ignition miss

Almost sounds like some popping coming from one of the throttle bodies. Remove the air filter and take another listen. Also maybe a chain tensioner?

Did u ever sort the popping out? I have got the same noise coming from what seems the same cylinder (first on the right).

I had a problem in my 1970 911s engine with an MFI in trying to solve the problem of the squirters to prime before starting.In other years I saw that the squirter where located at filter housing plumbing .

I check a 1974 Carrera 2.7 RS engine and way Porsche factory did was bore 1/8" holes at the towers and connect them in series to the start solenoid on top of the fuel filter.

If others have problem this maybe the way

1974 Carrera 2.7RS

We now have Michael Burgess's new MFI book, Porsche 911 Mechanical Fuel Injection Pump, 1969-1973, in stock in the U.S., ready for shipment within 24 hours.

This do-it-yourself, step-by-step guide shows you how to rebuild and recalibrate a PED 6 KL mechanical fuel injection pump at home. The author thoroughly describes all steps in overhauling and testing pumps for the 2.0, 2.2, 2.4, and 2.7-liter engines in the 911T, 911E, and 911S. Describes the entire process, including how to build and use your own simple test rig and includes pump calibration data. Well illustrated with over 300 clear, detailed photographs of every step. Essential for 911 engine mechanics restorers. Spiralbound, 8x12 inches, 160 pages. $89.95, $4.95 US shipping; Visa/MC accepted. Call me at 303/237-0911 or visit our secure web site, Toad Hall MotorBooks, specializing in Fine Books on Mercedes Benz & Porsche since 1980; Welcome..

Frank

I am having an issue with my MFI relay. My MFI PCB has a transistor marked as D1. It is a three legged device that fell off, so I need to replace it. Diodes are 2 legged. The schematic in this thread shows T1, T2, T3 and are the small TO cans and T4 is the larger can. But a total of only 4 three legged parts. I have 5. I have 4 small TO cans that all seem to be the same part plus the larger T4. The relay PN is the same 0333.400.001. Is there a schematic error? Also where does D1 actually go on the PCB? Thanks for any help and any photos. -Rich

That transistor is what you replace with the Zener diode. Only 2 legs of the transistor are used but I guess it was cheaper for Bosch to use another transistor rather than have a different component.

see here

http://forums.pelicanparts.com/porsche-911-technical-forum/411445-mfi-gurus-friends-warren.html

So why not use the transistor to replace the transistor. Any downside to do that. It keeps it original. Comments?

The long leads are more prone to breaking due to heat and vibration making them brittle. I'm a mechanical engineer, though, so I can't give a great explanation electrically.

In the schematic it is shown as a Zener diode, so I would expect an EE would specify an appropriate Zener diode today if he saw just the schematic. I would expect that it would do a better job than a transistor. Sort of like using a swiss army knife for a task that really requires a fillet knife.

MFI Rods thread sizes
 

Lots to read in this thread. Does anyone have the R/H and L/H thread sizes for the linkage rods, need to buy tap and die