Major Problem w/ "new" Motor!!! M602 - PeachParts Mercedes-Benz Forum

350SL4spd · #1 07-22-2004, 02:23 PM

Hello all,
I just replaced the engine in a friends 91 300D 2.5 Turbo w/ an engine out of a 93 (same engine #). The "new" engine has a scant 88k mi, but has been sitting for god knows how long. It started up just fine, but ran like sh**; blowing tons of smoke and barely holding an idle. It is very clattery and in searching for the source of the noise, the vibration from it can be felt most strongly in the injector lines btw the pump and the injectors (injectors are new btw).
Now, the other funny thing is that I ran a can of Diesel Purge through it and it ran GREAT while it was running on the purge (still the clatter, but a perfect idle). Now, the car has only been off the road for a month, so I don't think the gas in the tank went that bad...
Going down the road, the boost is there (10psi of it anyway) but no acceleration (non-turbo-like accel). Lack of enrichment? The clatter goes away entirely at about 50mph, but before that it is very loud. Where should I look?
I am coming to the end of my rope here, so any suggestions on what to look for or what might need adj/cleaning after sitting so long would be great!!
Thanks fellow diesel-philes!
-Matt-

TwitchKitty · #2 07-22-2004, 03:57 PM

What does the fuel tank smell like?

350SL4spd · #3 07-22-2004, 04:37 PM

Like the Diesel additive/injector cleaner I put in yesterday...

It sounds like a diesel, just really LOUD. It is the right kind of clatter, just too loud. Could it be one of the "injectors" on the top of the pump?
Or what else?

-M-

#4 07-22-2004, 04:47 PM

Injection pump timing?

Rick Miley · #5 07-22-2004, 04:49 PM

Still sounds like a fuel problem if it ran fine one Diesel Purge. Probably would be worth it to drain the tank and replace with known good fuel in order to avoid trashing another engine.

Boost without power would be lack of fuel enrichment, and you might be lucky for it. After it is running smoother, check the overboost protection device.

350SL4spd · #6 07-22-2004, 05:55 PM

Thanks All!
Car had less than 1/4 tank (and has only been sitting for 4 weeks!) so I just filled it up and put in a good amount of additive. Ran it 25 mi. No improvement. (if it's gonna blow, it may as well be while it's warrantied) It idled good on the purge but was still making a lot of noise, not sure how it would have run under load.
I've been all over the boost control...How does this model enrich??? Does it pull a vacuum on the ALDA? Or a pressure? Or does it do it somewhere else? I can't seem to get either at the ALDA, even though vac supply is good. Any thoughts on where to look in the enrichment circuit would be great!!
Injection timing is a possiblity, if I can figure out how to set it (looks different than my old 617).
Anyother ideas as to WTF is malfunctioning are quite welcome!!
Thanks!

-M-

Rick Miley · #7 07-22-2004, 06:01 PM

The ALDA enriches with pressure, supplied from the intake manifold. Check the banjo bolt to see if it is plugged.

As for injection timing, our resident 602/603 expert is gsxr. Seek out one of his posts and see if it has a link to his web site. There might be something on there timing the pump.

william rogers · #8 07-23-2004, 02:38 AM

I'd sure check IP timing............

William Rogers........

350SL4spd · #9 07-23-2004, 02:21 PM

After a few test, the ALDA seems to be completely non-functional. I am going to replace it w/ the one from the blown motor. I don't think this will get rid of the (scary) noise, but it's a start.
I am also going to check the IP timing...If I can figure out how. Any links would be appreciated!
-M-

Pete Burton · #10 07-23-2004, 04:18 PM

Check the "new" injectors again by bringing them to a Bosch authorized facility or someone else properly equipped and have each injector in the set tested for opening pressure(pop), atomization and spray pattern. All should open at nearly the same pressure (depends on your engine, but roughly within 3-5 bar). It cost me $40 last month to check 10. Look into prechambers for crud buildup, etc as best you can.

Rick Miley · #11 07-23-2004, 04:22 PM

Poke around here: meimann.com

Dana B. · #12 07-23-2004, 08:22 PM

I had a mechanic once attempt to change some leaking seals in my IP -- and messed up the timing so badly it sounded like a Cummins. Never did get it right and had to get a rebuilt injection pump (not cheap).

Good luck.

350SL4spd · #13 07-25-2004, 12:54 PM

Replacing ALDA, did nothing for her. With the amount of blue smoke I'm blowing I am starting to the think the oil rings are totally f***ed. Going to check the compression on all 5 then the IP timing....
"She's all ready to go. You should be able to drop it right in and be drivin' in a day!"
yeah right...

-Matt-

gsxr · #14 07-24-2007, 10:57 AM

Quote:

Originally Posted by Rick Miley

Poke around here: meimann.com

FYI, that URL has moved... it's now here:
http://www.w124performance.com/images/

BTW, I had a similar issue with my 602.962 when it first arrived in November 2006. I took some video of the smoke screen it spewed, check these out:
http://www.w124performance.com/images/cars/93_300D/purchase/bad_fuel1.wmv
http://www.w124performance.com/images/cars/93_300D/purchase/bad_fuel2.wmv

I believe it was a combination of the following things:
1) Questionable fuel from the southeast (smelled funny, red tint, etc)
2) Cold ambient temps (20-40°F)
3) Injection timing retarded (approx 17° ATDC, spec is 14°)
4) Cam timing retarded (approx 8° stretch compared to the new chain)

It ran OK on Diesel Purge, but still had issues when not on Purge. I drained the tank & put in fresh fuel, that helped, but didn't cure the problem. A new timing chain, and correct IP timing, did the trick. It's been fine ever since. The MPG is a little low (30-32mpg) but that could just be the fuel we're getting from the refineries at the moment - hard to tell. I need to put more miles on it.

rrgrassi · #15 07-24-2007, 11:17 AM

Do you know the history of the car the "new" engine came from? Was is a "LoveCrap" or some other SVO/WVO car? What condition are the pre-chambers in? I know on the OM617, if the valves are tight it clatters more.

Since the engine you have has hydraulic lifters, are any of them "frozen", or leaking down?