ORM is short for OFF ROAD MODIFICATION. The orm consists of unplugging the Mass Air Flow (MAF) sensor. The MAF is between the turbo and the air box. By disconnecting you disable the EGR. By turning off the EGR you improve your fuel milage and power greatly. Also you set off the check engine light (CEL) by disconnecting the MAF. It is called the ORM because it is not necessarily a legal modification unless you are driving offroad.

As you're looking at the connector, pull the red clip back towards you (slides towards the wires). You should be able to do it w/ just your fingernail, but a coin or something similar may help. Once the red tab is extended, mash down on the tap and the connector just pulls/slides off.

The ORM increases the MPG's, smooths out the engine and make it more responsive while reducing all the soot you would deposit on the trees. IF ONLY USING OFF ROAD the oil will clear up and not be soot black after a couple of oil changes.

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91 MB 300D 2.5L Turbo. Her's

05 MB E320 CDI. Mine

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91 MB 300D 2.5L Turbo. Her's

05 MB E320 CDI. Mine

This is actual picture of EGR Valve that has been removed.

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91 MB 300D 2.5L Turbo. Her's

05 MB E320 CDI. Mine

What you will need: Flat head screwdriver, zip tie, rag(s), also hose clamps would be helpful but not necessary.

Changing the fuel filter is not hard at all and can be easily done in 1 hour or less the first time.

1. Disconnect the plugs and hoses circled on the picture

2. You can zip tie the two hoses off to the side so they wouldn’t be in my way when removing the filter or let them hang loose.

3. Disconnect the water sensor on the bottom of the fuel filter.

4. Twist the fuel filter in order to remove it. Righty tighty, lefty loosey.

5. Unscrew the drain valve from the filter that connects to the water sensor plug and screw it on to the new filter. Be careful not to break the thing.

6. Lubricate the rubber grommet of the filter before you install it. You can use a little vaseline.

7. Install the filter and tighten approx 1/4 to 1/2 turn then connect all hoses and plugs.

8. Now use the manual pump that’s on top of the fuel filter assembly to get the air out of the system. Pump a couple of times and then open the bleeding screw for a short amount of time. Do this until there is a steady stream of fuel with no indication of air bubbles. I would recommend towels or drain hose to prevent fuel from being pumped onto top of engine.

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91 MB 300D 2.5L Turbo. Her's

05 MB E320 CDI. Mine