Toyota engines - 3S-FE. From dawn to dusk

© Toyota-Club.Net
Jul 2021

3S-FE type'86 · 3S-FE type'90 · 3S-FE type'96

Why do we call 3S-FE the most significant Toyota engine in history, if in 1990s the company produced a lot of successful and interesting engines? Because the legendary inline-6 located under the hoods of too specific RWD Japanese sedans. Because being ideal for compact Corolla-family, the A-series engines weren't enough powerful for cars of a larger class. Because a variety of cheerful -GE and -GTE, mighty UZ and reliable HZ... their total number was not large, and the cost was not suitable for everyone.

It was 3S-FE that allows a lot of owners to feel how at the same time could be sufficient thrust-to-weight ratio and reliability, durability and low-cost, good automatic transmissions and the perfect AWD, good inner space and normal equipment. The 2.0 engine was used in the most necessary classes and sizes - the middle family segment, the first minivans of a modern layout... even the first SUV. It was these cars that raised the bar of a "decent car" in people's feelings to a high, and maybe too high level.

3S-FE lived a fairly long life in the conveyor belt - from 1986 to 2002 (and after the termination of large-scale production, in 2003-2007 the engine was installed in Crown Comfort SXS13 training cars). During this time, it has undergone a number of significant changes that forms three main generations - type'86, type'90 and type'96.

EngineDisplacement, cm3Bore x Stroke, mmCompressionPower, PSTorque, Nm-
3S-FE199886.0 x 86.0 9.3120 / 5600169 / 4400type'86 mod'87
9.3125 / 5600169 / 4400type'86 mod'89
9.5140 / 6000186 / 4400type'90 2WD
9.5135 / 6000181 / 4400type'90 4WD
9.8128 / 5400178 / 4400type'96 EU
9.5124 / 5400178 / 4400type'96 GC
* engine weight 130-140 kg

Application: Avensis 220, Caldina 190..210, Carina E, Carina ED/Corona Exiv 180..200, Corona/Carina 170..190..210, Crown Comfort, Curren, Celica 160..180..200, Gaia, Ipsum/Picnic 10, Nadia, RAV4 10, Townace/Liteace Noah 50, Vista/Camry 20..30..40..50

3S-FE type'86. Sunrise

A new 3S family was born in 1984 with 160-horsepower 3S-GE. But since marketing already demanded the "16 valve" nameplate everywhere, a mass-market engine was created on its basis.

Engine mechanical

The engine had a classic cast-iron cylinder block with a closed deck, generally similar to the block of the first 3S-GE.
Mod'89: The shape of ribs and outer surface of the block has been slightly changed.

The crankshaft is made of cast iron, with 8 counterweights and 5 main journals (medium is wider). Main journal diameter is 55 mm, crank pin - 48 mm, bearing width 19/23 mm.
Mod'89: Flywheel got 8 mounting bolts instead of the initial 6.

The connecting rod has hole for supplying oil to the cylinder wall, the cap fastened with bolts and 6-sided nuts. The diameter of the conrod big-end is 51 mm, of small-end - 20 mm, the distance between the end centers is 138 mm.

The pistons are of light aluminum alloy, with a full-length skirt and a steel reinforcing strip around. The thickness of the piston rings is 1.5/1.5/4.0 mm. Piston pins - non-floating type, installed by pressing into the connecting rods.

The cylinder head is of aluminum, with a "pentroof" type combustion chamber. The bank angle of the valves is only 22.35° - more than two times less than that of the related 3S-GE. With 4 valves per cylinder, the intake and exhaust flow area is more than a quarter larger than of the nominal predecessor 2S-E 8V. At the same time, the width of the -FE head is significantly smaller than that of the -GE motors. The top cover is light-alloy, fastened to the spark plugs tubes.
Mod'89: The cylinder head gasket was changed (due to the fight against asbestos-containing materials), its mounting bolts have become 12-sided, the edge of the combustion chamber has slightly changed.

The valvetrain is DOHC "narrow twincam" type - the belt drives the intake camshaft, from which the exhaust camshaft is rotated by a gear (to reduce noise, the driven gear is scissor-type, with a spring).

Valve timing: intake open 6° BTDC, close 40° ABDC; exhaust open 54° BBDC, close 6° ATDC.
Mod'89: The duration of the exhaust valve open state is noticeably reduced - intake open 6° BTDC, close 40° ABDC; exhaust open 36° BBDC, close 4° ATDC.

Valve dimensions: intake - stroke 6.96 mm, height 100.6 mm, diameter 32 mm, stem 6 mm; exhaust - stroke 7.6 mm, height 100.45 mm, diameter 27 mm, stem 6 mm.

The valve clearance is adjusted using chrome vanadium washers located above the tappets, which eliminates the need to remove the camshafts. The diameter of the tappet was originally 28 mm, washers - 25 mm.

The timing belt also drives the coolant pump and oil pump, and is equipped with a spring tensioner. If the belt breaks, the pistons and valves do not contact each other.

Mod'89: The engine got two hydraulic-type mountings for better vibration damping.

1 - float, 2 - diaphragm, 3 - orifice, 4 - outer ring, 5 - inner ring, 6 - rebound stopper. a - liquid, b - air, c - inner bushing


Trochoid-type oil pump is driven by a timing belt. The nominal pressure is 1.5-2.0 bar, the pressure relief valve is set to 4 bar.

Oil filter is of classic design, with a 700 mm2 nominal filtration area and a valve set to 1 bar.


The system is classic, the thermostat is "cold" (82°) mechanical, the only additional cooled/heated component is the throttle body.
Mod'89: The diameter of the thermostat has been increased from 30 to 35 mm.

1 - thermostat, 2 - throttle valve. a - from heater, b - to heater, c - to radiator, d - from radiator

1 - fan thermo switch, 2 - bypass pipe, 3 - coolant gauge sensor, 4 - cold start injector timer, 5 - EFI coolant temperature sensor. a - from cylinder head, b - to throttle body, 3 - from throttle body, 4 - from heater, 5 - to heater

Intake and exhaust

The intake manifold is cast-made, located on the dashboard side.

The exhaust manifold is of simple old-style shape. The catalyst is made as a separate unit between manifold and front pipe.

Fuel system / Engine control

EFI-D type system - multipoint injection, with return line, with MAP sensor.

1 - neutral starts switch, 2 - vehicle speed sensor, 3 - A/C switch, 4 - ECM, 5 - catalyst overheat lamp, 6 - intake air temperature sensor, 7 - throttle position sensor, 8 - VSV, 9 - injector, 10 - distributor, 11 - igniter, 12 - battery, 13 - starter, 14 - circuit opening relay, 15 - fuel pump, 16 - oxygen sensor, 17 - catalyst temperature sensor, 18 - catalyst, 19 - coolant temperature sensor, 20 - vacuum sensor

The throttle valve is of an outdated type: idle speed under load is maintained by VSV, the basic speed adjusting by screw, the position sensor is a 3-pin discrete type (PSW-IDL-E1).

Mod'89: There are traditional rotary type idle speed control valve (R-ISCV) and 4-pin position sensor with a potentiometer and idle switch.

The outer fuel filter is installed in the fuel line.

Fuel delivery pipe is of aluminum, with vacuum pressure regulator and pulsation damper.

Main injectors - flow rate 185 cm3/min.
Mod'89: Redesigned injectors with a nominal flow rate of 200 cm3/min are slightly lighter.

The early type still had a cold start injector.

The crankcase ventilation system performed as a simple hose between the valve cover and the intake manifold.

EVAP system is of most primitive type without any electronic control.

Sensors are used in the system:
· Intake air temperature sensor
· Coolant temperature sensor
· Oxygen sensor - single (B1S1), zirconium element, switching type
· Exhaust gas temperature sensor (after catalyst)

Ignition system - distributor type, ignition coil built into the distributor (coil resistance ratio 0.42/9000 Ohm), and inductive type sensors NE and G (conventional ersatz of crankshaft and camshaft position sensors). Spark plugs - Denso Q16R-U11 or NGK BCPR5EY11 (at that time considered compact - for 16mm key instead of 20.6mm at previous motors).

Mod'88: The more powerful coil (0.45/12000) and the igniter were moved from the distributor to the dashboard of the engine compartment in most versions.

Self-diagnosis - initiating by jumper wire in the diagnostic connector, used the oldest Toyota 1-digit codes:
1 - Normal
2 - Absolute pressure sensor
3 - Ignition system
4 - Coolant temperature sensor
5 - Oxygen sensor
6 - Speed signal
7 - Throttle position sensor
8 - Intake air temperature sensor
9 - Vehicle speed sensor
10 - Starter signal
11 - Power consumption status (air conditioner / PNP switch)

Mod'89: Flash codes have become the usual 2-digit type
12 - Speed signal (Ne and G)
13 - Speed signal (Ne)
14 - Ignition system
21 - Oxygen sensor
22 - Coolant temperature sensor
24 - Intake air temperature sensor
31 - Absolute pressure sensor
41 - Throttle position sensor
42 - Vehicle speed sensor
43 - Starter
51 - Condition of auxiliaries

Features of European and American versions

• The standard attribute of the overseas 3S-FE is EGR system (version with a control VSV and EVRV).

• Throttle opener - an autonomous vacuum damper, which forces the throttle to close gradually even with a sharp release of the gas pedal, and also leaves the throttle slightly open for a while after the engine is turned off.

3S-FE type'90. Sunshine

Optimal modification, a certain conditional apogee of Toyota's quality.

Differences from the previous type:

• Cylinder block - area for the knock sensor added.

• Connecting rods - big-end diameter increased to 55 mm, cap mounting bolts modified.

• Pistons - the shape of the top was changed, the heat zone was decreased from 7.9 to 5.5 mm, the diameter of the piston pin was increased from 20 to 22 mm. Piston pins - fully floating type (with snap rings).

• Crankshaft - the diameter of the crank journals was increased from 48 to 52 mm.

• Cylinder head - the intake ports received a smoother shape, a separate PCV valve was installed in the cover.

• Camshafts - the cam width was increased from 10 mm to 12 mm, and the stroke of all valves was increased to 7.7 mm. The intake timing shifted and the exhaust timing lengthened: intake open 3° BTDC, close 43° ABDC; exhaust open 45° BBDC, close 3° ATDC.

• Valves - height was decreased to 97.6 mm (intake) and 98.45 mm (exhaust), the springs were changed. The diameters of the tappet and the washer was increased to 31 mm and 28 mm, respectively.

• Cooling: diameter of the thermostat was decreased back from 35 to 30 mm.

• Intake: experiments with the shape of the intake manifold continued to achieve equal channel lengths. Exhaust: the manifold received paired channels, which went into a twin-channel front pipe, while the catalyst moved from the engine compartment to under the bottom (for 2WD versions)

• Ignition: distributor with NE-sensor, new spark plugs - the familiar Denso K20R-U11 or NGK BKR6EYA11

• Control system: there are knock control and, accordingly, a knock sensor - early resonant type. Cold start nozzle was discontinued. Electronic transmission control was implemented.

• A couple of new codes was added to self-diagnostics:
16 - Transmission control
52 - Knock sensor
Mod'91: There are two self-diagnostic modes - normal and test.

• Mod'91: electronically controlled EVAP system with a purge VSV (meanwhile, EVAP with a simple thermal valve widely used at overseas market).

Engine control (type'90 mod'91). 1 - ECM, 2 - starter, 3 - catalyst overheat lamp, 4 - distributor, 5 - vacuum sensor (MAP), 6 - injector, 7 - EVAP VSV, 8 - intake air temperature sensor, 9 - idle switch, 10 - check valve, 11 - canister, 12 - throttle valve, 13 - ISCV, 14 - knock sensor, 15 - oxygen sensor, 16 - coolant temperature sensor, 17 - catalyst temperature sensor

Mod'92: When Japanese decided to attach the optional TRC to 2WD versions, a second throttle valve was added near the usual first one, equipped with its own electric actuator and sensor.

The overwhelming majority of faults in this generation are the result of aging and wear, only sometimes they are aggravated by design mistakes, can be eliminated and practically do not cause sudden breakedowns.

Engine mechanical
• Excessive oil consumption became the norm for ten-years-old engines, but there were plenty of reasons for this:
- Poor oil separation from crankcase gases - pay attention to the PCV valve and oil separator in the valve cover.
- Valve seals (what a pity that endoscopes were not available twenty years ago).
- Piston rings - usually for the first time, the condition of the cylinder block allowed just to replace carbonized and stucked piston rings.
- If the oil does not burn, then it drains out - the S series is known for abundant leaks through all possible oil seals and contact surfaces. Moreover, the old front seals could form such wearing traces on the shafts, along which new ones would no longer be able to provide a sealing.
Often, the elimination of one or two of these points made it possible to reduce oil consumption to an acceptable and non-progressive level, but if necessary, the engines could be successfully overhauled.

• Over time, one way or another, camshaft freeplay develops, but correct repair methods are economically inexpedient - you can only try the DIY-method at your own risk.
And of course, when removing and installing the camshafts, must not forget to fix or adjust the split gear in advance.

• First cases of connecting rod bolt breakage already occurred (usually after re-assembly).

• Unnatural vibrations at normal idle speed indicate engine mountings wear. The practice of step-by-step replacement has shown that without replacing the main hydraulic mounts, there will be no noticeable effect.

• The oil system is not the most successful part of the engine. Firstly, the belt drive is unsuccessful itself - the constant excess load on the timing belt during a cold winter starting with high-viscous oil becomes even higher. Secondly, an extra oil seal and an extra gasket bursting into the area of the timing belt, and this gasket also easily allows wrong installation. Thirdly, in comparison with other engines, issues with oil pressure occur suspiciously often, and subjectively, a pressure warning lamp that does not go out for a long time at startup is perceived as normal.
• Due to the tilt of the engine, the filter needs a good anti-drain valve, although Toyota sells replacement filters that lack this element at all.
• A typical consequence of repairs is pump relief valve contamination with fine debris or sealant particles.
• The end clearance of the pump rotors requires special attention, which greatly affects the performance of the pump - statistics and practice say that during engine overhaul, the oil pump assembly should be preventively replaced.

• Good reliability and efficiency: normal cooling in summer, excellent warming up in winter, the only question is whether to change a yet normal pump every time the timing belt is replaced.

• To the list of age-related oil leaks, add the distributor oil seal and its O-ring, as well as the tubes of the spark plug wells.
• The distributor rotor should be periodically replaces with a new one (instead of sanding off the deposits from the old).

• As all classic engines, the control system is extremely robust in its simplicity. The most frequent questions are "clean the idle speed controller" (ISCV) and "install bosch fuel pump instead of genuine" (previously, "injector cleaning" was always in the top, but apparently over the past 10-15 years the quality of gasoline has really became better).
• Subjectively, do not like the access to the injector zone, which is hampered by the tilted engine, dashboard and intake manifold, and to the block drain plug. But in comparison with semi-bonnet minivans that appeared later, the access was quite easy previously.
• For LHD modifications, the EGR valve should be shut-off to avoid the engine self-poisoning with mix of its own exhaust soot and oil vapors of the crankcase gases.

3S-FE type'96. Sunset

'1996 modification caused irreparable damage to the reliability and durability of the engine mechanical.

• The connecting rod and piston assembly was significantly lightened. Pistons - the skirt was radically reduced (piston became T-shaped in projection), the thickness of the piston rings was reduced (1.2/1.2/3.0); there are four small holes for oil drainage in the oil scraper ring groove (at working sides of the piston) instead of previous eight large holes. Connecting rods - a huge stock of metal has been removed (the thickness of the rod and the small-end was decreased by a third, the width by a quarter). Good full-floating pins were replaced with short press-fitted ones.

• Lubrication: oil pump has undergone some changes.

• Ignition: new DIS-2 type - without distributor and with paired ignition coils, two-contact spark plugs - ordinary Denso K20TR11 / NGK BKREKB11 or "platinum" Denso PK20TR11 / NGK BKREKPB11.

• Intake and exhaust: the catalyst was returned from under the floor to the exhaust manifold to warm up faster and more efficiently, and spider-type exhaust manifolds have become common.

• Control: with the abolition of the distributor, a crankshaft position sensor and camshaft position sensor appeared.

Engine control (type'96 Euro). 1 - ignition switch, 2 - fuel pump, 3 - canister, 4 - return line, 5 - fuel filter, 6 - BVSV, 7 - vehicle speed sensor, 8 - neutral start switch, 9 - DLC3 connector, 10 - A/C amplifier, 11 - check engine lamp, 12 - battery, 13 - electric load signal, 14 - ECM, 15 - igniter, 16 - EGR VSV, 17 - intake air temperature sensor, 18 - throttle position sensor, 19 - ISCV, 20 - MAP sensor, 21 - EGR vacuum modulator, 22 - EGR valve, 23 - knock sensor, 24 - injector, 25 - camshaft position sensor, 26 - oxygen sensor, 27 - catalyst, 28 - crankshaft position sensor, 29 - coolant temperature sensor

• A fuel system version without return line and vacuum regulator, but with a pressure regulator in the fuel pump module (which maintains a constant pressure of 3.3 bar) and new injectors, existed but was not widely used.

• The diagnostic system became available for scanners and acquired modern SAE-codes:
12 / P0335 - Crankshaft position sensor
12 / P0340 - Crankshaft position sensor
13 / P1335 - Crankshaft position sensor
14 / P1300 - Ignition system 1/4
15 / P1310 - Ignition system 2/3
21 / P0130 - Oxygen sensor
21 / P0135 - Oxygen sensor (heater)
22 / P0115 - Coolant temperature sensor
24 / P0110 - Intake air temperature sensor
25 / P0171 - Lean mixture signal
31 / P0105 - Absolute pressure sensor (MAP)
33 / P0505 - Idling regulator
41 / P0120 - Throttle position sensor
42 / P0500 - Vehicle speed sensor
52 / P0325 - Knock sensor
82 / P1645 - Multiplex
- / P0605 - Engine ECU

• There is a new version of FR layout for RWD Townace/Liteace minibuses, as well as the Crown Comfort.

• The main and most serious defect is the breaking of the connecting rod bolts with the subsequent destruction of the engine - is described in this article. It is still impossible to explain or predict the breakdown, as well as to understand why bolts with the same number began to break so often at type'96 engines. The only preventive solution is to never reuse connecting rod bolts.

• The lifetime of high-voltage wires has decreased by half, and a previously unusual problem of ignition coils burn-out appeared.

• The consecuences of piston reshape:
- pistons began to knock at TDC at absolutely small mileage, by the standards of the previous 3S;
- significant wear of pin-piston contacting surfaces began to develop, aggravated by coking of the oil holes in the lugs;
- if not deep scratches, then obvious abrasions on the piston skirts and cylinder walls began to be noted;
- the tendency to coke rings and the oil burning has radically increased.
Well, the only result of the "modernization" was a "phenomenal" fuel economy - about 300-400 cc per hundred km.

Actually, this is where the success of Toyota in the two-liter class ended. Already in 1996, in parallel with the deteriorated 3S-FE, they released the worst engine in the history of the company - 3S-FSE. The company entered the 2000s with a mediocre 1AZ-FE and a completely unsuccessful 1AZ-FSE. By the early 2010s, Toyota could only offer the relatively allowable (against the background of its predecessors) 3ZR-FE and its more problematic brother 3ZR-FAE, soon reaching the chinese 6AR-FSE. The 2020s began with the arrival of the new dark horse, M20A-FKS.
But in addition to more or less serious technical issues, stifling environmental standards and the growing mass of cars led to the fact that none of the new atmospheric two-liters could no longer give feeling of natural power and confident acceleration that the good old 3S provided.

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