Mastering Porsche MFI Systems
Precision Fuel Delivery for Air-Cooled Icons
By Velocity Motorwerks — St. Augustine, Florida
Few things define classic Porsche performance quite like the sound and feel of a well-tuned Mechanical Fuel Injection (MFI) system. Found on iconic models like the 911E, 911S, and early Carreras, MFI represents a golden era of Porsche engineering — a time when precision mechanics and performance were in perfect harmony.
At Velocity Motorwerks in St. Augustine, FL, we specialize in diagnosing, servicing, and restoring Porsche MFI systems to their original factory performance. Our team understands that these systems require more than just technical skill — they demand experience, patience, and a deep understanding of how air-cooled engines breathe and respond.
What Makes Porsche MFI So Unique
Before electronic fuel injection became the standard, Porsche used a purely mechanical injection system designed by Bosch to deliver precise amounts of fuel based on throttle position, engine speed, and air density. Each part of the MFI system — the injection pump, throttle bodies, linkages, and cold-start enrichment circuits — must work in perfect sync to achieve that crisp throttle response Porsche drivers love.
When properly tuned, MFI systems offer instantaneous throttle response and a visceral driving experience unmatched by modern systems. But when they fall out of adjustment or experience wear, symptoms like hesitation, backfiring, poor idle, or fuel leaks can appear — and that’s where true expertise is needed.
Diagnosing and Repairing MFI Systems at Velocity Motorwerks
Our technicians at Velocity Motorwerks are trained in vintage Porsche fuel injection diagnostics, using both modern tools and period-correct equipment to ensure accuracy. We meticulously inspect and calibrate every component — from pump timing and linkage synchronization to air/fuel mixture settings — restoring the MFI system to factory specifications.
We also handle:
- MFI pump rebuilds and bench calibration
- Throttle body inspection and re-bushing
- Warm-up regulator adjustment
- Vacuum and fuel pressure testing
- Cold start and idle tuning
Whether you drive a concourse-level 911S or a vintage 911E that’s been sitting for years, our team brings your Porsche back to life with authentic performance and reliability.
Why Trust Velocity Motorwerks
Located in St. Augustine, Florida, Velocity Motorwerks is recognized for its deep expertise in air-cooled Porsche diagnostics, engine rebuilds, and fuel systems. Our passion for European engineering — and particularly for Porsche’s legacy — drives every repair we perform.
If your classic Porsche’s MFI system isn’t performing the way it should, trust the experts who understand it best. We’ll ensure your air-cooled engine delivers the crisp throttle response, reliability, and performance it was engineered for.
Contact Velocity Motorwerks today to schedule a diagnostic appointment or consultation on your Porsche’s MFI system.
