new balanced injectors nailing (video included! ) - PeachParts Mercedes-Benz Forum

pdrayton · #1 05-12-2007, 11:51 PM

I put new injector nozzles and balanced them all to 140 bar (it's a 92 300D 2.5 turbo.)

It had been nailing a little bit, but now it is nailing a LOT!

But only when idling. When I pull off it goes well - very smooth and good power. At high revs it puffs black smoke out (Like in an italian tune up).

I tightened down the injectors a bit more to be sure they weren't the cause of the nailing, but still, they're nailing. At least I think it is nailing. It could be the hydraulic lifters. I replaced about half of them 6 months ago, and they seem to have been fine since then, but you never know, it could be them, but why would they suddenly get loud when I balance the injectors?

The old injectors where at about 1600 psi (110bar - very low, these are 135-145 bar injectors) and now they're at 140bar, so could that be doing it?

The other thing I'm thinking it could be is that I'm using the mobil 1 extended synthetic oil and it's not specifically rated for diesel. But it was making noise before I used that oil, just not so much.

Anyway, I probably needn't have blabbered so much, the videos will tell all.

The other possibility is that the noise is from the splined collars that hold the threaded piece that the injector screws into is leaking on 2 of the injectors.

Also, the nailing is hard to locate. It sounds like it is coming from the whole top part of the engine - I untightened each injector line in turn and the noise continued. Also, removing the oil cap didn't increase the noise ( I thought noisy lifters would be more noisy with the oil cap off).

OK, enough blabbering. Please you with the experienced ears, have a listen and a look and tell me what you think,.

Last blabber - injector 1 needs a new threadfor the injector to screw into, so that could be contributing. I tried to buy the part, but the dealer couldn't find it and when they found something it looked like the wrong piece. I'm talking about the piece that the injector screws into on the head. It's held down by a splined ring collar.

Thanks.

Movies at
http://www.pauldrayton.com/uploadfiles/merc/nailing/nailing.html
Thanks

arew264 · #2 05-12-2007, 11:56 PM

What brand were the injector nozzles?
I think I have read that bosios are known to do wierd things for the first 500-1000 miles, then work really well for quite some time.

pdrayton · #3 05-13-2007, 12:01 AM

Ahh yes, I knew I forgot something - the nozzles are Bosio replacements for the 265s. The bosios I put in my 240D didn't do anything weird. I ordered some german Bosch nozzles, but they didn't arrive, so I used these Bosios.

pdrayton · #4 05-14-2007, 07:35 AM

I adjusted the timing (by ear - cringe). When I advanced the timing quite a bit (ip moved up about 1/4 inch at the adjusting screw), the nailing got much quieter.

Now I'm thinking it is just the usual cam followers that are making a noise.

Have a listen to the video, please and tell me if I'm wasting my time putting in new cam followers. Pleeeease!

http://www.pauldrayton.com/uploadfiles/merc/nailing/nailing.html

turbodeezl · #5 05-14-2007, 01:46 PM

Let me know what you find out cause mine nails a lot when cold, even after I put in new Bosio nozzles. I just haven't had time to balance them or run diesel purge through.

'91 300D 2.5

James L · #6 05-14-2007, 04:06 PM

Watching this thread pdrayton, mine does some nailing also, along with my previously stated boost pressure (I too am stumped and still troubleshooting!) I plan on taking the complete intake manifold and EGR off for a good crud/soot cleaning. Could this contribute in nailing?

I replaced #1 and #2 leaking injectors with Bosch remains (from Phil) and no more leaks but same nailing. Replaced IP injector nozzle o-rings and seals no-change.

Tell us more about the IP adjustment screw.

pdrayton · #7 05-14-2007, 06:20 PM

I'm no expert on it, but timing is very important. Setting the timing is described in the FSM which is at (sssshhhhh)

http://www.pauldrayton.com/uploadfiles/merc
select 07.1-8300 - it tells all about moving the IP, which is easy once you figure out the easy way to get your hands around stuff to undo the bolts holding the IP. BEfore you move anything though, mark the ip and engine block with a line so you know where you started from.

I'm going to try get the machine for adjusting timing exactly and replace my cam followers. Cam followers are a common noise maker that sound a lot like injectors (in my experience anyway). You might want to look in the FSM about how to check the cam followers (basically you take off the oil cover and push them down one by one to see if they collapse. If they do collapse, they're shot)

pdrayton · #8 05-19-2007, 12:07 PM

Bump....

Any ideas whether this is cam followers, timing or nozzles in this video?

http://www.pauldrayton.com/uploadfiles/merc/nailing/nailing.html

pdrayton · #9 06-14-2007, 08:28 AM

I'm thinking the knocking that goes away with time when you put in new nozzles could be the seal is not good, and in time it cokes up and makes less noise.

I am now thinking the noise from my injectors/oil cover area must be prechambers. My reasons are 1. Brian Carlton described the follower noise as a regular and sharp metallic sound. My sound is not regular or sharp.
2. Injectors/prechamber noise sounds louder near the rear of the wheel wells. Mine does.

So it must be injectors or prechambers. Since the sound isn't coming from one source that I can identify by undoing the injector lines one at a time, I am assuming (yes, dangerous) it must be prechambers. Guess I'll have to pull it out and see. I have the tool rented from someone on the forum. And I'm going to get a slide hammer and hook it up to an old injector body and have a go at getting the prechamber out and putting a new seal in for the injector. There is a crush washer / seal stuck in there and it's not in good condition. I read some guy fixed his leaking prechamber by taking it out, cleaning it and aputting it back. If that doesn't work, there are pcs for sale for under $100 on the internet.

Do you see any illogic or errors in my reasoning? Is there a better check for pc problems?

Thanks

Paul

WINGAS · #10 06-14-2007, 02:18 PM

Paul,
I BELEIVE my "new" oil burner has PC problems as well. The only way I;ve read about here to check is visual, literally to peer into the injector hole and see what shape the PC is in. And then, of course, their removal.

Is there a proctologist in the house!

RIght now, Howe's Meaner Cleaner is radically mitigating the engine's issues until this winter when I do what you are about to.

Cervan · #11 06-14-2007, 04:05 PM

sounds allright to me. i think your retarding the timing, causing it to burn later, less power, more smoke. less burn meaning less nailing. just drive it if it gets any worse then take a look at it.

pmckechnie · #12 06-14-2007, 04:46 PM

I went through the same thing on my 91 300D when I got it. I had injectors cleaned and checked and same thing. I did a Diesel Purge and while the purge was running, the engine was as quiet as a gas motor. That told me it was not a mechanical problem but was nailing. I haven't messed with it since. It runs good, gets good mileage (If my wife drives it, not as good when I drive it). Try Diesel Purge and see if it is quiet while running on the purge. If it is, don't worry about it.