Is this injectors (sound file attached) - PeachParts Mercedes-Benz Forum

pdrayton · #1 01-11-2007, 09:38 PM

I can hear the old pros groaning "oooooooaaaaawwwwwrrggh, another newbie with a post about injector's nailing".....

Well, I've read all the posts I can about nailing and if a picture is worth a thousand words, then a sound file must be worth at least 500. It is one thing to read about what an injector nailing sounds like, and it's another to hear it, and someone says, yes that's your injectors nailing, service them. Or no, that's your timing. Or something else.

So, there is a mp3 of the sound of my car making a clacking sound, here

There's a fair amount of ambient noise because I am driving the car at the time - it only makes the noise while driving at about 1/4 throttle, less at other throttles, hardly any at full throttle or idling.

The funny thing is the sound is hardly there at all when I run it (83 240D) on WVO. I read there is some difference in the timing when using WVO - it burns slightly later or something. The sound is really loud with diesel, which I used today. I get good mileage - about 30mpg.

I would really appreciate it if someone with experience of what nailing or bad timing sounds like could give it a listen and tell me if they can hear what it is. Really appreciate it. I don't want to take out the injectors and and balance them with a pop-tester if they are not the problem. Or start messing with the black arts of injector hoedunkery if I don't have to.

BTW, I checked the timing chain stretch with the alignment on the camshaft and it seemed spot on - almost no stretch at all. If that's relevant, I don't know, this is kinda out of my experience range. I have half the parts, and probably half the knowledge so far on how to do the injector balancing, so I can do that if that is what is required. I did do a millivolt test, and there was quite a range of voltages from the glowplugs. But after thinking about it for a while, I thought what you should really compare is the ratio of glowplug resistance to voltage, not just the voltage.

Thanks chaps, and chapettes.

Knightrider966 · #2 01-11-2007, 09:49 PM

I've noticed that biodiesel will make diesels run quieter than Dino diesel. I can't tell enough from your audio to know if anything is wrong with your auto. Was this idling when you recorded the clacking noise? Diesels clack and there is not much you can do about it. It's just their nature being compression ignition engines! How close were you to the motor?

kerry · #3 01-11-2007, 09:52 PM

I couldn't hear any nailing on the audiofile.

mespe · #4 01-11-2007, 10:17 PM

That sounds more like a loose air cleaner bouncing around.,,, injector knock sounds more like a hammer hitting the block,,, or maybe more like bad bearings. I had injector knock that went away after I kept driving the car,,, The harder I drove it, the quicker it went away.

pdrayton · #5 01-11-2007, 10:23 PM

It never used to make this noise, so I'm thinking it's not normal. I've been running it on WVO for the past 5000 miles or so, so I'm wondering if it's something to do with that. Maybe time for a diesel purge.

I was driving the car at the time I recorded that. The mic was held near the accelerator pedal (head above the dashboard). I know it's kinda hard to hear it properly. Maybe I'll try get it to do it when I'm not driving it, at least a little, then it will be clearer.

I don't think it's the air filter housing becuase the rattling is directly proportional to the revs. Plus, I checked the air filter - it was loose, but I epoxy steeled it in and it's solid now. I also got a K N filter. Expensive, but it seems to have made a noticeable difference in mileage.

yellit · #6 01-11-2007, 10:35 PM

This rings a bell.....here we go....had a very obvious pinging in my 80 240D when driving at a constant speed.....from day one couple years back...my first much loved diesel....
Sounded almost like timing chain slap on the timing cover or sharp metallic nailing...Sounded a lot like the early 1970's cars pinging from detonation with throttle increase... but more evenly spaced like it was at the rate of one of the cylinders injection pulse.....Almost drove me crazy.....I hate pings...
Swapped the injectors around...no change...diesel purge,IP timing,New Timing chain/rails/tensioner,biodiesel,truck stop diesel,fuel additives,vac pump rebuild,glow plugs,compression tests..... you name it....this thing beat me down....depression was setting in....I either had to sell the car and start therapy...or fix it somehow...
The biodiesel did seem to run a bit less (pingy?)...
Finally pulled the injectors and had them tested at the Bosch IP Shop.....
The original #3 injector was leaking and had a nasty stream coming out of it instead of a mist .....very different from the other 3 injectors...
I put in a set of used, cleaned & tested injectors and the wretched pinging stopped....I could not believe it...Sounded smooth as butter at all speeds...

This problem only happened at constant speed.....accelerating and slowing and idle it was too faint to hear......

I was about to pull the engine because I had done everything else with no results...thought it might be that sheet metal plate cracking on the Torq. Conv/flywheel....Just some friendly info from my past hellish pinging nightmare....Injectors were much easier to change than the timing chain.....hopefully the above info may save some poor creature the time, money and headaches....

Tymbrymi · #7 01-11-2007, 10:39 PM

Quote:

Originally Posted by pdrayton

There's a fair amount of ambient noise because I am driving the car at the time - it only makes the noise while driving at about 1/4 throttle, less at other throttles, hardly any at full throttle or idling.

Does it smoke any while it is making that noise? How easy is it to start? Is it more RPM based than throttle based?

I had a problem where the car was always hard to start and from about 1100-1400 RPM (or so... its been a while) it would start knocking horribly (to the point of running rough and shaking the car). It would also smoke at the same time (the smoke wasn't black, but I can't remember if it was grey or bluish smoke). At idle or higher RPMs it did just fine. I did everything to try and fix it... new GPs for the starting, fuel filters, new injector nozzles, pop-tested and verified the spray pattern, etc. Didn't change any of it. When I replaced the IP, the problem was gone.

Keep in mind that statistically the IP very rarely fails. Most IPs outlive the original engine... However, your knocking noise sounds similar to what I experienced, and if you have any of the other symptoms... it might be something to put on the list.

Before you do that get your injectors tested.

No clue about the WVO

pdrayton · #8 01-11-2007, 11:06 PM

thanks Yellit - I think your experience might save me a lot of time. Thanks for sharing. I think I really need to make that pop-tester and check out the nozzles.

Tymbrymi - it starts really well - even WVO on cold mornings. It doesn't smoke while driving, it only smokes a little grey smoke when idling. It is RPM based definately. I'm wondering if this could be becuase of the IP working harder with a viscous WVO and I should get a aux pump. I think I should check the nozzles first.

Tymbrymi · #9 01-12-2007, 01:14 AM

Quote:

Originally Posted by pdrayton

Tymbrymi - it starts really well - even WVO on cold mornings. It doesn't smoke while driving, it only smokes a little grey smoke when idling. It is RPM based definately. I'm wondering if this could be becuase of the IP working harder with a viscous WVO and I should get a aux pump. I think I should check the nozzles first.

Definitely check your nozzles first

I had already done everything else.... injectors are much more likely to go south than the IP anyway.

Best of luck with it and let us know how it turns out!

greasybenz · #10 01-12-2007, 01:21 AM

Are you heating your wvo? if not then that explains the sound. This is whats happening to your injectors.

Get the injectors pulled and cleaned at a reputable injector shop. And heat the wvo.

Darren · #11 01-24-2007, 06:52 PM

The coking on theat injector does not look terrible to me. I have seen injectors that have only ever seen diesel with far more carbon build up on the surface than this.

If you are going to go to the trouble of pulling injectors and taking them to be tested, if the car has not had new injectors in the last 100,000 miles or so, it is good practice to have new nozzles fitted if you run SVO I would highly recommend replacement.

I recently fitted my own nozzles. Got some Bosch nozzles (made in India) that were rubbish. Tried some delphi nozzles which all tested good.
For SVO use I would recommend DN0SD261 for the older cast iron head engines (OM617 or 616) and the standard DN0SD265 for the alloy headed engines (OM601 & 602 fitted to cars for commercial vehicles use 261 nozzle)

I hear good things about the Bosio nozzles and would also consider fitting these.

Best

Darren

www.vegburner.co.uk

DieselAddict · #12 01-24-2007, 07:01 PM

I concur that it's the injectors and I'm almost certain. I had the same symptom with my ex-82 300D when one injector started pissing instead of spraying. I also concur that the VO should be heated, otherwise your injectors will be coked in no time.

pdrayton · #13 05-02-2007, 08:41 AM

Darren,

You recommend the DN0SD261 for the 616 with WVO. Fine, I'll get those.

For my 602.962 (1992 300D 2.5 Turbo - aluminium head) passenger car, you recommend the same thing - DN0SD261? or the 265? It's running on diesel but I am considering moving it to WVO. What's the difference between the 261 and 265? Why do you say the 265 is for commercial vehicles?

OK, that's more than 'a question'!

But the basic question is - should I get the 265 or the 261 for my 602 passenger car?

Thanks

vstech · #14 05-02-2007, 09:00 AM

the audio file sounds to me like an exhaust leak.
John

pdrayton · #15 05-02-2007, 09:05 AM

John, it was the injectors - I have Bosio's in there now and it is much quieter, but I don't trust them and am going to get some Bosch nozzles as backups. Also trying to get some nozzles for my 602, but not sure if I should get the 261 or 265 if I am thinking of running WVO in it.

I run WVO in my 240D and it should get the 261 which the experts (Darren from vegburner and Alastair aka H.C.II) say is flat cut and good for the WVO and torque on a 616.