Read my injectors! - PeachParts Mercedes-Benz Forum

JHZR2 · #1 06-07-2010, 11:22 PM

So I pulled my injectors, per the DIY I just posted and some questions previously. What struck me was that despite my car having been sitting for over two weeks without being run, I pulled the injectors and four of the five were very wet with fuel and there was fuel at the seat bottom where the injector touches the prechamber. Is this normal?

Hopefully using an inpact gun to carefully remove them, I didnt cause them to leak down, though if that was the case, I guess no big deal.

Anyway, some pictures:

#1 (injector furthest to the front is #1, furthest to the back is #5) came out quite wet on the sides.

And it was dirty:

Ditto for #2:

And #3:

But #4 came out very dry:

And number 5 was wet again:

Here they all are:

And the nozzle tips:

#1:

#2:

#3:

#4:

#5:

Though #4 was the dryest, it did have the most soft carbon deposits on the outer edge. It also had junk in there as soon as I pulled it out:

The rest had what looked like rusty fuel, it was murky brown, not clear yellow, as if there was rust mixed in fuel. I blotted it all out and vacuumed all the threads and seats so they were clean prior to plugging them with paper, but here are some pictures of what Im talking about:

Is this right? My indy mentioned when I started my car cold that he heard an injector "leaking". Could that actually be four of them leaking? Or was injector #4 dry because it had already leaked out prior, so it is actually the guilty one? Any thoughts?

And also to ask a real dumb question, where are the heat shields? Per my pictures, are they stuck to the injector face, or are they still in the prechamber?

Thanks!

Actros617 · #2 06-07-2010, 11:28 PM

Looks like oil to me, did someone spill some?

tangofox007 · #3 06-07-2010, 11:29 PM

Quote:

Originally Posted by JHZR2

And also to ask a real dumb question, where are the heat shields? Per my pictures, are they stuck to the injector face, or are they still in the prechamber?

They almost always remain in the prechamber.

Quote:

Originally Posted by JHZR2

My indy mentioned when I started my car cold that he heard an injector "leaking".

I would be interested in knowing what a leaking injector sounds like. And also exactly what is meant by "leaking."

JHZR2 · #4 06-07-2010, 11:31 PM

Quote:

Originally Posted by Actros617

Looks like oil to me, did someone spill some?

Might look like oil, but it was diesel fuel. I know that for certain, as I blotted it out.

JHZR2 · #5 06-07-2010, 11:32 PM

Quote:

Originally Posted by tangofox007

They almost always remain in the prechamber.

Can you point out then where it is? They all look like this:

tangofox007 · #6 06-07-2010, 11:34 PM

It's the thing with the hole in it. Hook the "hole" with a pick and the heat shield should come out.

JHZR2 · #7 06-07-2010, 11:35 PM

Quote:

Originally Posted by tangofox007

I would be interested in knowing what a leaking injector sounds like. And also exactly what is meant by "leaking."

We discussed this on here previously. I believe the difference is like two metal hammers hitting face to face, versus two hammer wooden handles tapping together.

Diesel911 · #8 06-08-2010, 01:58 AM

If you ever had and Injector Fuel Return lines that were leaking the Fuel can seep down inbetween the Threads of the Injector and Pool down there.

The other ways Fuel can get in there:
A hairline crack in the Injector Nut
Possibly Heat Shield not sealing well

On the Injector where you had soft Carbon up around the Injector Nut threads the Heat Shield must not have been sealing well.

JHZR2 · #9 06-08-2010, 09:22 AM

some of the soft lines were quite leaky. I removed and replaced them sometime back, would have thought it would have dried considering the heat and conditions up there...

Graplr · #10 06-08-2010, 10:25 AM

Quote:

Originally Posted by JHZR2

Can you point out then where it is? They all look like this:

The heat shields are basically a unique washer. So like tangofox said, they have a hole in them and are perched first thing in the chamber. 4/5 of mine were "stuck" and I had to break them loose before removal with a magnetic pick up tool. I used a needlenose pliers to break them loose.

Aquaticedge · #11 06-08-2010, 11:22 AM

to reiderate past posts-- circled red is your heat shield, it's the circle brass piece, you can lift it out with a needle nose pliers (be careful)

Diesel911 · #12 06-08-2010, 12:00 PM

The Heat Shields are made of Steel. Some Companies plate the Heat Shields so they are Brass Colored.

Diesel911 · #13 06-08-2010, 12:07 PM

Quote:

Originally Posted by JHZR2

some of the soft lines were quite leaky. I removed and replaced them sometime back, would have thought it would have dried considering the heat and conditions up there...

Yes, but there is limited ways Fuel can get into the space.

Another way would be if somtime after you replace the Injector Return Lines you loosened the Injector Hard Lines at the Injectors to bleed that Air Out. That would also allow Fuel to get into that space.

4thesporty · #14 06-08-2010, 12:53 PM

Just a quick question,

If you pulled your injectors and saw the carbon build-up. Would it be advisable to place the entire injector into an ultra-sonic cleaner.

Would this do any good to clean them, or is it better to disassemble and replace, if needed?

tangofox007 · #15 06-08-2010, 01:18 PM

Quote:

Originally Posted by 4thesporty

Just a quick question,

If you pulled your injectors and saw the carbon build-up. Would it be advisable to place the entire injector into an ultra-sonic cleaner.

The external surfaces of an injector can be cleaned with a bronze brush.