Hello. I have VERY little torque at low rpms. At a little over 2000 rpms the power comes on strong (turbo kicks in) and the engine behaves like it should. I have changed the filters, adjusted the valves, checked the timing chain stretch (2 degrees), pop tested the injectors, cleaned the lines to and from the ALDA and the switchover valve and adjusted the linkage. I am about to check the pump timing. Does anybody have any insight on this? (yes, I've done a search)

I should add that sometimes it idles rough and literally cannot get out of it's own way. Other times it idles well and has a little power, but still not much.


Thank you!

1984 300SD
replacement engine from 1984 300D
running diesel

__________________
r2

'85 300SD 193k miles (parts)
'81 300SD 400k miles-sold
'84 300SD 205k miles-sold
'84 300TDT 270k miles-sold
'80 300CD 200k miles-sold

Have you checked your Injection timing?

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

Have just come back from the junkyard with an injector line to check the pump timing via the drip method as per my post.

__________________
r2

'85 300SD 193k miles (parts)
'81 300SD 400k miles-sold
'84 300SD 205k miles-sold
'84 300TDT 270k miles-sold
'80 300CD 200k miles-sold

Linkage hitting the max stop?

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

You state that it performs properly above 2000 rpm with the turbo functioning.

However, is it actually performing to spec..........or is it simply performing better than it does below 2000 rpm? This is an important difference because if it's fine with the turbo, the IP timing and cam timing and fuel pressure and filters and every other thing related to making power are all normal.

If it's not making the specified power above 2000 rpm, then all of the aforementioned items become part of the possibilities.

I will tell you that your symptoms can be as stupid as a clogged tank screen or as serious as low compression............if the performance above 2000 rpm is inadequate.

A 0-60 time would be advantageous for attempting to determine a proper approach.

From what I've read so far...........the shotgun method has taken hold........once again.........with no requests for any data.

Gotta try the simple stuff first Brian

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

Update here after a week of having to take care of other stuff-


Did an acceleration test to establish a baseline. The 300SD in question posted the following results-

0-20 6 sec *12 sec when cold
0-40 12 sec
0-60 23 sec

I have another 300SD with 400k miles, a slipping transmission and blue smoke in the morning. It posted the following results-

0-20 4 sec
0-40 15 sec
0-60 30sec


Also, in the last week the Benz in question posted 27 mpg for a combination of freeway and city driving. And yes, I was careful in filling my tank.

So, this data confirms my initial observations that the SD in question has very low off the line performance. Once the turbo kicks in (about 2o mph) it takes off. Getting out of a driveway, up onto ramps, or up a hill in town is an arduous task for the car. Once it is moving it GOES!

I would like to look into the IP timing next but have not figured out how to access that bolt on the engine block side. Can anybody tell me their technique for accessing that bolt?

I'm reluctant to mess with the ALDA even though I found a thread where the exact same symptoms were solved by opening it up 1.5 turns (http://www.peachparts.com/shopforum/showthread.php?t=164111&highlight=low+rpm+power).


The linkage is hitting the max stop. I have adjusted the linkage, checked the cam timing, replaced fuel filters, pop tested the injectors and cleaned the lines to the ALDA & switchover valve as per my original posting. I have not done a compression check but it does not smoke and makes very good power once the rpms hit 2000 rpm. Also, it starts immediately in the morning when cold.



It is just LOW RPM power that is abnormal.


Thanks to eveybody who offers help!


rr

__________________
r2

'85 300SD 193k miles (parts)
'81 300SD 400k miles-sold
'84 300SD 205k miles-sold
'84 300TDT 270k miles-sold
'80 300CD 200k miles-sold

Did you clean the alda? Verify you are hitting max stop? Change fuel filters?

Those numbers are almost as slow as my stepdads auto 240.

The bolts on the IP are straight forward unless you have the rack limiter sensor (85, maybe 84 as well).

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

Unfortunately, your conclusion is not supported by the data. If we ignore the six seconds to get to 20 mph, we've got a time of 17 seconds to get from 20-60. This compares to a time of approx. 11 seconds for a properly tuned and operating vehicle.

Therefore, my suspicion is that the vehicle suffers from a malady that affects the entire rpm range. This would eliminate the turbo and boost from consideration and would direct your efforts toward low fuel pressure, improper IP and/or cam timing, improper linkage travel, or, in the worst scenario...........low compression.

Brian-

Where does your 20-60 mph time come from? Can you give me these acceleration specs and their source, please? thanks

__________________
r2

'85 300SD 193k miles (parts)
'81 300SD 400k miles-sold
'84 300SD 205k miles-sold
'84 300TDT 270k miles-sold
'80 300CD 200k miles-sold

A typical SD will run 14 seconds 0-60. I figure that three of those seconds are spent from 0-20. YMMV.

Brian- Where does "typical" come from? Factory specs or your experience? Either one is fine; I'd just like to know. You mention 11 seconds for 20-60 in a properly tuned and operating vehicle. Can you give me the source, as requested, of this spec? Realize here that I'm requesting data as per your original reply.

Does anybody else have acceleration specs?

Thank you.


rr

__________________
r2

'85 300SD 193k miles (parts)
'81 300SD 400k miles-sold
'84 300SD 205k miles-sold
'84 300TDT 270k miles-sold
'80 300CD 200k miles-sold

14 seconds for 0-60 is the factory spec..........give or take a fraction.

My SD will do 0-60 in 12.8 seconds.........so, it's not "typical".

"Typical" on the 0-20 time comes from experience. If the vehicle takes 14 seconds to go from 0-60, it won't take four seconds to go from 0-20. It also won't be able to do 0-20 in two seconds. So, three seconds is a reasonable estimation.

In any case, you're looking for specifications when you should be investigating the issues that I noted above.

Your symptoms are essentially identical to mine, and I'm 99.5437% sure my problem is a clogged tank screen. Sadly, I haven't been able to get a 22mm hex bit to clean the screen, and I always miss my window anyway due to having to drive the car so much (get low on fuel, hit my window, have to refill, miss window).

Anyway, clean your tank screen. If you can manage it better than I have

__________________
JBG
1985 TD wagon, 228k
running on grease since 3.07
AUSTIN, TEXAS

I don't have the specs but on my 300SD which still has some more fiddling to do on the engine I recorded just under 14 secons 0-60mph with a full fuel tank, all accessories present, and at least 100# of tools and parts in the trunk. This was using the car's speedometer. I have not compared the speedo to GPS yet to verify accuracy but from traffic around me it looks like it is close to accurate.

I have read the same specs on several threads with no disputes.