I brought my 1983 300TD to a long-time trusted mechanic who fabricated replacement lines going to the SLS valve, as the old ones had rusted and were leaking. That all turned out fine-he's worked on the car a number of times-and while it was there I had him perform 2 other tasks: cleaning the tank screen filter, and installing a new air filter (which I supplied).

I picked up the car Friday afternoon but only drove it few blocks home; I didn't notice any problems but I probably didn't exceed 25 mph. Today I drove it on the highway for the first time, and it wouldn't go faster than 40 mph, floored. (before this it would happily go 85 mph and felt like there was more speed available if I wanted). When I got home I opened the hood and found that none of the clips holding the air filter cover on were fastened, and also there is a pipe coming out of the bottom of the air filter housing that wasn't attached to a pipe that leads downwards from the air filter to somewhere on the engine (?) , so I attached that pipe and fastened the clips that hold the top. My thought was that one of his employees got distracted (it was a Friday afternoon) and forgot to finish the job...anyway just to be thorough (cause it felt like fuel starvation) I also changed the small fuel filter-even though it was only slightly dirty.

I took the car on the highway and it seemed *marginally* better but I could tell the turbo wasn't coming "on" (there's always been a noticeable increase in power and a sort of subtle "growl" as soon as the engine reaches 2000 rpm, and there was nothing like that now). In fact it almost seemed like it was running out of fuel..barely made 45 mph floored. Coming off the highway and onto a local street it started to idle rough, and wouldn't go more than 10 mph for a few minutes...limped home and it got a bit better. Anyway it's dark now (and cold) so I need to wait till AM to check it out.

The big fuel filter (I can't remember if that one is called the primary or the secondary?) was changed about 15000 miles ago, but because I've had so much junk coming from the tank-I've changed the little one probably 5 times since I changed the big one- it's probably time to change that too (and I've got one I can install in the AM). But...I'm thinking there's something else going on, which is the reason for my question.

Is there something that, if disconnected by accident, could cause this loss of power and lack of turbo activity? Like if someone yanked the air filter housing (they apparently did, because that small "pipe" was disconnected) could something else come off? I see in the Haynes manual there's another, larger hose ("turbocharger intake pipe") attached to the housing; my guess is that could be a pretty significant factor, if it was detached. Was it even necessary to detach the housing in order to replace the air filter (??)

Sorry if I'm thinking out loud here...obviously I'll check it out tom'w. I really don't feel like dropping it off at the mechanic again and being without the car for the day, especially if it's some stupid oversight by an "underling" that I could take care of in 15 minutes...thanks for any input!

If the air cleaner was wrestled off it may have damaged the hose at the back end of the intake manifold that attaches to a banjo bolt. Look along the firewall for a white/opaque vacuum line and check it at both ends.

Also check the vacuum hose on the back/top of the injection pump that is about 1.5" long and is v or u shaped for collapsing.

Have someone push the accelerator pedal to the floor and confirm that injection pump goes to full throttle in case linkage was knocked off or installed wrong.

Did they fuel the car? Any chance of bad or wrong fuel was added?

Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

My first action would be to replace the secondary fuel filter. A clogged filter can cause exactly the symptoms that you have described.

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When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

Agreed, change the spin on secondary fuel filter (Fill it with fuel first to avoid having to use the hand primer pump too much). Then look for any of the loose lines mentioned above.

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2012 Mercedes ML350 Bluetec 91K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 231K (mine)
1998 Volvo S70 T5 Turbo 196K (kids)
1994 Ford F150 4WD 249K (firewood hauler)
1983 Mercedes 300D 376K (diesel commuter)

You might pull that elbow pipe off the turbo and see if you have a rag in the intake.

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- Greg -
1973 220D, The Prodigal Benz
1974 240D

Since the tank screen was touched check for possible air intrusion, line kinks, or leaks around there.

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1985 300D
The rest:
1957 MGA (comatose)
1965 Falcon (sleeping)
1966 E-100 (rust test in progress)
1976 Ford 3400 D Tractor (workhorse)
1978 Mercury Zephyer (5L playtoy)
1995 Isuzu NPR D (fetcher)
1998 Subaru Legacy (Spare)
2000 Toyota Sienna (School bus)
2008 Toyota Prius (Commuter)

You might want to check the switchover valve to see if a vac hose came off. It talks to the ALDA. Or if they got the vac hoses mixed up that would hurt your acceleration.

It's kind of funny, when I picked up my car from body shop after a week, it had piss poor acceleration, even though I filled up 3/4 tank with diesel right after picking it up. I've found that the wastegate arm was loose, the retaining E-clip was lost.

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The 300SD was massively down on power, idle and low speed were just fine. Changed the big filter and it was back to normal.

Michael

thanks to all for the great suggestions...I did put the skinny hose/pipe/whatever back onto the bottom of the air cleaner (it attaches to the plastic thing that sits in the middle of the air cleaner), but I also changed the large fuel filter (I guess that's referred to as the secondary filter, as it comes AFTER the little transparent one in terms of fuel flow) and that made all the difference-once I actually got the car started, that is...

I didn't have any diesel handy, but I had some kerosene, so I put an ounce of so of MMO into the filter and then filled it up the rest of the way with kerosene. Pumped the primer pump (which is a new Bosch one I put in and seems to work very well), but the car just didn't want to start for about ten minutes of trying (giving time for the starter to cool down between tries). It's NEVER been hard to start-even in single digit winter weather-so I was worried for a bit, but I thought maybe it just wasn't happy with the kerosene..once it finally started I let it warm up a couple of minutes and drove to work, and all was well-it ran like it should.

The thing that threw me off was that before bringing it in, it was running fine; I didn't think the dirty/clogged fuel filter would *suddenly* bog the car down that much, that quickly, so I was looking for other reasons. My only theory is that perhaps removing the tank screen to clean it might have dislodged some sludge/goo/gunk that then made its way into the filter when I drove it home from the garage. Or maybe that's just the way it goes with those filters...great, good, good, good, dead LOL

sorry, but I don't know all the terms mentioned in the replies (elbow pipe, wastegate arm, switchover valve, ALDA, etc.). I'm really pretty ignorant about most of this stuff. I'm trying, but I'm old and getting stupid fast...

Glad you got it figured out. That spin on fuel filter will cause the car to run lousy once it gets dirty. Anytime the car is down on power like that, the first thing I check is that filter. A tip I learned when pre filling it is to fill it, and then let it set for about five minutes and you will be surprised how much more fuel it will take. Repeat that process until the filter stays full after sitting for five minutes. The car will usually start right up with maybe a couple misses or stumbles but that should be it. I know it sounds nutty to ask, but since it started so hard, are your glow plugs working correctly? Try this website for some good maintenance tips and procedures Mercedes Diesel Maintenance tips

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2012 Mercedes ML350 Bluetec 91K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 231K (mine)
1998 Volvo S70 T5 Turbo 196K (kids)
1994 Ford F150 4WD 249K (firewood hauler)
1983 Mercedes 300D 376K (diesel commuter)

Glad to hear it’s up on its feet again. In our case, it went from good to bad in just a couple of days. You may be on the right track with something getting stirred up when the screen was pulled.

Michael

Once upon a time, I was on a road trip when I came upon a truck stop selling diesel for well below the going price. So I pulled in and topped off. Leaving the station, the car would not get over 45 mph. And it got worse as I continued.
So...yes, fuel filters can clog quite quickly. (I eventually cut mine open and found that it was filled with a substance very much resembling mud.)

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When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

All 617 cars should be equipped with a small tool box containing 1 spin on filter, 2 primary filters, a 17 mm open end wrench to bleed the injectors, pliers, wire cutters and injector return lines.

I had driven from Mid TN to Chapel Hill NC when the car was new to me. I happened to buy an 00 Dodge Cummins on that trip. I was in the truck and wife was driving the SD back home when in Wilmington it suddenly wouldn't go over 40 mph.

This was when we didn't have good browsers on our cell and I didn't know any better. It was also a Sunday. I ended up renting a U-Haul and dropping the drive shaft in case the tow with back wheels on the ground would mess the trans up. Temps were high 90s and a flat bed was unavailable. It was also Sunday. We got a hotel and came home the next day. 15 minutes or less would have been spent changing the filters had I known.

Lesson learned. There are other parts you should keep just in case ie belts etc but having those fail on a trip is usually because of PPM.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

Glad you got it!!!

Tangofox007 wins with a psaboic gaining an assist??? Not sure how to count that...


Drive on!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer