Why don't DRI injectors run lean over time like conventional injectors?

Baked-on fuel deposits that coat the tip of the injector do not reduce the metering area of the small holes, so the injectors maintain proper fuel metering regardless of fuel quality.

What components are shown in the DRI injector diagram?

The needle, the director/metering plate (single/multi-hole), and the Deposit Resistant Injector (DRI) metering assembly, in figure V8012-1A.

Home/ Registry/ Ford/ Bronco/ 1987-1991/ “Eddie Bauer”/ Photo supermotors.net/registry/media/900171

Ford 5.8L EFI Deposit Resistant Injector (DRI) Diagram & Description - E4OD

Service manual page on deposit resistant injectors with cutaway figures

‹ ›

Manual page describing deposit resistant injectors for 5.8L EFI engines with cutaway figures of the metering plate and needle.

AI caption December 2011 · Photo 993 of 1799

This scanned manual page describes the Deposit Resistant Injector (DRI) fitted to some vehicles equipped with 5.8L EFI engines and the E4OD transmission. The text explains that the DRI was designed to eliminate the lean fuel delivery problems that occur with conventional multi-port fuel injectors when low grade, non-detergent fuels are used. Unlike a conventional injector, the DRI has no pintle on the tip of the needle; instead, it meters fuel through four small holes in a metering plate on the end of the injector. Because baked-on fuel deposits that coat the injector tip over time do not reduce the metering area of these small holes, the injectors maintain proper fuel metering characteristics regardless of fuel quality and do not deteriorate lean as conventional injectors do. The page includes a cutaway line drawing of the injector with callouts identifying the needle, the director/metering plate (single/multi-hole shown in a magnified circle), and the DRI metering assembly (also magnified). The illustration carries the figure reference V8012-1A. A reader learns how to identify a DRI injector, why Ford used this design, and how its metering plate design differs functionally from pintle-type injectors.

Is this accurate? Sign in to help verify it.

Frequently asked questions

What is a Deposit Resistant Injector (DRI)?: A fuel injector installed on some vehicles with 5.8L EFI engines and E4OD transmissions, designed to eliminate the lean fuel delivery problems that occur with conventional multi-port injectors when low grade, non-detergent fuels are used.
How does the DRI injector meter fuel differently from a conventional injector?: It has no pintle on the tip of the needle; instead, it meters fuel through four small holes in a metering plate on the end of the injector.
Why don't DRI injectors run lean over time like conventional injectors?: Baked-on fuel deposits that coat the tip of the injector do not reduce the metering area of the small holes, so the injectors maintain proper fuel metering regardless of fuel quality.
What components are shown in the DRI injector diagram?: The needle, the director/metering plate (single/multi-hole), and the Deposit Resistant Injector (DRI) metering assembly, in figure V8012-1A.