Living With A MFI Porsche

[lrodri64]

Hi!
I have a 2.4 T with the MFI and at this moment is running very rich. What i want to know is what adjustments do i have to realize in order to make it a litle bit leaner, for example i live in a country with no winter at all and i was thinking on put the thermostat on a fixed position, also i need to know the function of the solenoid that is located on the injection pump, can i disconnect?
the idle is very rough also.

Well, i am just looking at tips on how to make my MFI more daily use friendly on a country that emission testing is not an issue for a 1972 vehicle.

Please advise,
Thanks.

[boba]

A well sorted MFI car is a joy to drive. A 2.4 T would be a great choice for a driver. Not all issues with an MFI car are the injection, this link has a wealth of information and should be a big help. Once set up and running well your MFI can be rock solid.

Ultimate MFI resources thread

[Grady Clay]

[i]Irodri64p/i],

Good advice above.

First, ABSOLUTELY do not start by adjusting (or letting anyone else adjust) your MFI. If you light into adjusting, you will almost certainly end up with two or more simultaneous issues to deal with – a very difficult situation and FAR more difficult than your current problem.

First question: Did the rich running suddenly appear or did it ‘creep up’?

Are there any other running issues?

Tell us more about the rebuild, service, tuning and running history.

Be prepared to do some diagnostics only – no adjusting.
I suspect you will want to start by doing the ‘Check & Measure’ parts of CMA (Porsche’s MFI Check, Measure and Adjust procedure).

Keep in mind that CMA assumes new MFI. Our geriatric MFI has some extensions to the original CMA – I call ‘CMA2’.

The above link and the Pelican ‘Search Function’ will get you a lot of important information.

Best,
Grady

PS: Love PR. I can imagine a 911 tour and ‘canyon run’ in the mountains.

[lrodri64]

Hi Crady Clay!
I just bought the car.
There is even drops of somenthing really black in the exhaust.

[Grady Clay]

[QUOTE=lrodri64;5171991… drops of somenthing really black in the exhaust.[/QUOTE]


OK, the ‘really black’ is probably water and soot combustion products. I’ll bet the car has been moved about quite a bit while not warmed up.

First order of business is to get fresh oil in it with a new oil filter and fresh high octane fuel. Search Pelican on oil changes so you don’t end up with way too much oil or way too little. A 911 dry sump oil system is unique.


If it runs on all six, try some full throttle up-hill to 4500 rpm. Does it work OK now? Coast down and repeat. What does the tail pipe look like now? If it sounds and runs OK, increase the rpm a bit each time. Stay below 6000 rpm until you do some maintenance.

Don’t over-do this. The engine probably needs ‘break-in’ - not broken.


Tell us more about the car. Pictures are required.

Best,
Grady

[regency]

Hi, I'm sure Clay has way more experience than I. My MFI E was running too rich so I shortened the main throttle link just a bit and cured the richness problem. You should be looking for a brown colored tail pipe.

Steve

[tobluforu]

These cars like to run "rich", so your car might be ok. Follow what Grady has to say as he is the expert along with a few others on this board in regards to mfi. The mfi bible should be read a few times just to get the jist of what these systems are all about.

[DanielDudley]

When I was a kid, they used to say that 90% of all fuel problems are electrical. How are your plugs, cap, rotor, etc. ?

[RSTarga]

Why does everybody start with the MFI? This should be the last thing to adjust. If you just got the car, give it a complete initial service, oil, filter, plugs, adjust valves, timing. Do a leakdown or compression check before you start your tune up.
I don't think my pump has been checked in a couple of years, and don't adjust the linkage to cure a mixture problem or disconnect any of the electric components to the pump.