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David E. Clark David E. Clark is offline
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Join Date: May 2003
Location: Summerfield, NC
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Lightbulb Ultimate MFI resources thread

The idea came up in another post to gather all the MFI related resource information (with links) in one post. The Bosch Mechanical Fuel Injection Compilation by John Hunt is a GREAT start but lets try to get it all in one place!

I'll start with everything in my collection with links included where I have them. I have also included identifying information for other stuff that I have collected (without links). Lets get all the information in this post. It will make a great resource. Here's my stuff:

1. Factory Workshop Manual, Volume I, pages SF 11 through SF 42. These pages give a description of the system along with useful schematic diagrams. Of particular help is the three page "Fuel Injection Trouble Shooting Chart." Buy the Factory Workshop Manual here. Expensive but worth it!

Fuel Injection Troubleshooting Chart pages SF28-SF30. Posted in this thread below.

2. Factory Workshop Manual, 1972 Supplement, volume 2, pages 1-1/1 through 1-2/3; 3.1 1/1 through 1/4. Contains useful information about adjusting the injection pump with an emission tester and adjusting the micro switch on the 1972 and 1973 models. Buy the Factory Workshop Manual Supplement here. Expensive but worth it!

Adjusting Fuel Injection Pump with Emission Tester, page 3.1 1/1. Posted in this thread below.
Adjusting MFI Engine Idle, pages 3.1 1/2 - 3.1 1/3. Posted in this thread below.
Adjusting MFI Micro Switch - Beginning with 1972 Models, page 3.1 1/4. Posted in this thread below.
Factory recommended part load co2 settings. Posted in this thread below.
Explanation of why MFI cars run rich at idle but get leaner when they are driven hard. Posted in this thread below.

3. Porsche Technical Specifications - 72, 73 Models Fuel Injection System pages 54-55. Posted in this thread below. Buy the Factory Specifications Books here.

4. Mechanical Fuel Injection, Check Measure Adjust. The Bible! 47 pages of must have material for any MFI owner.

Differences in Check, Measure Adjust Manuals.

Porsche Product Information Circular P250 stating that the MFI protractors described in the factory workshop manual and CMA are no longer required to set proper correlation. Posted in this thread below.

5. Bosch MFI Repair Instructions. Just follow the link from the homepage to this article. Detailed repair instructions including useful torque specs.

6. Bosch MFI Repair Instructions, supplement 2. Just follow the link from the homepage to this article.

7. Fuel Injector Maintenance. How to maintain mechanical fuel injectors -- Just like it sounds!

8. Mechanical Fuel Injection by Leslie Rice. Wonderful overview of the MFI system from a guy that really understands it. Great advice like "NEVER DEVIATE" from the sequence outlined in Check, Measure and Adjust.

9. Adjustments to the MFI pump for timing and mixture by Leslie Rice. Includes advice on making adjustments to the MFI pump, timing the MFI pump and inspecting the MFI timing belt. Also describes useful tools.

10. MFI diagrams and cutaways. Great illustrations including exploding diagrams in case you ever take the thing apart!



EXPLODING DIAGRAMS FOR 1972-1973 MFI SYSTEM. Posted in this thread below.

ELECTRICAL WIRING DIAGRAM FOR EARLY MFI CARS. These electrical wiring diagrams were converted by Derek Murray. Electrical diagrams for the early cars are also posted on the Rennlist website here.

11. Group 21 Fuel Injection System exploding diagrams from Parts Manual. Choose "Porsche Original PDF Parts catalogue" from the left hand column and your year and model from the right column. More valuable exploding diagrams.

12. Excellence Magazine technical notes II, pages 60-66.

13. RPM Transducer/Speed Switch for Bosch MFI diagram. Posted in this thread below.

14. Throttle body linkages diagram from "Porsche Service Repair Handbook" Clymer Publications (1976) page 210. This same diagram is on page SF22 of the Factory Workshop Manual (April 1972 edition).

15. Autosolve Mechanical Fuel Injection article. Really deals with the Bosch K-Jetronic system but still a pretty good read.

16. Project 30, page 91, Mechanical Fuel Injection Troubleshooting and Adjustment, 101 Projects for your Porsche 911 . Buy the book here.

17. American Bosch Fuel Injections, Equipment and Service (74 pages) (1972). Covers MFI for Diesel engines but has good background information.

18. Replacing the MFI Fuel Filter from Porsche 911T/E/S Model '73 Driver's Manual page 62. Posted in this thread below. Buy the Driver's Manual here.

19. Porsche Panorama Magazine has a decent overview article called "Porsche Mechanical Fuel Injection Systems" in the April 1999 issue at page 30.

20. "Up-Fixin der Porsche" has various somewhat helpful bits on Mechanical Fuel Injection at:

"Mechanical Fuel Injection" in Volume 5, page 146. Compares MFI to CIS and carburetors.
"Mechanical Injection" in Volume 6, page 31. Short discussion of gas in oil problem with some MFI systems.
"Mechanical Injection Pump Rebuilds" in Volume 7, page 120. Idle adjustment on MFI cars.
"Mechanical Injection Pump Rebuilds" in Volume 7, page 121. Rebuilders addresses current as on July 1986. More recent information about MFI rebuilders can be found here.
"Mechanical Injection" in Volume 8, page 125.
"Mechanical Injection 911T" in Volume 8, page 125.

The "Haynes", "Clymer", "InterEurope", "Chiltons", and "Autobooks", manuals only have VERY general information about Mechanical Fuel Injection. I also have a "Drake" Porsche 911 Workshop Manual but it really covers the 356 (go figure), so it's no help.

21. Of course, the search function on Pelican Parts is your best friend!

Because of space limitations, MFI Technical Message Board Postings are listed and described in this thread:

MFI Message Board Index

Please add your links and resources to this page and make it a better resource for all of us
Please help the MFI community keep the Ultimate MFI resources thread and the Mechanical fuel injection resource index up to date. Send me a PM and I'll add your materials and suggestions.

1973 911E Targa (MFI)

Last edited by David E. Clark; 04-05-2006 at 05:36 AM..
Old 03-01-2006, 01:39 PM
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