Hi,

My Indy told me that listening to the cold idle, that I have a slight injector leak. I could not tell, my 82 sounds like all my other w123 diesels.

I do know that I get a failed start every morning because I let off cranking a tad bit earlier than I should.

Anyway, how would I diagnose if an injector is "leaking"? Can I do it with a stethescope or something?

I plan to send my injectors to CSW to clean and pop test, likely install new nozzles too. Is there a way I can diagnose which injectors may have issues before sending them out?

Id rather get my current ones rebuilt unless there is really good reason against it. I'd probably ultimately do my 240D as well, but at 74k, I assume nozzles, if anything besides cleaning and pop testing would suffice. the 240d does run rough ifg I back the idle all the way down...

Thoughts?

Thanks!

__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)

Unless it's leaking fuel, have them all tested as you're going to anyway.
At 74k, you should need any maintenance.

__________________
83 SD

84 CD

the 74k one Im just trying to do anything that can be best practice, and also help to smooth the strong shake when idle is turned all the way down.

If my indy hadnt said that he heard what indicated an injector leaking, I wouldnt necessarily even be up on doing these on a 160k engine, though reading through the archives and doing some searches, it does seem to be a good idea at roughly that age...

__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)

Hi
I'm not clear what your indy means by injector "leaking" If you don't see any fuel on the outside or bubbles where it screws into the head - maybe he thinks the nozzle isn't shutting off correctly and fuel is dribbling into the prechamber. Seems like you would have a miss or some black smoke were that the case. Pop testing would tell if your injectors have a good spray pattern and are popping at the correct pressure. You can make a quick check of injectors by cracking the hard lines at the injector - one -by-one, with the engine at idle, to see if one cylinder reacts differently from the others.

Starting failure sounds more like a glow problem - or perhaps a compression problem. Both not hard to check as a DIY - see threads.

Good Luck,
Joseph

Thanks, well aware of glow and other system operation, compression effects, etc.

Here I am merely trying to put 2+2 together wrt an injector leaking INTO the engine. We were not talking about external leaks.

My comment on it not always catching is a separate issue, call it irrelevant for now, it was not part of my conversation with my mechanic.

If I can determine somehow what injector may be leaking, Ill be that much smarter. FWIW, no black smoke at startup, and always a smooth idle on the CD. He characterized some tapping, which I couldnt really hear or isolate, as a sign of a leaking injector.

__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)

Hi
I just don't understand the idea of diagnosing a leaking injector just by hearing a tapping sound. Of course a nailing sound is common with injectors that aren't spraying right - maybe that's what he means - rather than one that is leaking.

On the other hand, I'm hear to learn. Please let us know what you find.
Joseph

Call me stupid but I dont know what a nailing sound sounds like... Therein lies half my problem, I dont know what to listen for beyond typical diesel knocking sound.

Im here to learn too, hopefully some insight can be shed as to what to listen for...

__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)

Nailing = tapping (not slamming) two hammer heads together in time with the engine.

Normal 'clacking' = hitting the wooden handle of one of the hammers with the head of the other.

Quick test - open the hood and from a warm idle, slowly bring up the idle by hand. Do you hear an increase in a higher pitched almost metallic sound, either intermittent or exactly in time with every revolution? Does it go away at 1600-1900 rpm?

ALSO, 'internal' leaks are more likely if you consider both the needle and the bottom of the spacer disc to top of nozzle body are TWO places leaks can happen - vs - top of spacer disc to bottom of upper injector half is one place.

__________________
1987 300D (230,000 mi on a #14 head-watching the temp gauge and keeping the ghost in the machine)
Raleigh NC - Home of deep fried sushi!

Hi
Thank you!

Please be so kind as to explain the "quick test" a little more. What does it mean if the sound goes away at 1600-1900 rpm? And why would that happen?

Also, does an injector with internal leaks - have a distinctive sound?

Regards,
Joseph

As the RPM come up, the marginal injector(s) get more fuel - helping to quite the nailing. Idle and just above idle is where nailing will be easiest to hear.

I don't really think an internal leak/dribble will sound very different than a low pop pressure - IE: they both tend to nail BUT there might be some 'old timers' here who know how to tell them apart.....?

__________________
1987 300D (230,000 mi on a #14 head-watching the temp gauge and keeping the ghost in the machine)
Raleigh NC - Home of deep fried sushi!