Carpokes Porsche Forum

Recently just removed the fuel rail while doing fuel lines. Went ahead and replaced the fuel injector o-rings and caps, and reinstalled everything. I noticed that there is the smallest of gaps present between the fuel injector and the engine block (equal distance on all four injectors). Pictures below: Does this look like it is seated properly? The O-rings are seated further down in the injector bores, but I can still see the yellow spacers above the o-ring. I did all this work to avoid the risk of potential fuel leaks, not create new ones . Rail is torqued down and snug on all four bolts.

Probably OK... if they are all the same.

If you suspect that they are not fully seated, spray a bit of brake cleaner at the tips of the injectors while the car is idling, if the rpms rise, then you have a vacuum leak there.

I’ve had issues reseating stock injectors. The last set of stock ones I could not get #4 injector to stop leaking. Gave up and waited to install Deka injectors for my MaxxECU. Problem solved.

If you read the boards, you will find similar stories.

To answer your question though, yes a gap can be normal from my experience. They can also rotate easily.

Also, if not seated properly they will leak. I remember not realizing one was leaking until the next morning when I smelled the fuel in my garage. So it can be a slow leak. I got lucky.

Keep a CLOSE eye on it. Be safe.

The yellow injector caps that come with most of the rebuild kits do not fit a lot of 944 injectors. If the old hats are in good shape, it's better to reuse those than to try to force the yellow ones to work. The seal is made entirely by the O-ring. I'm not quite sure what gap you're referring to in the pictures, but as long as the O-ring is pressing against the boss, it should make a good seal. If not, I would change the O-rings for a set from a known 944 supplier like Rennbay or 944online. While they are all supposed to be the same spec, I've seen at least half millimeter variation in cross section diameters among various kits. And if your O-rings are cheap and skinny, they just will not create a strong seal. I'd start by firing up the car waiting 30 seconds or so, then checking for any leaks or smell of fuel at the fuel rail. It's probably fine, but much better to be very safe, than very sorry.

Tom wrote: Sat Aug 23, 2025 11:28 am The seal is made entirely by the O-ring. I'm not quite sure what gap you're referring to in the pictures, but as long as the O-ring is pressing against the boss, it should make a good seal. If not, I would change the O-rings for a set from a known 944 supplier like Rennbay or 944online.

The gap I was referring to was the fact that I could "see" the yellow spacer and the upper portion of the O-ring forming the seal. An extra bit of info - I did order the reseal kit from Rennbay, hopefully this means it will form a solid seal. Almost ready to test and crossing my fingers.