Disable MFI Cold Start?

OkieRon · 01-09-2004, 08:39 AM

I am replacing the "sat for 14 years" fuel lines. A local wrench told me that in the 70's Porshce directed owners to disable the cold start fuel pump and lines on MFI due to possible fire hazard. Is this correct or possible and how do I do it?

Thanks
Ron

Rot 911 · 01-09-2004, 09:59 AM

Ron he may have been referring to the early MFI cold start which had the cold start injector shooting gas into the air filter housing and yes that damn thing could catch on fire. The later cold start lines run into the base of the throttle bodies and there is no problem with these. Easy to tell which one you have just by looking.

OkieRon · 01-09-2004, 10:11 AM

Thanks Kurt,
I have a 72T. The MFI has the lines running along the side with "T"'s going into the side of the MFI housing. Would this be the later or earlier style (considering its a 72' I would guess the latter)

Thanks Ron

304065 · 01-09-2004, 11:40 AM

Later style. I disabled the old school "pisser" in the airbox, that's a fire waiting to happen. One of these days I'll fab up a squirter in the stack like the plastick stack type.

Bobboloo · Bobboloo's Garage

As John said you have the later style, no problem. Just make sure the the hoses going to the stacks aren't cracked and dried out.

OkieRon · 01-09-2004, 04:17 PM

Unfortunately they are cracked and dried out. Worst of all, several of the plastic "T"'s are missing. Any thoughts on a replacement as I heard they are nearly impossible to find?
Thanks Ron

HawgRyder · HawgRyder's Garage

My 69S doesn't have the squirters...it does have the solenoid on top of the filter assy...but no lines coming off and no wires.
What I do have is the enrichment solenoid on the MFI pump.
I have this hooked up to a separate switch so that I have control of the amount of fuel being enrichened on start.
Seems to work even in the extreme cold (0 deg C) and only needs to shoot extra fuel for about 5 - 10 seconds.
Bob

OkieRon · 01-09-2004, 04:28 PM

More to the point. . . Is it possible to disengage the LATER STYLE cold start apparatus on the MFI. Can it be run without the cold start lines (as it would be with the earlier style disengaged) or is it necessary or prudent to use it. If not, how do you disengage the cold start pump so that gas isn't spewing all over the MFI. Thanks Ron

pwd72s · 01-09-2004, 04:46 PM

Quote:

Originally posted by OkieRon
Unfortunately they are cracked and dried out. Worst of all, several of the plastic "T"'s are missing. Any thoughts on a replacement as I heard they are nearly impossible to find?
Thanks Ron

I've never done this personally, and it would not be "original"...but I've often wondered if the metal T's made out of chrome plated brass as sold in aquarium shops as air line T's would work. The diameter is close...

jim72911t · 01-09-2004, 05:33 PM

Quote:

I've never done this personally, and it would not be "original"...but I've often wondered if the metal T's made out of chrome plated brass as sold in aquarium shops as air line T's would work. The diameter is close...

If I'm not mistaken, the "T" fittings have an oriface that distributes a spray pattern, rather than just dumping fuel into the TB's.

I was able to find a couple of replacements at a P-car salvage yard a few years ago; I think it was Best Deal or EASY, but I can't be certain.

Oh yeah, WHY did i need replacements?

Quote:

Just make sure the the hoses going to the stacks aren't cracked and dried out

What he said. It's also a good idea to make sure your spark plug wires aren't so old that they're arcing inside the engine compartment.

This happened during the first week of 911 ownership for me. I hope I'm a bit wiser now.

Jim

Bobboloo · Bobboloo's Garage

To unhook the cold start on a 2.4 all you do is unplug the wire from the top of the fuel regulator (console that mounts to the chassis) that the filter screws on to.

Quote:

Worst of all, several of the plastic "T"'s are missing. Any thoughts on a replacement as I heard they are nearly impossible to find?

Nearly impossible unless you hang out here.
How many do you need?

OkieRon · 01-09-2004, 08:56 PM

I need two.

Bobboloo · Bobboloo's Garage

Email me your address at ginsburg@lanset.com and I'll drop you two in the mail.

sithot · 01-09-2004, 10:17 PM

Quote:

Originally posted by OkieRon
I am replacing the "sat for 14 years" fuel lines. A local wrench told me that in the 70's Porshce directed owners to disable the cold start fuel pump and lines on MFI due to possible fire hazard. Is this correct or possible and how do I do it?

Thanks
Ron

Correct quote. Porsche DID direct owners to do this.

Tom