Mark II X80/X90, Chaser X80/X90, Cresta X80/X90) suddenly stopped starting, first check for sparks on candles and pressure in the fuel rail. A characteristic symptom of a malfunction of this engine is failure to start when the starter is running and there are no errors on the dashboard. In 70% of cases the problem lies in ignition coils, EFE relay (forced idle systems) or crankshaft position sensor. Before sinning on the ECU, rule out mechanical problems: check the compression in the cylinders and the condition of the timing belt - its breakage on the 1G-FE often occurs without warning signs.

Feature 1G-FE — sensitivity to fuel quality and electrical wiring condition. If the engine “seizes” and immediately stalls, the fault is Idle air control valve (ISC) or air leaking through a cracked manifold. If there is complete silence from the fuel pump (no characteristic buzzing when the ignition is turned on), check EFI fuse 15A in the block under the hood and the fuel pump relay. On models before 1996 it often fails ignition module (installed on a bracket behind the block head), which cannot be repaired - only replaced.

1. Diagnosis based on symptoms: what to do if the starter turns, but the engine does not start

When 1G-FE does not start when the starter is working, the verification algorithm depends on the accompanying symptoms. Start with basic tests:

• 🔋 Battery check: The voltage at the terminals must be at least 12.4V (at startup - not lower than 10.5V). On Toyota with 1G-FE, a weak battery can block the operation of the ECU.
• ⚡ Spark on candles: Unscrew the spark plug, insert it into the high-voltage wire and apply it to ground. When cranking the starter, a bright blue spark should appear. If it is not there, the problem is in the coils, distributor or crankshaft sensor.
• ⛽ Fuel in the ramp: press the spool on the fuel rail (next to the injectors). If gasoline does not spray under pressure, the pump is faulty, the filters are clogged, or the EFI relay is burned out.
• 📟 ECU errors: on models with OBD-I (until 1996) errors are read by a jumper in the diagnostic connector (under the hood). For OBD-II (after 1996) a scanner is required.

If there is a spark, fuel flows, but the engine does not catch, check compression. For 1G-FE the normal values are 12–14 bar in all cylinders (dispersion no more than 1 bar). Low compression in one cylinder will indicate a burnt valve or stuck rings. On engines with mileage over 200 thousand km, hydraulic compensators often break down - their jamming can block starting.

⚠️ Attention: On 1G-FE with system VVT-i (after 1998) starting failure may be due to a faulty phase shifter clutch. Check the timing chain - when stretched, it jumps by 1-2 teeth, which throws off the phases.

2. Typical malfunctions of the 1G-FE ignition system

Ignition system 1G-FE built on the basis individual coils (one per pair of cylinders) or ignition module (on earlier versions). Frequent problems:

Malfunction	Symptoms	How to check	Solution
Ignition coil breakdown	Engine troubles, misfires, error P0300–P0306	Swap the coils - if the misfires transfer to another cylinder, the coil is faulty	Replacing the coil (item: 90919-02243)
Crankshaft sensor circuit open	No spark, no signal to tachometer	Ring the wires from the sensor to the ECU (pins 20 and 21 on the connector)	Wiring repair or sensor replacement (90919-02230)
Malfunction of the distributor (distributor)	The engine stalls while driving and does not start after warming up.	Checking the resistance of the distributor coil (should be 0.5–1.5 kOhm)	Replacing a distributor or slider
Short circuit in ignition harness	IGN fuse blows (10A), burning smell	Visual inspection of the harness for melting, testing with a multimeter	Replacing the harness or restoring the insulation

On motors 1G-FE with OBD-I (until 1996) often fails ignition switch (installed under the glove compartment). Its malfunction manifests itself as follows: the engine starts and immediately stalls, or does not respond to the starter at all. Check the voltage at the switch contacts (should be 12V on pin 1 and 5V on pin 4 with the ignition on).

1. Check spark on all spark plugs|false

2. Ring the crankshaft sensor circuit (resistance 800–1400 Ohms)|false

3. Inspect the coils for cracks and signs of breakdown|false

4. Check fuse IGN (10A) and ignition relay|false

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3. Problems with the fuel system: from the pump to the injectors

If 1G-FE does not start due to lack of fuel, the culprit may be:

• ⛽ Fuel pump: on models before 1995 a pump was installed 23220-20010prone to overheating. Symptom of malfunction - the pump does not buzz when the ignition is turned on.
• 🔌 EFI relay: located in the relay box under the hood (next to the battery). If the engine fails, it does not receive fuel, although the pump can operate.
• 🧹 Clogged fuel filter: on 1G-FE fine filter (23300-20010) becomes clogged after 40–50 thousand km, which leads to “starvation” of the engine.
• 💉 Injectors: If the engine catches but does not hold idle, check the injector resistance (should be 12–16 Ohm).

To diagnose the fuel system:

1. Remove the fuel hose from the rail and direct it into a container. When the ignition is turned on, gasoline should flow out (pressure no less than 2.5 bar).
2. If fuel does not flow, check the voltage at the pump connector (pin 2 - +12V, contact 1 - ground).
3. If there is voltage, but the pump does not work, replace it. On 1G-FE after 1996 a pump was installed 23220-20030 (more reliable).

⚠️ Attention: On Toyota Mark II/Chaser with 1G-FE after 1998 the system is used SFI (sequential injection). If the engine does not start, but fuel is supplied, check the signal from throttle position sensor (must be 0.5V at idle and 4.5V when fully open).

4. Electronics and ECU: hidden reasons for startup failure

Electronic control unit (ECU) on 1G-FE rarely fails, but problems with wiring or sensors can prevent starting. Common faults:

• 📡 Coolant temperature sensor circuit open: The ECU receives incorrect data and over-riches the mixture. The engine may start and stall immediately.
• 🔌 Oxidation of contacts on the ECU connector: This is especially true for machines operated in high humidity conditions. Contacts A10, A20, B15 are responsible for signals from sensors.
• 💻 ECU firmware failure: on engines with OBD-I (before 1996) there may be calibration errors that require re-flashing.
• 🔋 Voltage drop on the +5V line: powers the sensors. Check the voltage at the contact B25 ECU connector (must be 4.8–5.2V).

To check the ECU:

1. Remove the fuse box cover under the steering wheel and locate the ECU (black box with connector).
2. Disconnect the connector and inspect the contacts for corrosion. Clean them up contact spray (for example, CRC 2-26).
3. Ring the power circuit: pin A1 — +12V (constantly) pin A22 — +12V with the ignition on.

How to reset ECU errors on 1G-FE without a scanner

On models with OBD-I (before 1996), errors are cleared by disconnecting the battery terminal for 10–15 minutes. On OBD-II (after 1996), a scanner or diagnostic connector with a jumper for pins TE1 and E1 is required (see diagram in the manual).

If the ECU does not send signals to the injectors (checked with a tester at the injector connector), there are two possible reasons:

1. The ECU itself is faulty — Replacement or repair is required (resoldering of capacitors).
2. Immobilizer lock - on models after 1997, check the synchronization of the key with the ECU (whether the immo light on the panel is blinking).

5. Mechanical faults: timing, compression, valves

If 1G-FE does not start, but the starter turns vigorously, and the spark and fuel are normal, check the mechanical part:

• 🔗 Broken timing belt: on 1G-FE this leads to a collision between the valves and the pistons (the engine “sticks”). Check the integrity of the belt through the cover on the front of the engine.
• 🔧 Rotating the liners: if the engine suddenly stalls and does not turn with the starter (a metallic grinding noise is heard), this is a sign rotation of the main or connecting rod bearings.
• 🌡️ Thermostat stuck in closed position: leads to overheating and deformation of the block head. Check to see if steam is coming from under the hood.
• 🔩 Loose timing chain: on motors with a chain drive (after 1998), a stretched chain can jump 1-2 teeth, knocking out the phases.

To check compression you will need a compression gauge. Algorithm:

1. Unscrew all spark plugs.
2. Insert the compression gauge into the first cylinder.
3. Crank the engine with the starter (5–7 seconds). Record your readings.
4. Repeat for all cylinders.

Compression readings	Diagnosis	Actions
12–14 bar (range up to 1 bar)	Norm	Look for the cause in the electronics or fuel system
Below 10 bar in one cylinder	Valve burnt out or rings stuck	Measure the pressure with oil (pour 5 ml into the cylinder). If it has grown - rings, if not - valves
Below 8 bar in all cylinders	CPG wear or cylinder head gasket burnt out	Engine disassembly, ring/gasket replacement
Variation of more than 2 bar between cylinders	Uneven wear of the CPG	Diagnostics on the stand, major repairs possible

⚠️ Attention: On 1G-FE with mileage over 250 thousand km it often bursts plastic intake manifold (especially on supercharged versions 1G-GTE). A crack leads to air leaks and startup failure. Inspect the manifold for cracks near the throttle valve.

6. Diagnostics by error codes (OBD-I and OBD-II)

On 1G-FE two diagnostic systems are used:

• OBD-I (before 1996) — errors are read by blinking light CHECK ENGINE (jumper in diagnostic connector).
• OBD-II (after 1996) - a scanner is required (for example, ELM327).

Decoding common errors for 1G-FE:

Error code	Description	Possible reason	Solution
12	No signal from crankshaft position sensor	Open circuit, faulty sensor or gear on the crankshaft	Check the wiring, replace the sensor (90919-02230)
14	Coolant temperature sensor malfunction	Short circuit or open circuit in the sensor circuit	Replace sensor (89422-20010), check the wiring
21	Problem with the ignition system	Faulty coil, distributor or switch	Checking the spark, replacing faulty elements
24	Intake air temperature sensor signal low	Sensor (89422-20030) or open circuit	Replacing the sensor, checking the connector
41	Throttle Position Sensor Malfunction	Wear of the resistive layer or contamination of the throttle	Cleaning the throttle, replacing the sensor (89452-20010)

To read errors on OBD-I:

1. Locate the diagnostic connector (usually under the hood, next to the battery).
2. Jumper the contacts TE1 and E1 (on some models - T and E).
3. Turn the key to position ON (do not start the engine).
4. Read codes by flashing light CHECK ENGINE (eg 3 long + 4 short = error 34).

OBD-II scanner|Multimeter|CHECK ENGINE light (on your own)|Contact service-->

7. Step-by-step instructions: what to do if 1G-FE does not start

Follow this algorithm for quick diagnosis:

1. Check the battery:
   • Voltage at the terminals when the ignition is off - 12.4–12.7V.
   • When starting, the voltage should not drop below 10.5V.
2. Make sure there is spark:
   • Unscrew the spark plug, insert it into the high-voltage wire and apply it to ground.
   • Crank the starter - the spark should be bright and stable.
3. Check fuel:
   • Press the fuel rail spool - gasoline should spray out under pressure.
   • If there is no fuel, check the fuse EFI 15A and fuel pump relay.
4. Diagnose sensors:
   • Check the crankshaft sensor (resistance 800–1400 Ohm).
   • Check the signal from the throttle position sensor (should be 0.5V at idle).
5. Rule out mechanical faults:
   • Check the compression (normal - 12–14 bar).
   • Inspect the timing belt/chain for integrity.

8. Common mistakes when repairing 1G-FE

For self-repairs, owners Toyota with motor 1G-FE The following mistakes are often made:

• 🔧 Ignoring timing marks: Even a shift of 1 tooth results in the engine not starting or running intermittently.
• 🔌 Incorrect replacement of ignition coils: on 1G-FE, the coils are connected in pairs (cylinders 1–4 and 2–5). Mixed up wires will lead to misfires.
• ⛽ Using low-quality fuel: Gasoline with an octane rating below 92 will cause detonation and damage the knock sensor (89615-20010).
• 🧹 Changing oil without flushing: on engines with a mileage of over 200 thousand km, deposits in the oil channels can clog the hydraulic compensators, which will lead to knocking and failure to start.
• 🔋 Connecting the battery with the ignition on: this may burn out the ECU or relay.

To avoid problems:

• Always reset ECU errors after repair (by disconnecting the battery or using a scanner).
• Use only original spare parts or analogues with verified catalog numbers (for example, Denso for spark plugs and coils).
• After replacing the timing belt, turn the engine by hand (at the crankshaft bolt) 2 turns to make sure there is no jamming.

FAQ: Frequently asked questions about launching 1G-FE

The engine starts and immediately stalls. What is the reason?

On 1G-FE This is a symptom of a malfunction Idle air control valve (ISC) or air leaking through a cracked intake manifold. Also check:

• Throttle position sensor (should indicate 0.5V at idle).
• Fuel pressure regulator (located on the fuel rail).
• Vacuum hoses for cracks.

If the problem appears after washing the engine, water probably got into the ECU connector - dry it with a hairdryer.

The starter does not turn, but clicks are heard. What to do?

Clicks indicate:

• Discharged battery (voltage below 11.5V).
• Faulty starter relay or oxidized contacts on it.
• Jammed starter (check if it spins when voltage is applied directly).

On 1G-FE also check fuse AM2 30A in the block under the hood - it is responsible for the starter circuit.

How to distinguish a faulty ignition coil from a problem with the ECU?

Symptoms of a faulty coil:

• Misfire in one cylinder (can be detected by sound).
• Error P030X (where X is the cylinder number).
• There is a spark, but weak (yellow, not blue).

Symptoms of a faulty ECU:

• There is no signal to the injectors (checked with a tester).
• All sensors do not work at the same time.
• light bulb CHECK ENGINE does not light up when the ignition is turned on.

For an accurate diagnosis, swap the coils - if the misfires transfer to another cylinder, the coil is faulty. If not, the problem is in the ECU or wiring.

Is it possible to start the 1G-FE from a pusher?

Start up 1G-FE from the pusher not recommended, especially if:

• The VVT-i system is faulty (after 1998) - phases can be lost.
• There is a suspicion of a broken timing belt - this will lead to a valve collision.
• The battery is completely discharged - the generator may not have time to charge the battery.

If you still have to push start:

1. Turn on the ignition.
2. Insert 2nd gear and accelerate the car to 10–15 km/h.
3. Smoothly release the clutch - the engine should seize.

Important: on engines with an automatic transmission, push start is not possible!

What kind of oil should I fill in 1G-FE after a major overhaul?

For 1G-FE after the capital it is recommended:

• Oil type: semi-synthetic or synthetic 5W-30 or 10W-40 (depending on climate).
• Specification: API SG/SH or SL (for engines up to 2000).