Injectors Replaced - Now I have two fuel leaks - PeachParts Mercedes-Benz Forum

no-blue-screen · #1 07-30-2006, 10:59 PM

Well, Saturday was a busy day for me. I replaced the following items, but now I have two fuel leaks. Both of the leaks appear to be happening where the hard fuel line bolts down to the top of the injector. Curiously, the leaks are at the #1 and #5 cylinders. I did the injectors per the write-up on DieselGiant's website. The lines are connected very tightly to the top of each injector and I am afraid to tighten them more. I visited the Mercedes dealer and purchased new fuel return line as well. Two of the old injectors had a small amount of motor oil visible on the end when I removed them...would this indicate bad rings? Here is what I did....I am also suffering from serious lack of power on hills, but I am thinking this relates to the fact that I am leaking fuel.

1) Replaced both fuel filters with Bosch branded filters.

2) Installed one new copper crush washer on #5 injector delivery valve since it was leaking Diesel (this leak is now fixed). Element re-installed and torqued to 57nm.

3) Replaced all five injectors with rebuilt Bosch injectors since the originals were on there with 160k and I had some nailing. I labeled each of the hard lines when I took them off to avoid any confusion when I went to re-install them. New heat sheilds were installed with each injector and positioned properly per DieselGiants write-up. Each injector was torqued to 78nm.

4) New braided injector return line installed which was purchased from local MB dealer.

5) Installed new Hengst air filter

I was very careful to be clean about the job. The new injectors came with blue caps on each end and I left them on until the very last minute when they absolutely needed to come off. The hard fuel lines were not leaking prior to being removed. How much should I tighten the hard fuel lines where they bolt to the injectors? I tightened them pretty tight, but didn't want to be a bruiser about it in fear of breaking something.

Sorry for the long winded post, but it seems that I have fixed one leak (delivery valve) and now I have two leaks both at the injectors.

EDIT: I should also note that there is no visible smoke during the day, but at night if I look in my side mirror, I can see a grey cloud of smoke as I accellerate. She always fires right up almost instantly when I turn the key (after glowing of course). The only thing I have not done is check/clean the tank screen. I have been waiting until I can run the fuel down low enough as I don't want to drain out half a tank of Diesel.

Brian Carlton · #2 07-30-2006, 11:37 PM

Are you completely positive that you did not cross thread the nuts?

The only way to be sure of this is to start them by hand and make sure you get at least one turn before taking wrench to them.

They will not leak unless they are cross threaded or the end of the hard line is damaged.

Remove the two culprits and check the threads carefully to see if they are cross-threaded. Then check the end of the hard line for any damage or foreign material.

They need to be reasonably snug, but overtightening them is not the solution to the problem.

no-blue-screen · #3 07-30-2006, 11:51 PM

Brian, yes I am sure I didn't cross-thread them. I always start everything by hand first before I put any torque on it.

When I removed them from the car, I had them sitting on fresh newspaper, and I hit them with a shot of brake parts cleaner before I re-installed them.

I may loosen them and try again. It's always something

Brian Carlton · #4 07-30-2006, 11:57 PM

Quote:

Originally Posted by no-blue-screen

I may loosen them and try again. It's always something

Remove the line completely and take a very careful look at the end of the hard line. Look for any foreign material or any slight damage.

300SDog · #5 07-31-2006, 12:26 AM

Not unusual for hairline crack to appear next to the flared end of the tube under the nut that attaches to injectors too. The collar nut should be able to slide back to inspect the fuel line at the fitting.

no-blue-screen · #6 07-31-2006, 08:48 AM

Thanks for the ideas guys. I am going to take a look at it tonight. I will post back with what I have found.

no-blue-screen · #7 07-31-2006, 01:57 PM

Hey all,

Are there any wrenches that I could purchase that would make it easier for me to get the two lines off? I have a hard time getting to them with my standard 17mm wrench. I could just take all the lines off, but I don't want to touch the three that aren't leaking.

isaiah · #8 07-31-2006, 04:59 PM

Did you check the fuel return lines to ensure they didn't tear when you connected them to the injectors? I know the lines are new but it seems at least plausible that the fuel is leaking from them rather than the hard lines.

wheelguru · #9 07-31-2006, 05:17 PM

I have found that valve adjusting wrenches work very well for loosening the nuts for the fuel pipes. Much better than straight wrenches. You could probably accomplish the same thing with a crow-foot ratchet tool.

no-blue-screen · #10 07-31-2006, 05:17 PM

I didn't pull them back off in fear of breaking them, but would that cause fuel to get all the way up on the bolt that connects the hard line to the injector? I just assumed it was the hard line connection because the tops of the 17mm bolts on those two injectors were wet with DF. #5 seems to be leaking only a tiny bit, but #1 is leaking a bit more. I took the car on a nice 25 mile highway drive and there was a nice little puddle around the #1 injector (closest to radiator) and the DF had just began to seep down the side of the block a little. Neither are huge leaks IMO, but also IMO any leak is not a good one. Do you think it's possible that some fuel squirted out of the return lines and got all the way onto the top of that nut? Also, the new return lines didn't appear to be wet except for on the injector which I assumed was from the DF running down from the hard line nut. I will try to take pictures tonight and post them. Thing is, it doesn't leak out when the vehicle is idling...it only starts when I am driving I assume because of the increased pressure coming from the IP to the injectors. The #1 injector leaked about the equivalent to a shot glass full of DF over a 25 mile highway run..maybe a little less...it wasn't completely running down the side of the block...just starting to.

beau3198 · #11 07-31-2006, 08:44 PM

were did you get your injectors from?

no-blue-screen · #12 07-31-2006, 09:21 PM

**************

no-blue-screen · #13 08-01-2006, 12:48 PM

Well, now I am going to admit I am a total idiot! It was very hot and the heat must have been killing brain cells. #1 was not completely tighttened down. I started all of them by hand as I usually do and I get them down pretty far by hand before I put any torque on them. I must have forgotten to put the last bit of torque on #1. #5 stopped leaking after I tightened it. I also replaced the fuel return line for #3 to #2 and #2 to #1. They must have somehow split as I was installing them which made the leak worse. After I did all this, I fired er up and she was running so smooth....I thought it was a different car. I got all my power back now too since I am not loosing fuel pressure from leaks.

Thanks guys and I will take the slap in the back of the head for being an idiot and not paying attention to details.