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!

BOSCH MECHANICAL FUEL INJECTION PUMP ASSEMBLY SECTION
BOSCH MECHANICAL FUEL INJECTION REGULATOR SECTION
THROTTLE BODY LINKAGES
THERMOSTAT DIAGRAM
FUEL SYSTEM DIAGRAM
MFI SYSTEM DIAGRAM
MFI FILTER DIAGRAM
1969 MFI SYSTEM EXPLODING DIAGRAM

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 SmileWavy

I included some suggestions for making the list easier to use. I've also included a direct link to the Check, Measure, Adjust manual. Now you have NO EXCUSE for not adding resources to this list! We MFI guys have to stick together!! :)

RPM Transducer/Speed Switch for Bosch MFI diagram. (#15 in list above). Posted here for educational purposes.

Credit for this goes to:
Early S Man
and/or
Mike Gillies of Brisbane, Australia

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Fuel Injection System Specifications (1972-1973). (#3 in the list above). Posted here for educational purposes.

http://forums.pelicanparts.com/uploa...1141339975.jpg

Replacing the MFI Fuel Filter. (#22 in the list above). Posted here for educational purposes.

http://forums.pelicanparts.com/uploa...1141344043.jpg
© Dr. Ing. h.c. F. Porsche A.G.

Bravo, David! Great posting work! Thanks!

Adjusting MFI Engine Idle (From # 2 in the list above). Posted here for educational purposes.

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© Dr. Ing. h.c. F. Porsche A.G.

Good Grief! Nice lot of info all in one place!

Thanks, maybe this time I'll keep track of it all!

Awsome thread with lots of info. Thanks for sharing!

That's the plan! Please help us out by posting any MFI information not listed above. If anyone has any links, just post them here and I'll edit them into the list at the top so that all the links are in one place. Information that would be particularly helpful is:

- Any Porsche Service School MFI publication(s) (I don't know if these exist).

- Any Factory MFI materials I missed.

- Any "How To" MFI articles from local Porsche Club publications.

- Any "How To" MFI articles from the major Porsche publications (911 and Porsche World, Excellence, Panorama, Christophorus, Total 911, GT Purely Porsche, etc).

- Copies of the "coming soon" articles not yet on our sponsor's page: (1) Bosch MFI Storage instructions , (2) Bosch MFI Pump Test Instructions, (3) Fuel System (incl. MFI) Maintenance, (4) Tuning Instructions (I would really love to see this); and (5) Mercedes MFI Adjustment Instructions.

- Helpful MFI tuning or calibration information from industry mechanics manuals.

- Additional suggestions for tools or techniques. For example, I've read that several folks have made the protractors. If you could share the technique (maybe the tool diagrams) and where you got the materials that would be helpful.

- Any links to MFI materials online in websites that are not listed above. (perhaps deep links in private sites that you'd be willing to share).

- Finally, if anyone has indexed the MFI threads from this site, posting that would be GREAT!

I'll keep posting what I have that I cannot link to and I will continue to update the top list with any links that are sent to me. Please help out this project by posting your materials and links as well.

SmileWavy

Adjusting Fuel Injection Pump with Emission Tester (From # 2 in the list above). Posted here for educational purposes.

PAGE 3.1-1/1:

Image is two posts below.

Thanks Peter! SmileWavy

looks like there is a blank space before the file name?

Located and inserted pic 4 U.
I think there is a problem with the size/format of the file name.

Adjusting+Fuel+Injection+Pump+with+Emission+Tester

http://forums.pelicanparts.com/uploa...1141726663.jpg

Lots of new links and edits added to the compilation at the top of this thread. Check it out!

Don't forget to add your resources and links -- for example, point out what MFI threads you found particularly useful -- so that we can enhance the value of this resource for everyone.

I'll make sure all new material is added to the compilation at the top of this thread so it's all in one place!

http://www.pelicanparts.com/support/smileys/yltype.gif

David - the electrical schematics for MFI equipped cars may be useful... and thanks for putting this thread together.

http://forums.pelicanparts.com/showthread.php?s=&threadid=145930&highlight=diagra m

There are three different MFI circuits:
1969 only
1970 only
’71-‘73

I’m working to convert each from wiring schematics to current flow diagrams. I have the diagrams roughed in and am collecting images of all the devices, connections and connectors. I’m using the connector nomenclature as in a ’74 current flow diagram. I’m going to identify each harness and link every wire to the harness it is in.

Does someone know of a suitable freeware wiring diagram program or can mail me a copy?

The diagrams in this series that I have are:
SL35 “Wiring Diagrams Type 911E, 911S” (1969)
NE35 “Electric Wiring Diagram Type 911T, 911E, 911S.” (1970)
SL37 “Electric wiring diagram (Part I) Type 911T, 911E, 911S, Model 71.”
SL39 “Electric wiring diagram (Part II) Type 911T, 911E, 911S, Model 71.”
0.1-2/1 “Electric wiring diagram (Part I) Type 911T, 911E, 911S, Model 72.”
0.1-2/3 “Electric wiring diagram (Part II) Type 911T, 911E, 911S, Model 72.”
0.1-2/5 “Electric wiring diagram (Part I) Type 911T, 911E, 911S, Carrera 2.7, Model 73.”
0.1-2/5 “Electric wiring diagram (Part II) Type 911T, 911E, 911S, Carrera 2.7, Model 73.”

There are two (’72) supplementary diagrams 0.1-2/9 for front and rear fog lights and 0.1-2/11 for electric windows.

There is also 0.1-2/13 “Electric wiring diagram (Part I) Type 911T with CIS, Model 73” and 0.1-2/15 “Electric wiring diagram (Part II) Type 911T with CIS, Model 73.”

’74 is the first year for Current flow diagrams.
I haven’t researched ’74 and later for MFI.
My diagrams are mostly for USA 911s.

Best,
Grady

Adjusting Micro Switch - Beginning with 1972 models (From # 2 in the list above). Posted here for educational purposes.

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© Dr. Ing. h.c. F. Porsche A.G.

Grady,

This one is simple and free

www.electronics-lab.com/downloads/schematic/006/



More comprehensive list of software options to browse

www.epanorama.net/links/software.html#schemaedit

Link containing Bentley Manual removed
 

The link to the website containing the Bentley Manual (#1 in the list at the top) has been removed to comply with board policies.

This is still a great resource. I've been adding to this list a couple of times a day. Check back often!

If you want to PM me with any links or resources you have, I'll make sure they get added to the listing at the top.

Technical Message Board Postings
 

Because of space limitations, and to give them a more prominent position, MFI Technical Message Board Postings are listed and described in this thread: MFI Message Board Index.

Fuel Injection Troubleshooting Chart
 

Fuel Injection Troubleshooting Chart (From # 1 in the list above). Posted here for educational purposes.

Page SF28:

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Page SF29:

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Page SF30:
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© Dr. Ing. h.c. F. Porsche A.G.

OK, so here's my silly question. Supposing one had a '74 Carrera. And suppose that Carrera SHOULD have had an MFI system, but because it was sent to the US, it has a CIS system. And suppose that engine was needing to be rebuilt soon...

Where would I go to find all the parts I'd need to convert it to MFI? I figure if I start collecting now, when I get to the rebuild, I'll have what I need...

It would be nice to have a checklist...

DonZ,

I’m working on that.

Best,
Grady

John Cramer's MFI/CMA mnemonic aid:

Any
Competent
Porsche
Driver
Tracks
Faster
If
Brakes
Come
Smoothly

Translates to:

Air Filter
Compression
Plugs
Dwell
Timing
Fuel pressure
Injectors
Belt (MFI pump timing)
Correlation
Smog


__________________
John Cramer

Gotta Love it! :D

Don Z

PM sent ...

1972-1973 MFI System Diagrams
 

Exploding Diagrams for 1972-1973 MFI system. (From # 10 in the list above). Posted here for educational purposes.

Porsche Spare Parts Catalogue, page GR 1-7, 2/5:
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Porsche Spare Parts Catalogue, page GR 1-7, 2/5.1:
http://forums.pelicanparts.com/uploa...1141943908.jpg
© Dr. Ing. h.c. F. Porsche A.G.

MFI 101
 

This essay was stolen from the middle of this thread:

MFI, 1972 warm-up issues (combined).

It was written by Grady Clay and deserves repeating here as a wonderful foundation for new MFI owners and as a reminder for those more experienced with MFI.


So long as you are patient and don't have 10 thumbs. you can do this. Slow is good. No one will do it as patently as you. Most don't want to pay $100/hr for an expert to go slowly. If nothing else, you gain the knowledge and experience to properly communicate with the pros (if you can find one).

...

The slippery slope you could go down is as follows: You clean the grime out of the thermostat (the device that Milt is talking about) and get it working properly. Now the engine hardly runs at all. You then think the plugs were fowled from the dirty thermostat and do a tune-up on the ignition system uncovering some "while you are there" issue. And so on with the engine not running well. All the time it turns out that the PO had adjusted the main mixture to compensate for the dirty thermostat. There are many possible scenarios but they lead to the same result -- you get lost in the system. Many professional mechanics have been bit by this also.

What to do?

Porsche developed a system for addressing MFI; it is called Check, Measure, Adjust (CMA). The emphasis is on Check and Measure before you Adjust.

The original CMA covers this sequence:
Porsche lists the Check Sequence as:
1) Air cleaner cartridge
2) Compression loss
3) Spark plugs (spark plug connectors)
4) Dwell angle
5) Ignition timing
6) Fuel pressure and flow
7) Injection nozzles
8) Injection timing
9) Correlation
10) Exhaust emission test
a) at part load
b) at idle speed

You should study the CMA document and ask questions. It is designed for the professional mechanic who is already familiar with the system. CMA was written in about '68 and assumes all the parts are new. While we have the benefit of 20-20 almost 40-year hindsight; none of the parts are new any longer. You are about to practice geriatric mechanic.

While CMA gives you most of the steps, it doesn�t tell you exactly how to do them. These few cryptic words are chapters in a 300 page book.

In fact it is so much more I call it CMA2. Following is an outline; 1 to 14. I'm going to address each one separately as an individual project. In practice there is considerable overlap. In chasing an elusive problem, you may go through the complete sequence many times.

CMA2
1) Research, read, ask, plan, and make your own personal notebook/workshop/parts manual. Collect tools and equipment or access to them. Know your starting point; check the oil sump & change the oil, go drive, measure the mileage, and take notes.

2) Air cleaner cartridge. Almost all is done with the air cleaner system in place as it will be used. Have an OE exhaust available. Make it easy to remove sump tank breather and fuel evaporative emissions hose.

3) Compression tests include both cranking compression and cylinder leak test.

4) Ignition: Spark plugs, spark plug connectors, wires, cap, rotor and general proper condition of the ignition system. Check electrical connections and grounds. Check distributor bearing, springs weights condition. Run distributor on tester. Dwell angle, points condition, condition of cam and lubricant. Ignition timing, proper advance curve, and vacuum operation. When complete and timing is set at 6000 RPM, note the timing at idle (with & without vacuum retard if applicable) and static timing.

5) Fuel pressure and flow, new fuel filter and clean the screen in the bottom of the fuel tank. Clean the tank if suspect.

6) Injection nozzles; inspect, test, clean, or replace.

7) Injection timing: If you need to adjust the MFI pump timing, use the opportunity to replace the Gilmer belt and both toothed pulleys. You can save the old ones as road spares. This is also an opportunity to replace the seals at the left cam and injection pump.

8) Camshaft timing and valve clearance. Use this opportunity to torque the cylinder head nuts and rocker arm shaft bolts.

9) Correlation and includes the condition of the throttle bodies. One of the important issues is that all the linkage moves off idle simultaneously. Check air flow at idle and just off idle for each cylinder.

10) Confirm the cold start solenoid doesn�t leak and turns on & off sharply.
Cold start thermo-time switch proper function.
'69-'71 cold start solenoid on MFI pump.

11) Over-run fuel shut-off checked for function. RPM transducer and microswitch.

12) The cold running thermostat must be clean, getting hot air, and functioning properly. When hot, it must be completely shut off.

13) Exhaust emission test; at part load, at idle speed.

14) Road testing, dyno testing and repeat entire sequence.


I'll go through the sequence one step at a time and everyone can chime in and keep it on the straight and narrow.

For now, your mission is to gather information, change oil and go drive.
Pelican and some others are full of good archival material. Do some searching and download the relevant stuff. Start yourself a "Personal Car Specific Manual"
notebook.
Your first oil change on a dry sump 911 will be an enlightening experience -- read up.
Aside from the fun, this driving has an actual purpose. You want to get everything "settled in" with highway and spirited driving. This is the only way to get good accurate compression and cylinder leak tests. You also want to carefully measure your fuel and oil consumption under controlled circumstances. Note the color inside the exhaust tip.


Don't let this seem like it can overwhelm you. Mere mortals can do this.

Automotives 101:
An engine has three basic systems; air/fuel, electrical, and mechanical. For our purposes the air/fuel system can be divided as fuel supply, high pressure mechanical fuel injection, cold start/run enrichment, and air metering. The electrical can be divided as 12VDC supply, high voltage ignition, and low voltage control circuits. The mechanical system has three basic functions; power generation, power transmission and the necessaries. Power generation has to do with the sealing of the combustion process, getting the air/fuel into the combustion chamber, and getting the combustion products out. Power transmission gets the power to where you can use it and includes the piston, rod, bearings, crankshaft, etc. The necessaries let everything happen and include valve actuation, oil system, engine cooling, etc.

The bell rang -- end of class.

Best,
Grady

Factory recommended MFI part load co2 settings
 

This came up in another thread so I thought I'd post it here:

(From # 2 in the list above). Posted here for educational purposes.

Factory recommended MFI part load co2 settings:

Note: most people find that their cars run better with 6-8%. I'm not recommending this amount, just passing on what I have read and noting my personal experience.

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http://forums.pelicanparts.com/uploa...1143402563.jpg
Copyright Dr. Ing. h.c. F. Porsche A.G.

Here's the page out of the factory manual supplement -- says the same thing. Posted here for educational purposes.
http://forums.pelicanparts.com/uploa...1143403165.jpg
Copyright Dr. Ing. h.c. F. Porsche A.G.

Tyson Schmidt posted this explanation of why MFI cars run rich at idle but get leaner when they are driven hard in this thread. I thought it concisely explained a question that many of us have about our MFI cars.

I just found this Service Circular listing the "final CO-specifications" for the 1972 911 models. Nothing new, but in the interest of getting all the information in one place ...

(From # 2 in the list above). Posted here for educational purposes.
http://forums.pelicanparts.com/uploa...1143954367.jpg
Copyright Dr. Ing. h.c. F. Porsche A.G.

Product Information Circular stating that MFI protractors are no longer required
 

(Porsche Product Information Circular P250, from # 4 in the list above). Posted here for educational purposes.

http://forums.pelicanparts.com/uploa...1144243512.jpg
Copyright Dr. Ing. h.c. F. Porsche A.G.

Deleted
 

...

OK, I stumbled on to this tread thanks to Dave’s signature link. I’ve been reading and have the tools on order but an lost on the “protractor” Pelican does not list it, is it really necessary ? Or what are we using instead of it?

Thanks for creating this tread.

Mark
Who knows he is going to have to work on his 69S MFI at some point.

The protractors are now almost impossible to find and, if you somehow manage to find all three, the directions for their use are - I'll be kind - not easy to follow unless you were trained by the factory in the late 60's. This is why Porsche came out with the 28 April 1972 Product Information Circular "P250" (two posts above) which simplifies the correlation procedures. There are a few guys that still know the old ways, Grady Clay and John Cramer for example, but from my experience if you follow CMA and P250 to the letter you'll be fine.

Adjusting the internal MFI pump partial load adjusting screws
 

Here is some fairly technical, but nevertheless valuable, stuff. These pages give some additional insight about adjusting the internal partial load adjusting screws (especially the first two pages). Note the statement "no adjustment is generally provided in the field for this operating mode on Porsche systems" on page 15. It appears that Porsche thought that these adjustments were beyond the capability of most repair shops (and certainly a backyard mechanic) so they never included this information in the Factory Service Manual or CMA. Apparently, Bosch has discussed these adjustments in their technical manuals, especially MFI Pump Test Instructions VDT-WPP 711/1B (ref Section 3.0 Inspection & Repair), but this instruction is next to impossible to find! If you have access to this document, please share!!!

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© Harold T. Glenn, Glen's Diesel and Gasoline Fuel-Injection Manual, pages 15-18 (1973). Posted here for educational purposes only.

For more information about these adjustments and other internal mysteries of the MFI pump, follow this thread.

Link to a post with MFI nomenclature, exploded drawings & service parts lists


Some interesting MFI documents

Speed Switch/RPM Transducer repair and tuning
 

How to repair and tune RPM transducers for the engine braking fuel shutoff circuit:
http://forums.pelicanparts.com/porsche-911-technical-forum/411445-mfi-gurus-friends-warren.html

Help with cold starting problem
 

Hi Everyone,
I have been battling with a cold start problem on my 1972 911 T. I am sure the answer is somewhere in all of this literature but I am having trouble finding it. The problem is that when I get in the car cold and start cranking the engine it takes probably 5 to 10 seconds before anything happens, and then it starts to sputter, pop and fizzle and shuts off a few times before it's good to go. I have sent my injectors off to supertec to have them cleaned "again" and the only other thing that I can point to is the cold start valve. Everything that I have read says that the cold start doesn't do anything until its a very low temperature though and I am in Florida. Any ideas?

Robert Karow

I've decided to try to update and make the MFI Message Board Index easier to use until the Pelican wiki is functioning. The separate posts are so that I have room to add additional links later.

The link is here.

What do you think?

MFI parts source
 

I recently delivered a very nice runnng E with an S engine to a very nice guy in Alabama. Today he called me and is having a problem. To much power at foot off the throttle. The coil sping that returns the fuel system to idle broke. The sping goes on the cross throttle shaft and one end hooks into the stack and the other around the throttle arm. Where can one find these springs? Also for all you guys with MFI, it only has to fail once and you are into the wall, full throttle with no retrun. Change that damn little spring. I noticed also that my 72 S motor has the same small hole in both stacks so would recommend the coil spring on both ends of the cross shaft. Part number and source appreciated.

For your listening pleasure, here is a funny sound from my '72 911T 2.4. It is coming from the air intake. Listen carefully to the end of the video. Some of the friendly pelican forum people think it's MFI related....

YouTube - 911t motor sound