1973 T MFI Idle Problems

Mikey D · 06-03-2003, 06:41 PM

I purchased a 1973 911T on a bit of a whim last november. My father had a 81 Targa and I loved it, and this was close. Now that I actually know a little about what I bought (should have read wayne's book first!) here's the situation.

MFI

Compression in cylinders is no worse than 120 and no better than 135.

Only oil leak is from RH lower valve cover, going to replace gaskets and put on lower turbo covers.

Rust like residue in fuel filter.

A little water in oil change. (car may have sat before I got it, and it sat all winter)

MFI NOT adjusted properly or timed right.

Low RPM power poor, over 1500 fine.

This car is a fun thing for me, but I have a hard time starting it, mind you the cold start solenoid was disconnected at the time. I was wondering if it best to just garage it for the summer and winter, rebuild the engine. OR pay to have it timed properly The rust in the fuel filter scares me a little.

Thanks to all you brilliant minds.

Mike

Wayne 962 · Wayne 962's Garage

Hmm, sounds like you need to re-read Chapter One again. Nothing you told me here says rebuild just yet...

-Wayne

Mikey D · 06-04-2003, 05:03 AM

Wayne, you are talking about your Engine Rebuilding book yes?

Mike

Tim Walsh · Tim Walsh's Garage

Use Check, measure, Adjust for us MFIWDP members it is the bible. This is off the top of my head but, you've done the first major thing, the compression check. Other early thing to check is your air filter. Check if it's dirty. If that's ok #2 is compression check (sounds ok) Next #3 is to recheck her spark plugs. Test the resistance in the wires and check for bad plugs. #4 is the dwell angle. Check that. THe rest of the list in this order are:

1. Air filter
2. Compression Check
3. Spark Plugs
4. Dwell Angle
5. Timing
6. Fuel pressure and flow
7. Injection nozzles
8. Injection timing
9. Correlation
10. Exhaust emission.

David E. Clark · 06-04-2003, 01:22 PM

Most everything you could ever want to know about MFI can be found here:

http://www.pelicanparts.com/techarticles/911_MFI/TipMFI.htm

You should also do a search on the 911 board. TONS of good stuff there as well.

Good luck!

David
'73 911E Targa

Brrrrp · 06-08-2003, 08:31 PM

Definately get the factory MFI manual and the special tools (a CO meter is handy as well, at least for idle adjustment). I have a '72T MFI. My first summer with it was very frustrating. Once I mastered the MFI, it was great. I could let it sit for 6 mos and it would instantly fire and run fine.

Good luck!
Roger