Rover SD1 Efi Archive - (Flapper) Air Flow Meter

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With the exception of the ECU, the flapper Air Flow Meter (AFM) is the most complex and expensive original component of the Rover SD1 Efi system.

Despite a delicate mechanism they rarely fail yet do have a reputation for unreliability most likely due to abuse because a prior owner or inexperienced technician has messed with the internal workings often evidenced by observing the plastic cover has been removed and untidily replaced.

Fortunately there are still plenty of inexpensive used items available through the second hand spares market or popular auction sites.

Alternatively, given access to the correct diagnostic equipment and a degree of common sense it is possible to reset the internal components to restore normal functionality. It is also possible to adjust it empirically if one is willing to test performance between adjustments.

One might conclude that the AFM being an important, intricate and expensive (as new) part of the system, there is an argument for not messing with its internals but seeking out expert help.

Then again, experts can be rare, pricey and self-styled so why not obtain a low-cost spare S/H unit as back-up, an inexpensive CO analyser, study this article in depth and give it a go? You Decide!

The contents of this article are listed above. Read or download it in PDF format here (342kb)

Please advise of errors and omissions.

As a technical guide to Carbon Monoxide (CO) content, detection and analysis, accompanying this article is the “Gunson Gastester” Mk2 Handbook for further reading and research here (423kb)

Introduction

Operation

Testing the Functions

Initial Set-up and Testing for CO Content

Reasons for Opening the AFM

Crude Adjustment

Calibrated Adjustment

Conclusions