e300 w124 new injectors now "nailing" - PeachParts Mercedes-Benz Forum

barney55 · #1 12-20-2007, 06:31 PM

Just replaced the injectors on 180k mile 95 e300 diesel non turbo. It was quiet before but with some cold running issues. The cold running issues are still there, once warm the engine pulls better than it did with the old injectors but it is noisier at idle with what I think is called nailing - loud clanging that I can also feel pulsing through the metal fuel pipe from the IP to the injector.
What is causing this and is it possible to get rid of it?

tankowner · #2 12-21-2007, 12:42 AM

Hmmm. Good question. I also have a '95 E300D and have been experiencing what I believe to be injector nailing from time to time on cold start ups. My plan is to eventually replace the injectors as the engine has 180k miles on it and I have no record that they have ever been changed. I'm not sure what would be causing this in your car if you just replaced the injectors. Did you replace just the nozzles or the whole injector? What brand did you use? Where were they manufactured, etc.?

Sorry I can't help out more. Maybe give a little more info and see if others have any additional feedback.

TMAllison · #3 12-21-2007, 01:12 AM

If you replaced nozzles only (most common) were the pop pressures adjusted to bring them to factory specs?

barney55 · #4 12-21-2007, 05:17 AM

Hi
They were complete replacements using Bosch - they are available here at about $70 exchange from a Bosch dealer; they are about 3 times that from MB. You have got me thinking about the pop pressures. I assume that these injectors are used in multiple different cars with different pressures? Is that the difference with MB supplied parts maybe?
How easy is it to adjust them?

barney55 · #5 12-21-2007, 05:18 AM

By the way mine is doing it cold and hot.

Number_Cruncher · #6 12-21-2007, 06:37 AM

If the injectors you fitted were from Bosch, and the part numbers were for your car, the pop pressures will be fine. Actually, the injectors are insensitive to small changes in pop pressure anyway - it's really not something to get excited about.

Large changes in pop pressure usually indicate a problem with the injector that needs to be fixed before you reset the pop pressure, but I'm sure you aren't in this regime when you've fitted replacement Bosch injectors.

Which injectors are making the noise?

barney55 · #7 12-21-2007, 08:05 AM

It is whichever injector is served by the line that is the very front most one from the IP. I can feel that line pulsing. Maybe some others as well. The noise goes away just above idle.

JeremyPDX · #8 12-21-2007, 01:12 PM

I have a 95 E300 with 193K and just cleaned the in-tank fuel screen. The records from the previous owner show that it had never been done. My car used to "nail" when it was cold but I had gotten used to it. There was so much black slime on the screen that I couldn't see through it! After cleaning the screen, my engine is so much quieter and it never nails when cold! Not only that, but it seems like I gained 40 more HP! Just a thought, but if you don't know the condition of the screen, it could be starving your engine of fuel which can lead to "nailing".

Good Luck!

barney55 · #9 12-21-2007, 07:10 PM

Thanks - I have had this car for 9 years and 150k of the miles - and this has never been done - where is this located and is it easy to do?

Parrot of Doom · #10 12-21-2007, 07:13 PM

Next to the primary fuel filter.

barney55 · #11 12-21-2007, 07:16 PM

He is talking about an "in tank screen" - I assume this is in the fuel tank?
I already replaced the main and secondary filters in the engine bay.

BoomInTheTrunk · #12 12-21-2007, 07:54 PM

its under the car at the bottom of the fuel tank. The fuel line is connected to it. Try to change it when you have little fuel in the tank as you dont want to have alot of fuel comming out. Its a very large size so you might need to get a bigger socket than you have. Just follow the line and where it goes into the tank that is where it is.

JeremyPDX · #13 12-21-2007, 07:57 PM

The in-tank screen is in the bottom of the fuel tank. The fuel feed line is threaded into the screen and can be located by following the fuel line that is located just above the diff (under the car). Drive the car as far as you can without running it empty and then pull the rubber lines from the hard lines (return and feed) on the chassis to drain the rest. It is a mess, but a 5 gallon bucket catches most of it. Fuel will drain onto the diff and then go everywhere if you're not careful! A 19mm fitting screws in to the screen and I found that when I began to loosen the 19mm fuel line fitting, the whole screen came out with it, which works out great! I just cleaned mine with carb cleaner and a toothbrush and it was good to go. I also used my finger to clean out slime that was gathered around the screen opening. Here is a pic of the screen to give you an idea of what to expect.

TMAllison · #14 12-22-2007, 12:36 AM

Have you confirmed that there are no leaks at the delivery valves? Especially #1? That can cause a loud idle.

WINGAS · #15 12-22-2007, 07:59 AM

Jeremy, interesting. Guys I have the SAME affliction. Oddly, I just started the car after a month of sitting and it ran well longer ( about one minute) before deteriorating into a smoky clanky mess. It'll stay that way until its fully warm at 83.

I planned on the tank screen, but never reckoned it had any impact on the "just after cold start" running issue.

BTW, new nozzles, all tested. No change. ( better wot power)

Everyone says GLOWS. but again, the car just started after sitting in sub 0 (c) temps fr a month. It starts GREAT! and runs like new for about ten sencodns adn then.... whomp whompa, like it begins to miss soon after...

Tank is at 1/4 adn I plan on running it out this weekend.

Doe anyone know what the ARA actuator is on these IPs? I'm thiking it's a bad prechamber or a IP that needs service. Or this electrical hookup???

Im was going to give it a compression test first to rule out bad cyl pressures ( althohgh like I said, starts fine and runs new for half a minute).