Cylinder Deactivation System (MDS) in Hemi engines, while designed for fuel efficiency, can sometimes lead to issues. If you’re looking to disable MDS on your Hemi engine, particularly using OBD2 solutions, here’s a breakdown of your options.
Option 1: Range Technology MDS Manager OBD II Device
One popular method to disable MDS is by using an OBD2 device like the MDS Manager from Range Technology. This device plugs directly into your OBD II port and effectively turns off MDS without requiring permanent modifications or ECU tuning.
Range Technology is a well-known company specializing in these types of devices, starting with GM vehicles and expanding to FCA (now Stellantis) products. Their MDS Manager for 5.7L Hemi V8 engines is available for around $200.
https://www.rangetechnology.com/products/mds_manager/
Important Considerations for OBD2 Devices:
- Vehicle Compatibility: While generally effective for Hemi 5.7L V8s, it’s crucial to verify compatibility with your specific vehicle model, especially if you own a Jeep Grand Cherokee as it’s not explicitly listed on their site. Contact Range Technology directly to confirm compatibility.
- Authenticity: Purchase directly from Range Technology or authorized dealers to ensure you receive a genuine device with the latest firmware and avoid potential scams or clone products.
Option 2: Software Tuning by a Performance Shop
If an OBD2 device isn’t suitable or you prefer a software-based solution, you can have a reputable performance shop tune out MDS. This involves reprogramming your ECU to disable cylinder deactivation.
Key Points for Software Tuning:
- Find Experienced Tuners: Research and choose a performance shop with proven experience in tuning Hemis and disabling MDS.
- Cost: Software tuning is generally more expensive than OBD2 devices but offers a permanent software-level disable.
Option 3: Hardware Replacement (MDS Delete)
For a more comprehensive solution, albeit the most expensive, consider a hardware MDS delete. This involves replacing the MDS-specific components like camshafts and lifters with non-MDS versions. This option, combined with ECU re-tuning, physically eliminates the MDS system.
Considerations for Hardware MDS Delete:
- Highest Cost: This is the priciest option, potentially costing $3,000 or more, including parts and labor.
- Expert Installation Required: Hardware replacement demands a highly skilled and experienced shop specializing in MDS deletes.
- Hardware Solution: While Options 1 and 2 disable MDS via software, the underlying MDS hardware remains. Hardware deletion removes the system entirely, mitigating any potential future hardware-related issues associated with MDS components.
Conclusion
Disabling Hemi MDS can be achieved through several methods, ranging from simple OBD2 device plug-ins to more involved hardware replacements. For a straightforward and relatively inexpensive solution, the Range Technology MDS Manager OBD2 device is a good starting point. If you’re seeking a software-based disable, professional tuning is a viable option. For a complete and permanent removal of the MDS system, hardware replacement is the most thorough but also the most costly route. Always prioritize reputable shops and verified product sources when addressing MDS deactivation.
