Injector leak
 

I have an injector on the 240D which is leaking where the two halves meet. It has been in place undisturbed for about 4 years. Engine starts, runs, and idles well, just sprays fuel all over the place.

The simplest fix would be to pull it out and retighten. As I have not done this before, a couple questions come to mind:

A: What is the torque spec?

2. What is the success rate without replacing the injector?

III. After re-tightening, does it need to be pop tested for pop pressure and spray pattern?

In my notes I have the Injector Nozzle Nut to Injector body torque as 54 foot pounds.

When you pull the Injector out take a close look at the Nozzle Nut for hairline cracks. I does not happen often but some times the crack.
Another possibility is that the high pressure Fuel has eroded its way through the inside of the Injector where the parts mate; but this is extremely rare.

If it is really spraying out a lot of fuel I woud suspect a cracked Injector Nut or some other problem the just re-tightening it will not help. However, it cannot hurt to re-tighten it.
Re-tightening it will retun it to the pop pressure it was set at before it was loose.

Thanks. At first I thought it was a cracked coupling nut, so I replaced the hardline, but that wasn't it.

Did you replace the return hoses? When you did, did you happen to cut one of the barbed ends leaving a tiny grove that sprays fuel out? (Ask me how I know this is possible).

Fuel sprays out under pressure from the injector. Definitly not weeping hoses.

There is no, that I can find, torque value for the two injector parts. I had a leak between the two after I installed new nozzles. Took 'em back out, REALLY tightened them, no more leak.
However, recently I have been reading about the two parts may need help to be completely flat, use emory cloth on the two faces, but be careful.

70-80NM per FSM...but it doesn't specifically say that is for between the halves.

This is true. the picture in the FSM shows the injector in a vice clamped to the upper half, with the lower half exposed.

12. Clamp upper part (7) of injection nozzle in
vice and torque lower part (5) to 70-80 Nm.

the injection nozzle torque is 70-80 Nm when installing them.

Charlie

Be sure and replace the sealing washer if you pull the entire injector, which I would do to tighten the two halves.

You should lap the two halves using fine lapping compound, not emery cloth. The two halves need to mate perfectly to avoid a leak and if they don't you should not overtighten them to try and get them to stop. You need to re-lap them. Now, I would say, if they started leaking and never had before you could try torquing them to spec but don't just keep turning them thinking tighter will be better because it won't.

I was speaking of the bottom 1/2 of the Injector; the part I was refering to as the Nozzle Nut; the part with the 27mm hex on it as possibly being cracked.
The Injector Hard Line nuts almost never crack but what more often happens is the cone shape end gets distorted or the threads get stripped from over tightening them. Of course they cannot seal that way.

Yeppers, I will take it out to retighten.

I bought some spare heat shield washers.

Funny thing is, it was in there for 4 years without any leakage. I think it might have just vibrated itself loose.