The following article shows how to diagnose and perform a rough idle repair on a BMW E60 5 series vehicle with the M54 six cylinder engine. These “work horse” engines were used in many other BMWs besides the early E60 5 series models, including the 3,7,X and Z series cars and SUVs. The following repair can be used on any of these other vehicles with minor modifications.
A BMW E60 rough idle repair is an easy procedure that is usually caused by a bad DISA or idle control valve on the intake manifold of the car.
As the first wave of BMW 5-series E60s reaches an automotive geriatric age of 15 years old, parts begin to wear out and our beloved bimmers start to lose their once silky sweet engine performance. One of the most frequent performance issues plaguing the older six cylinder BMW M54 engines is a rough or fluctuating idle. Does the engine rpm in your car repeatedly drop and then recover when idling at a stop? Are you noticing fluctuations in your rpms when holding the accelerator at a constant speed? Is your car idling rough or experiencing a loss of power when you depress the accelerator pedal? If you are experiencing any of these rough idle issues, there are a couple of quick rough idle repairs that can get your bimmer performing like new again.
There are two parts that are common contributing factors to a rough idling M54 engine: the DISA valve (also known as the intake air adjustment valve), and the idle control valve.
The DISA valve is located on the top left side of the intake manifold. It’s function is to “fine tune” the flow of air through the intake manifold. This intake tuning is done with the use of a flap, which redirects air within the intake manifold in order to achieve optimal flow into the cylinders. Common signs of a failing DISA valve or DISA valve o-ring are a rough idle and poor fuel economy.
The idle control valve on the BMW six cylinder engine is also located on the left side of the intake manifold, just below the DISA valve. It’s function is to bypass air around the throttle body so the engine can get air when idling. It also supplies air to the engine when you take your foot off of the accelerator at higher RPMs. Common signs of a failing idle control valve are fluctuations in the idle speed, and near stalling conditions when the foot is abruptly removed from the accelerator at a higher RPM.
The BMW Repair Guide recommends replacing both valves when performing a BMW E60 rough idle repair. Since both parts have a maximum life span of approximately 100,000 miles, if one is failing most likely the other is ready to go as well. Do yourself a favor and spend the extra money and replace both parts.
1. DISA valve (required) – The entire DISA valve should be replaced, even if it is just its gasket that is leaking. A failed DISA valve can actually come apart, ejecting plastic parts into the cylinder head and destroying an engine.
2. Idle control valve (required) – The following kit includes valve, grommet and rubber mount.
3. Intake boot (optional) – Is your intake boot getting old and brittle? A cracked intake boot allows unmetered air into your car’s intake system, causing a rough idle, fault codes and triggers the service engine light on your dashboard. Now is a great time to replace your intake boot while you have it removed for this repair.
4. Air Filter (Optional) – When is the last time you replaced your car’s air filter? The air filter must clean 8000-9000 gallons of air for each gallon of gasoline burned inside the engine, without restricting the air intake. A clogged air filter is also a cause of a rough idle. Replace yours now while doing this repair!
- Remove the two 13mm bolts anchoring the air box assembly to the left fender. Using a flat blade screwdriver, loosen the pipe clamp securing the intake boot to the air box. Remove the electrical connector from the mass air flow (MAF) sensor. Carefully lift upwards on the air box assembly and remove from vehicle.
- Disconnect the electrical connector from the DISA valve. Remove the two T40 torx screws anchoring the DISA valve to the intake manifold.
- Grasp the DISA valve and pull straight out from intake manifold and remove from vehicle.
- Loosen the hose clamp and disconnect the intake boot from the idle control valve.
- Carefully grasp idle control valve and pull straight out from intake manifold. Disconnect electrical connector from idle control valve then remove valve from vehicle.
- Using a pair of needle nose pliers, carefully remove idle control valve grommet from intake manifold.
Follow the above steps in reverse for reassembly with the new parts. Note that the new grommet is notched – match the notch up with the tab in the intake manifold to ensure correct positioning during reassembly. We suggest coating the inside of the grommet with a little dilithium grease to help with insertion of the idle control valve. Make sure all of your hoses fit tight and hose clamps are securely fastened.