Fuel Injector Leaking Air
 

My fuel injectors all 8 are leaking air causing a horrible rough idle. I confirmed this using a smoke machine, and putting droplets of water too see it get sucked in. They are brand new injectors, just installed brand new gaskets still leaking. Tried soaking them in motor-oil too swell them up, still leaking!! Torqued to specifications, tried over-torque-ing them but still leaking.

I've done pretty much everything so far to the jag to keep it in nice running condition but this problem makes me not even want to drive the car. This is the only mechanical problem with the car right now!

Should I try putting RTV or something on them? The only other thing I can think of is when I installed new heater hoses when putting everything back together, maybe I didn't align something properly? where it makes the fuel rail not seat correctly? I did put all the bolts back where they belonged but this is the only other thing I can think of??? I am desperate for help if anyone has advice please let me know thanks!!

*they are leaking where the fuel injector mates with the intake manifold, I can find a picture if needed

Hi stran0020,

It can take quite a bit of force to fully seat the injectors in the manifold, and since the screw brackets on the fuel rails are formed of thin metal, you can't rely on torquing the screws to actually force the fuel rail down and seat the injectors...the brackets can just deflect or bend. My guess is that you need to apply more pressure on the rail above each injector to be sure they really are fully seated. Loosen the bracket screws first to give yourself some "wiggle room" to help push the injectors into position.

I don't know if this works on an X308, but on some vehicles it is easiest to install the injectors in the manifold first, then align the fuel rail ports with the tops of the injectors and press it home.

Also, in general it is not wise to use RTV around injectors because its fumes can damage O2 sensors (some sealants are formulated to be "sensor safe," trust at your own risk).

Cheers,

Don

The manual also specifies that the o-rings be lubed with petroleum jelly, aka vaseline during install. This is to prevent nicks. So be sure to check the existing ones for nicks.

Otherwise, as noted by Don B., fully seat before starting bolts.

I do tap it down with a mallet but should i try more force?

Also it is not leaking any fuel whats so ever, just air. Would it still be possible its not seated? I just don't understand :( I'll try again today hopefully

Are you certain the leaks are at the injectors or could they be at the manifold gasket?

yea im pretty positive it's leaking at the injectors because I'm using a smoke machine

Anyone have a idea on how to solve this? :(

Ran across the same issue while reading other car forums (BMW, etc)

The consensus on those articles seems to be:
-Make sure all of the O-Rings are replaced with OE equipment and are the proper match. Some people have received incorrectly sized or varying sizes of seals.
-Make sure the mating surfaces are clean, free of any dirt/debris and nick free.
-Ensure the new O-rings are properly seated on the injector, and apply the petroleum jelly so they can be properly seated
-Seat the injector fully first (can use a rubber mallet) before bolting down with the bracket
-The new O-Rings could have been 'rolled' or pinched during their install, which would allow some air to bypass the rings. Some mentioned the rings broke during install and it wasn't apparent until the injectors were removed again.

Hope you can resolve this issue -- This is helpful info for any of us who have to R/R the injectors in the future.