Woud you ever recommend against new Nozzles?! - PeachParts Mercedes-Benz Forum

MercFan · #1 08-02-2006, 10:20 AM

I've got 197K+ on my car - it's fairly new to me, I've had it since May and overall I'm very pleased. I've been working on it it drives very respectably now, but it has few hiccups. One of them is that it has 2-3 misses each time I start it cold. It also clanks/pings/nails (don't know the right term) MOSTLY when it's cold - though on occasion I've heard the clanking/pinging/nailing noise after running it on the highway...

Here's what I've done to it so far:
1) New air filter
2) New spin-on and pre-filter (fuel)
3) Banjo bolt cleaned, lines replaced to ALDA, overboost cleaned
4) New switchover valve
5) One new glow plug
6) Valve adjustment (all exhaust valves were very tight, all intake ok)
7) Timing chain stretch measured - still need to post pictures and get confirmation of the results...
8) Few odds and ends (new belts, sway bar links, steering fluid changed, diff fluid changed).
9) Diesel Purge (late EDIT)

I was hoping that the valve adjustment would reduce the pinging noise and the 'clankiness' at start, but no... I suspect that in the fall/winter when the temps drop the clankiness will be even worse, so I wonder: should I plan on getting a set of new Injector Nozzles (Bosio)? I suppose I should do the investigation and crack one injector at a time to isolate the problem, but I'm a little chicken messing with the hard lines...

Would you ever recommending NOT getting new nozzles? Based on what I've read here, it might help...

techguy512 · #2 08-02-2006, 10:36 AM

Quote:

Originally Posted by MercFan

It also clanks/pings/nails (don't know the right term) MOSTLY when it's cold

For me, a diesel purge reduced the clanks/pings/nails by 25%. Then mixing biodiesel into regular
pump diesel at about a 20% ratio reduced it by another 60%.

I'm down to 15% clanks/pings/nails and only at absolute cold start. After a minute of warm-up it sounds
like a sewing machine.

Bob
'82 300D, 165K mi.

techguy512 · #3 08-02-2006, 10:37 AM

I should also say that I pulled my injectors and had them tested for pop pressure and spray pattern.

All were good.

MercFan · #4 08-02-2006, 10:51 AM

Quote:

Originally Posted by techguy512

For me, a diesel purge reduced the clanks/pings/nails by 25%. Then mixing biodiesel into regular pump diesel at about a 20% ratio reduced it by another 60%. I'm down to 15% clanks/pings/nails and only at absolute cold start.

Sorry, forgot to mention that I also DID do the Diesel Purge (2 cans) - it helped for a little while (it seemed) but it's more pronounced now.

Mine also smoothes out considerably after the warmup - I don't usually hear it after it warms up.

I suppose I should pull the injectors and have them tested FIRST before shelling out the $$$ - just will need to get the new heat shields I guess. Wonder if the local dealer will want a lot for them...

Endust · #5 08-02-2006, 10:56 AM

When its cold and nailing crack the injector hard lines one and a time and find the cyl thats nailing. Then pull that injector and replace or rebuild it. I had an injector in my 240 that got beat to death by a prechamber disintegration. I put in a bossio nozzle. The first few hundred miles it nailed on cold start but has been quiet since then. If you find one thats nailing I would put a new nozzle in it and call it done. The nozzle job takes about 15 mins.

Jim Anderson · #6 08-02-2006, 11:16 AM

By coincidence I needed the injector pump rebuilt because it started leaking badly. When I put the pump back in the leak had stopped and the cold missing went away.

MercFan · #7 08-02-2006, 11:19 AM

Quote:

Originally Posted by Jim Anderson

By coincidence I needed the injector pump rebuilt because it started leaking badly. When I put the pump back in the leak had stopped and the cold missing went away.

Oh no, I HOPE it's not the pump... that's big $$$ and headaches... Will try cracking the suspect injector and go that route first...

TwitchKitty · #8 08-02-2006, 11:27 AM

Either build or buy an injector tester and do it yourself or find a shop that knows about the pintle holes in our injectors (most don't) and let them do it. Assuming that a diesel truck and equipment oriented business will fix your injectors correctly is a crap shoot. Do all of them right once and you will likely never have to give it another thought. Spray volume and quality are the two key factors in diesel performance. Too often in this forum people erroneously treat them as issues to be avoided and will go to any length to avoid them.

If you don't need nozzles they are a waste of money. Test the old ones and go from there.

Some reading for you:

http://www.peachparts.com/shopforum/showthread.php?t=155294

Hatterasguy · #9 08-02-2006, 11:37 AM

On any of these cars I recomend pulling your injectors having the pop pressure and spray pattern tested. If any fail rebuild them until you have a good set.

These are all old cars, I doubt that all 4,5, or 6 injectors would pass such a test.

Brian Carlton · #10 08-02-2006, 05:33 PM

Quote:

Originally Posted by Hatterasguy

On any of these cars I recomend pulling your injectors having the pop pressure and spray pattern tested. If any fail rebuild them until you have a good set.

These are all old cars, I doubt that all 4,5, or 6 injectors would pass such a test.

Apparently, that's exactly what most shops supposedly do. But, if you have any respect for Beagle and his opinions, leakoff is far more important than pop pressure. If the set of injectors varies 5 bar or so..........it's not going to make a bit of difference in the performance of the engine.

Far too many folks are worried about getting the pop pressure perfectly correct across all five and ignore the leakoff because they can't properly check it.

Hatterasguy · #11 08-02-2006, 05:36 PM

That shop I use does check leak off. Solution if yours doesn't is to find a better shop!

Brian Carlton · #12 08-02-2006, 05:37 PM

Quote:

Originally Posted by Hatterasguy

That shop I use does check leak off. Solution if yours doesn't is to find a better shop!

........but you fail to mention this in the above post (#9)??

Hatterasguy · #13 08-02-2006, 05:41 PM

I forgot at the time.

FineOlBenz · #14 08-27-2006, 12:23 PM

Anyone know of a shop in California that does inhector testing? I have #4 (of 5)that is dead at idle. I also notice some leakage around the prechambers of #1 2 & 3. Or is that my imagination. It appears to be oil but bubbling. Would that be internal pressure or heat bubbles? Any ideas?

jshadows · #15 08-27-2006, 12:32 PM

Ok, that brings me to something I've been looking for. I've got a set of injectors with shot nozzles (needles crushed, etc...I do not need to test them to figure this out). I'll probably rebuild them with some bosios and then sell them for a fair price. They're 603 turbo injectors.

My question is, who the heck sells the shims if you want to adjust pop pressure? I've got a tester but without the shims I can only verify where I'm at.