83 300SD Turbo painfull acceleration - PeachParts Mercedes-Benz Forum

R Leo · #1 12-09-2003, 11:36 AM

I'll give you $75 for it.

#2 12-09-2003, 11:40 AM

Hi Cabazon.

Replace the fuelfilters.

Have the valves adjusted if you don't know
when they where done last.

Clean the banjo fitting on the back of the
intake manifold,also check the lines going
to the ALDA for any oil/carbon build up.

Please feel free to chime in.

Louis.

bodyart27 · #3 12-09-2003, 11:43 AM

Maybe run a couple of cans of diesel purge through the system - if anything it will run smoother.

Check the air flow -> filter condition, check for blockage in the u-bend going from the air assembly to the turbo. I remember someone leaving a rag in there once.... doh! With the u-bend off, does the turbo spin freely?

I found the biggest performance kick from doing a valve adjustment on my 83SD (184K mi)- like night and day off the line. Almost all the clearances were too tight (engine was not breathing well). If you have the tools and the knowledge - it's almost a zero cost thing to do ($ new gasket). If you have the service records it is something to check if it has been done. It is recommended 15K miles, but you can go longer.

rickg · #4 12-09-2003, 11:45 AM

Just curious. What's the elevation where you live? My SD is a real dog at higher elevations, just as you describe, but fine near sea level, and it has fresh engine, IP, ect. Maybe your new car just doesn't like high elevations. I'm still learning about what can be done about this. From what I've seen guys here talk about, it's the ALDA adjustment.

#5 12-09-2003, 12:33 PM

I have a 1980 300SD turbo 365,000KM and have recently acquired a 1983 300SD turbo. I made a big mistake and didn't drive the car before I bought it, as a friend had checked it out for me.
The car is in near mint condition with 200,000KM. It has a serious problem with engine performance especially at low speeds. It is totally gutless, ie no acceleration off the line until the turbo cuts in. If you are travelling in town at say 40km/hr and push on the throttle nothing happens unless you push it through the floor.
The 1980 has way better acceleration between lower gear changes and responds quickly when you push down on the throttle at any speed. The 83 will go great at high speeds on the freeway but is a dog in city traffic. You have to push the accelerator to the floor to get moving. It seems to have no acceleration until the turbo cuts in

I have been to and talked to 3 local shops and spent money to get only advice and no resolve. Some say I need a transmission rebuild others say, IP problems others say valve ajustments and timing chain. Others say fuel problems. I can see myself getting empty pockets fast to fix both IP and tranny .
I changed all filters with no improvement. It seems to go fine once the turbo cuts in but it accelerates painfully slowly before the turbo cuts and seems the worst trying to speed up from around 40K/Hr.
Lack of fuel doesn't make sense, as I can fly on the freeway and maintain high speed on hills on cruise control. I do believe that the transmission could need rebuilding but I don't know if that can be a key to the power problem. Another possible clue is that, it will hardly move at all if you try to drive out of the yard without warming the car up for a few minutes.
Other things which may be of importance is, that it starts instantly and runs smoothly in freezing conditions. There are no fuel leaks anywhere, and the engine compartment is spotless
I would much appreciate any suggestions on where to go with this.

lietuviai · #6 12-09-2003, 06:22 PM

Quote:

Originally posted by R Leo
I'll give you $75 for it.

I'll bid $76!

lietuviai · #7 12-09-2003, 07:54 PM

Aren't the W116's smaller and lighter than the W126's?

lietuviai · #8 12-09-2003, 08:22 PM

Quote:

Originally posted by 300SDLLLL
I don't think so. If anything I would say the W116 is a heavier car. The W116 cars don't have an EGR valve though.

A KBB I just looked at now from 1985 puts the 83 300SD at 3680 LBS with a WB of 115.6" and the 80 at 3605 with a WB of 110". Not really a big difference. They both have 120HP. Maybe the 80 is geared better. It looks like the W116 turbo diesel would be more in the same league as a W123 turbo diesel since they have the same WB and nearly the same weight.
The EGR is an easy thing to take care of.

#9 12-10-2003, 10:35 AM

Thanks Louis for the suggestion sRe:banjo fittings Now I just have to learn What and where the ERG valve is, and how to deal with that. Also same what and where about ALDA adjustment mentioned.
I suspected that there could simply be differences between years as TXBill suggests. I have already replaced all filters and I am at sea level on Vancouver Island. Can't go to Rockies as our Ferries are strike bound. Thanks for feedback. You guys all make for a great forum.
Rick

BobK · #10 12-10-2003, 12:07 PM

Maybe a dumb question, but is your car starting out in first gear? Ever? I have seen the wire to the kick down solenoid on the transmission go bad and you start out in second no matter what you do. This can be even slower than normal. If your 126 car has the position for first gear (put in second then move stick to right), put it in that position, start out and then snap it over to the 2nd gear postion at about 15 mph. If the transmission does not shift up, you already were in second. My wife's 107 has that problem right now and I just have to find the time to put the car up on ramps and find the bad wire.

gsxr · #11 12-10-2003, 04:42 PM

Cabazon,

1- Edit your profile preferences with your proper time zone, so your posts don't appear out of order

2- If power is good "once the turbo kicks in", you don't have problems with the filters - forget that

3- Low power off idle is almost always low fuel delivery off idle. This can usually be adjusted with the ALDA. Search this forum, it has been discussed a billion times, we're not going to spell it all out AGAIN.

4- Ditto for the EGR valve - use the "search" button at the top right of the page

5- If you live at high elevation, well, you're gonna have to live with some power loss. Below about 3000ft it should be pretty quick. Find a flat road and time the car - with a STOPWATCH - from 0-100kmh. It should be about 15 seconds or so. If you're at 20+, then yeah you have problems. Do the ALDA first, that's my top choice as a solution to your problem.

HTH,

#12 12-11-2003, 12:31 PM

I May be missing something here but I can,t seem to see any place to enter time zone. Any way Courtenay BC Canada is at sea level and in the pacific time zone.
What may be the problem is that I have a new computer and when the power goes out here, which has been often due to recent storms, my computer defauls back to Jan1 12:00am 2001 and I dont notice the change I will change it back to the right time and see if that helps.

I will look up the ALDA thing
Re; post about testing for first gear there is no right or left slots in the 2 position and it does start in first gear. It does shift from 2nd to 3rd very quickly ie spending only about a second in 2nd gear. This may be a normal thing though.

I finally contacted a reputable Mercedes repair depot in Langley who emphasized that this car should not have any less power than the 80. He suggests that a valve adjustment is the first step. The slow acceleration at low speeds he claimed is a injection timing problem . He will reclock the timing pump which can be be moved 1 or 2 steps without taking out the pump. Further reclocking requires removal of the pump which will be more costlybut reasonable . Does this make sense?

gsxr · #13 12-11-2003, 12:43 PM

1- Edit the time zone by clicking the "user cp" button at the top right, then selecting "Edit Options", and the time zone selection is near the bottom. I thought it defaulted to PST but perhaps not - hmmm. Not sure if your PC clock has anything to do with it.

2- The car should not shift from 2-3 very quickly at full throttle. If so, something is wrong with the Bowden cable. They do tend to do this at light throttle, which I find annoying, so I shift manually most of the time - pull the lever back to 2 and only move it to 3 when I *want* the tranny to shift to 3rd gear.

3- Your reputable MB repair depot is only half right. Yes, a valve adjustment can make a huge power difference if your valves are way out (adjustment needed every 15kmi, or about 22kkm). The slow acceleration has nothing to do with pump *timing*. If the injection pump timing is off, that means the timing chain is stretched. A new chain fixes the pump timing. Adjusting the timing (and using an offset key to correct cam timing) may help power *slightly*, and may improve MPG, but won't make the car any faster off the line. You need to increase the fuel delivery (richer mixture) off idle, which is done by fiddling with the ALDA. Removing the pump to "re-clock" it is only required if the pump was not installed correctly in the first place, and the timing is way, WAY off! He doesn't know what he's talking about, IMO. I wouldn't let that guy touch the pump, and I'd have reservations about letting him do the valve adjustment too.

Link to an MB document with ALDA adjust info (turn 1.0 turns CCW though, not 0.25).
http://www.meimann.com/docs/mercedes/Bosch_ALDA_adjust.pdf