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M104.98x Motor Swap in a 190E
One of the most common engine swaps for a 190E is the installation of the bigger M103 3.0L motor. The swap from the smaller 2.6L M103 to a 3.0L M103 is a direct bolt-on swap (assuming the engines from the same cutoff years are used) and gives a small increase of around 30HP. Another option is to swap in the CIS version of the M104 engine found on the earliest M104 powered cars (1990-1992 300CE and 1990-1993 300SL). The injection system is still CIS and the ignition system is still EZL, but additional work is required to make the swap complete.
Time | 10 hours |
---|---|
Cost | |
Difficulty | |
Parts Required | |
Applicable models | W201 (specifically 1992-1993 190E 2.6, other models need adaptation) |
Original M103 Engine Removal
- Disconnect battery
- Remove front bumper
- Remove air filter
- Remove upper radiator support
- Vacuum lines
- EGR, 2 lines
- Smog pump
- EZL
- Check valve at driver fender
- Two at the rear of intake manifold
- Black striped white vacuum line for throttle body
- Brake booster line
- Cooling System
- Drain and remove radiator
- Disconnect water heater lines
- Supply at passenger fender
- Return at rear lifting hook
- Remove overflow pipe to coolant reservoir
- AC System
- Vacuum AC system and remove condenser
- Wiring under both headlights and loom ties
- Bolt on driver side securing pipe to chassis
- Disconnect AC hose on driver fender
- Power steering
- Siphon/extract power steering fluid
- Disconnect supply and return lines on pump
- Disconnect fuel lines
- Supply at fuel distributor, 2x 17mm
- Return behind ignition coil, 17mm and 14mm
- Disconnect throttle cables
- Disconnect main engine wiring and set aside
- 4 prong CIS
- 1 prong temperature sensor
- 2 prong temperature sensor
- Cold start valve
- EHA
- Idle microswitch
- Airflow potentiometer
- IACV
- AC compressor
- Throttle position switch
- Ground wire at intake
- 2 plugs at the EZL
- Disconnect auxiliary wiring and set aside
- Oil level sensor
- Oil pressure sensor
- Starter
- 10mm bolt at rear of intake manifold
- Other wires
- Cruise control servo (8 pin connector under ABS pump)
- Disconnect alternator
- Crankshaft position sensor (rear) at EZL
- Crankshaft position sensor (front) underneath X92
- Ignition coil
- Disconnect exhaust downpipes from exhaust manifold
- Transmission
- Remove transmission mount
- Disconnect driveshaft from flex joint
- Disconnect transmission shifter linkage(s)
- Suggest removing entirely to avoid bending the rods accidentally
- Disconnect transmission slave cylinder fluid line (manuals only)
- Unbolt ground from bell housing
- Disconnect speedometer cable
- Unbolt engine mounts from chassis
- Secure engine to hoist and lift to remove. Remove with transmission attached.
M104.980 Engine Install
- Although it is possible to install the starter later, it is much easier to do it now. Bolt starter to the engine before lowering.
- Lower engine from hoist into engine bay and align motor mounts. Install without transmission.
- Connect fuel lines
- Main wiring harness
- See conversion task below
- Auxiliary wiring harness / Starter
- Set starter in place if it isn't already and reconnect wires. Bolt starter to transmission later.
- Connect oil pressure and oil level sensor wires
- Bolt wire bracket to rear of intake manifold (10mm)
- Other wires
- Connect alternator wires coming from right fender
- Connect 8 pin cruise control wires
- Connect rear crankshaft position sensor wire
- Connect front crankshaft position sensor under X11 diagnostic port
- Connect throttle cable
- Readjust idle position
- Connect power steering hoses
- Cooling System
- Connect heater return hose at back of engine
- Use W124 water reservoir overflow hose and 190E valve from thermostat cover
- Drop in radiator and connect hoses
- Vacuum system
- Use T connector at front vacuum nipple to connect to EZL and EGR/Smog pump solenoid
- Connect black striped white vacuum line from throttle body to check valve at fender behind headlight
- Connect brake booster
- Connect 3 vacuum line at rear of intake manifold
- The M104.98x introduces a new vacuum nipple. Use it however you wish or block it off.
- Fluid fill
- Power steering fluid
- Motor oil
- Coolant
- Brake fluid
- Charge AC