Odd part found in fuel dist. 2.7 CIS

buffarea · 07:38 PM

'75 911 2.7 cis fuel plunger part? I have been researching the web and my Bentley Bosch manual to try and locate a small 'cup' I found in my fuel inlet on the top of the fuel distributor. I thought it was a piece from thetop or tip of the plunger but now am not sure because no where can I find it in any other diagram or disassembly picture.

john walker's workshop · 09-25-2011, 08:23 PM

it's supposed to be above the plunger, and not supposed to be loose. when it gets damaged, the plunger and sensor plate can oscillate rapidly. there's a tiny hole in the top.

buffarea · 04:01 AM

Thanks for the reply! Is there any chance I can remove the plunger and reinstall it or is there no choice but to have it rebuilt? The process of removing the plunger does not scare me but I don't know if there is any advantage if it will remain loose and possibly pop out again or run poorly. How was it originally attached?

john walker's workshop · 04:13 AM

it was pressed in. if you look with a flashlight through the upper port, you can barely see the top of it when it's in position. be sure the tiny pin hole isn't distorted. you will have to figure out how to slightly expand it so it stays put, as well as what kind of installation tool it needs. then hope it stays put. you probably will need to find another unit.

buffarea · 09-26-2011, 01:07 PM

Thanks again. I will give it a go tomorrow and post the results.
Cheers!

john walker's workshop · 09-26-2011, 01:42 PM

be super careful removing and installing the plunger. don't drop it or scratch it. the tolerance is so exact that fuel does not pass between the plunger and bore, and there are no seals. likewise, do not touch the bore with whatever tool you use to try and press that piece back in.

john walker's workshop · 09-26-2011, 01:45 PM

Quote:

Originally Posted by buffarea

Thanks for the reply! Is there any chance I can remove the plunger and reinstall it or is there no choice but to have it rebuilt? The process of removing the plunger does not scare me but I don't know if there is any advantage if it will remain loose and possibly pop out again or run poorly. How was it originally attached?

you would have removed the plunger to get that piece out, right? a rebuilder would probably consider that junk, so what's to lose?

buffarea · 05:47 PM

Quote:

Originally Posted by john walker's workshop

you would have removed the plunger to get that piece out, right? a rebuilder would probably consider that junk, so what's to lose?

When I pulled off the fuel line off the fuel distributor top this piece was just laying inside there on it's side, I wasn't sure what it was but it stuck to a magnet and here it is. I have not had the plunger out yet. The end of this cup is not perfectly smooth, in fact maybe slightly hammered, and I will have to look more closely tomorrow but I don't think there is a hole in it unless it is incredibly small.
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Also, it may help to know that this car sat 7 years with no fuel in it. After repairing the fuel tank, clearing the lines and pump and a new filter this is the next step in revival. I expected to find varnish in there but not this.

buffarea · 09-28-2011, 10:06 AM

Today I was able to remove the fuel distributor and plunger to try to figure out what this little loose cup thingy is. First off there is no hole what-so-ever in this cup. It is knacker a bit and I was unable to gently insert it from the inside, and although maybe it belongs there, I'm thinking if it does it is inteneded to 'float' and not be pressed into the hole.

john walker's workshop · 09-28-2011, 10:24 AM

it does not free float and there is a hole in the center. a very small hole. how do to think control pressure gets in on top of the plunger?

buffarea · 09-28-2011, 03:43 PM

Quote:

Originally Posted by john walker's workshop

it does not free float and there is a hole in the center. a very small hole. how do to think control pressure gets in on top of the plunger?

Well obviously I need glasses! Yes of course there is a micro-hole in the end. Today I was able to securely insert it back into it's rightful location in the top of the FD body. Once there I put a hard plastic dowel in the fuel inlet to it could not go further and carefully spread the inside of the cup barrel slightly with the end of a punch. ( sorry I did not have the camera with me)
It is all back together now, freed up including smooth operation of the throttle plate.
I just ran out of time but tomorrow will reinstall the plugs and see if it will start.

buffarea · 10-10-2011, 05:26 PM

Quick update. Replaced plugs, still no start. Out of time again but frustrated and losing interest.