2.4 MFI set-up

[Fperotti]

Hi there,

I am in the middle of the rebuilding process of my 1972 2.4T MFI. Since I've read in different places, MFI for T models used to be a little bit rich at idle with all the problems regarding washed (by fuel) cylinders.

Do you know if it's true or it's a myth regarding MFI and, in case is true, what options do you suggest to solve it?.

Thank you very much in advance,

Fernando.

[YTNUKLR]

1) Get your MFI tuned right.

2) Make sure you change your oil frequently, and/or disconnect the oil breather line to the MFI pump (make sure pump has oil in it!). MFI pumps get lots of fuel in the oil.

[Fperotti]

Thanks YTNUKLR,

What I mean is, if the MFI is tuned right, will I have too fuel at idle in the engine? (Besides the fuel the pum add to the oil).

Thanks,
Fernando.

[Grady Clay]

Fernando,

It isn’t as simple as that. There are lots of different things in the MFI that can cause oil dilution with gasoline.

1) Main mixture too rich.
2) Thermostat too rich or not turning off soon enough.
3) Leaking cold start solenoid valve.
4) Overrun solenoid not functioning.
And more.

The usual and first place to look is the hot air hose to the thermostat and dirt/oil on the thermostat bi-metal discs.

The critical issue is to get the engine fully up to temperature every time you start it. Some “spirited driving” at every opportunity also helps. Hehe.

Search this forum for MFI. You will find a lot of useful information. While it is mid-summer for you, you want this fixed by fall in April. Diluting the oil with gasoline can be fatal for any engine. If in doubt, change the oil very often.

Best,
Grady

[YTNUKLR]

Grady broke it down for you very well (as always).

At idle, if it isn't tuned right, it's very possible to have lots of fuel go into the engine oil. If it is a good working system AND well-tuned, it shouldn't be bad.

I agree with Henry on disconnecting the breather line from the pump. I haven't actually done this yet but I assume you need to change the oil in the pump at approx the same time as you change the engine oil (ie., Porsche hooked the pump up to the engine because they probably figured many pumps would go unmaintained otherwise).

[Fperotti]

Thank you very much Grady and YTNUKLR,

I looked up for MFI and found a great article from Grady regarding how to break in a motor with MFI.

The last doubt I have (at least for today) is if the pump is ok and the MFI is tuned right, may I still have a mix too rich?. (A friend of mine told me that. He said he read on a BA magazine that 2.4T MFI engines always are a little bit rich at idle, even with the proper setting)

Thanks again,

Fernando.

I am not only rebuilding my engine...I hope someday everything will be in the right place again (ja, ja)