Eric_Oz_S2

Changed injectors today and now have a problem. After I replaced injectors the car did not run so well. I presumed it just needed a bit of tuning. When I couldn't get it to tune right I thought I'll just put the old injectors backin for now, and then realised one of the caps was missing. An inspection of the top of the piston using a borescope showed some minor maks to the top of the piston.

A compression test showed zero compression on no. 4. I just finished rebuilding the engine, and took it for its first drive today so this is really annoying.

I'll have to pull the head and hopefully it is just a bit of plastic holding a valve open. I'm really sick of working on the car at the moment.

Some say if you drop the cap down the engine will chew it up. Well I now know that is not true!

Eric_Oz_S2

I removed the intake and can see the unrecognisable remnants (it actually looked like a piece of tin foil about 5mm in width and now about a 1mm thick) of the pintle cap keeping one of the intake valves open. I pushed it into the cylinder (couldn't extract it) then filled up the closed valve with some light oil and it seems to be sealing.

Now I need to see if I can get that little bit of flat plastic out of the combustion chamber with a vac.

Tom M'Guinn

Might try some clear tubing taped/sealed to the end of a shop vac hose -- feed in through the spark plug hole and keep an eye on the tube to see if anything gets sucked up. If it's just sitting in there, you'd think you could get it by moving the tube around in there and being patient. Might also clean out the shop vac thoroughly before trying so you can check to see what actually comes out. The caps on the end of the injectors are plastic, so I wonder why you saw a tin-foil colored thing? Any chance something else got suck in there?

Eric_Oz_S2

Don't think anything else is in there. Not sure why it looked silver.

JET951

Hi Eric, If it is silver i would almost bet it is the small aluminium washers that go between the fuel rail and the inlet manifold. They were only used on the 944 S2's not the turbos. They are about 2mm thick and about 7-8mm round (when in new condition)

We have removed a few inlays from 928 S4's with the pintle caps missing, they seem to go straight through the combustion chamber without issues, at least so far the owners have been lucky.

Regards
Sean

Eric_Oz_S2

It wasn't the washers as I made sure these were accounted for. Surely the caps wouldn't cause damage to the aluminium head and peel a bit off.

JET951

No they are just to soft and get destroyed very quickly without causing damage. Something defiantly fell through the injector port while you had the fuel rail off. Do you still have all of the washers for the injector rail bolts? (the top steel washers not the aluminium ones)

Eric_Oz_S2

Yes, I have all 9 washers- 2 spacers per fixing plus the 3 top washers. They are all steel on my car. It looks like the cap gut stuck in the cylinder and bounced back into the intake valve while it closed. I really can't see what else could have got in there. It wasn't steel as it is not magnetic.

Eric_Oz_S2

Couldn't get the debris out with a vac. Started ok then engine went rough again (4 not compressing). Gave it some revs and it cleared. I suspect the bit if plastic got stuck briefly again before finally exiting the combustion chamber.

Chris White

I am a little late on this - but sticky goo on a stick is pretty handy for getting stuff out of a cylinder (if you can see it). stuff like silicone sealant works well.