Installing New Injectors

Kevin Taylor · Kevin Taylor's Garage

What is the procedure? Can any one walk a first timer through it? Do the lines need to be undone from the MFI pump too?
Anything else I will Need To Know.

Thanks In Advance K.T.
1973 911E MFI 2.4
1965 DEVIN

mr.bch · 08-08-2003, 04:45 PM

I just did it (in my SC) while trying to trouble shoot another problem (won't come off idle withour dying).

Read the Pelican Tech Article.

http://www.pelicanparts.com/techarticles/bob_tindel/911_inj_nozzle.htm

The article helps. It is not that hard. I replaced the plugs after I pulled the injectors and the injector job went quicker. I cleaned mine and replaced the seals.

Early_S_Man · 08-08-2003, 05:14 PM

Kevin,

Actually ... please disregard any reference to changing CIS injectors, since they aren't threaded into the cylinder head, and don't have formed steel lines [similar to hard brake lines] with compression nuts at both ends!!!

The job requires a set of metric flare-nut wrenches. New copper sealing rings are needed, too. The lines DO have to be loosened from the injection pump before they can be removed from the injector. A back-up open-end wrench MUST BE USED in conjunction with the flare-nut wrench to loosen the compression nuts at both injection pump and injector!!!

Take your time ... and be prepared for the compression nuts to break loose rather suddenly ... a padded/insulated glove on the hand operating the flare-nut wrench may be able to save significant amount of hide from being torn off the back of your hand when rapid contact is made with other engine pieces in close proximity!

mr.bch · 08-08-2003, 05:27 PM

Oh, sorry. I blew through the post too fast... missed the MFI part.

But, actually, my SC DOES have hard steel lines with compression nuts at both ends.

Size 12 and 14mm flare nuts wrenches did it for me. But I'll shut up and let the MFI guys walk you through it.

Kevin Taylor · Kevin Taylor's Garage

Thanks for the information. Couple more questions.
Can I pick up a set of the wrenches at local auto parts store,
sears or are they special tools? Copper Sealing rings?
They sent me rubber ones. Can I use them or get the copper ones?
Am I going to see a lot of fuel dripping on this project.
Don't want any fires.

Thanks Again K.T.

Rot 911 · 08-11-2003, 10:07 AM

Sears sells metric flare wrenches
You need the copper sealing rings, the rubber ones are incorrect for the MFI
You only have some minor fuel drips. The MFI injectors require over 200lbs psi to open. However, once you loosen up the injector from the line whatever fuel is in the line will run out.

Additional tips: When I removed the MFI lines and injectors from my '72E I had no problem at the pump end. However on the injector end one injector would not come off the line no matter how much PB Blaster, heat, tapping I did. If you see the line start to twist, STOP!