MFI Werks

Expert Services for Porsche Enthusiasts.

Mark Jung
Oregon customers? Call us at (541) 272-7833

We have moved! Please call BEFORE sending any pumps in for service. We’re booked through January 2020 for full rebuilds. Check, tune & recalibrate have open appointments with a 1-2 week turnaround.

NEW Phone: 541-272-7833

Our new address is:
65440 76th Street, Bend, Oregon 97703.
Use this address for preferred FedEx or UPS shipping.

For USPS only, use:
PO Box 5903, Bend, Oregon 97708


MFI Pump Diagnosis

Pumps received for checking may only need a flow test to validate the proper flow settings and minor adjustments to the thermostat and baro cell for correct operation. Pumps received for repair are partly disassembled and cleaned, parts inspected, checked for proper operation, replace minimum parts required to optimize pumps performance, reassembled and calibrated to your pumps specifications. No cosmetic services will be performed keeping the repair cost minimal.

MFI Pump Rebuild

Pumps received for a full rebuild will be completely dissembled, all parts cleaned and inspected for ware, replace needed parts using re-manufactured or NOS as necessary, install all new seals, gaskets and bearings, replace worn cosmetic hardware with new or CAD plated hardware, reassemble and recalibrate per your pumps specification.

MFI Pump Special Modifications

Special built engines require modifications to the MFI pump. Depending on your pump type we can change your existing space cam to enhance your performance.

Fuel Injector Cleaning and Testing

We can clean and test your MFI injectors. Injectors are first tested for the proper pressure delivery then installed on are flow bench for spray patterns from idle to 8000 rpm.


The MFI Werks Story

Mark Jung has been a Porsche enthusiast since the 70’s when he traded his Marantz 250 Stereo Amplifier for a 1955 Porsche Speedster.

In 2007 during the process of restoring his award-winning 1957 Porsche 356rs Outlaw that was powered with a special built 2.7 short stroke MFI 911 engine, the troubleshooting the car’s MFI system sparked his interest in the Bosch/Porsche Mechanical Fuel Injection performance. When he couldn’t locate any qualified experts to help with the fine-tuning of his Outlaw’s MFI pump, he took it upon himself to find a solution.

After investing years of learing about the variables of MFI pump performance, Mark now consults with other Porsche entusiasts on the topic of fuel injection efficiency. He founded MFI Werks in 2008, initially offering repair and calibration services for used Porsche MFI pumps.

MFI Werks is currently operating with a selective list of MFI-related services. The company is located in Bend, Oregon, and is accepting service requests on a regular basis. In addition to providing repair and calibration services, MFI Werks is also planning to provide the following parts for sale in the future: Custom-built Space Cams, Complete Gasket Kits, and Custom “Cold Start” Mechanisms.


Shop Location

65440 76th Street
Bend,  OR  97703
Office Location

Phone and Email