Works for 90% of all vehicles!
The Quad Digital EFIE allows much leaner settings on vehicles than other older types of EFIE's which are analog. We are now recommending Digital EFIEs for all narrow band oxygen sensors that are upstream of the catalytic converter. (Note: The Quad EFIE uses a pair of analog EFIEs for the downstream sensors)
Digital EFIEs have the following benefits: Can make the air/fuel mix much leaner than earlier designs. With this device you can lug down your engine, and often kill it if you set it too lean. Absolutely rock steady adjustment no matter what temperature the environment.
Will work with older, "tired" oxygen sensors that should have been replaced. One adjustment pot modifies both upstream (Digital) EFIEs equally, and similarly, one pot adjusts both downstream (Analog) EFIEs. This makes these devices easier to set.