low performance/dangerously slow acceleration advice needed
 

since youall were so helpful with my last issue, i have another one that might be more up your alley!

the car is VERY slow, not just 60 some horsepower pushing a 3500 pound car slow, it is obviously something out of whack!

it only occurs when the engine is fully warm and when starting from a dead stop, rolling stops do not effect it.

what it does is the engine basically just idles, regardless to the accelerator pedal position. i have had to change my teavel routes so i can deal with it, but now i have a week off for summer break and want to fix it before classes begin again.

the engine runs like a top and, dare i say it, is quiet and smooth. it was purchased in january with 129k on it and i have since put 6k on it to total 135k. will a timing chain effect performance like this? im willing to bet that it hasnt been changed before. but maybe it has, all the filters on the engine were OE, someone cared for the car, but didnt leave the records in the vehicle. so let the thinking begin!

any help would be appreaciated and thanks in advance!

slow
 

have you looked at the fuel filters?

slow2
 

if the filters have black dots in them you have algae in the tank. if so go to a truck or tractor supply and get algaecide...use as instructed

nope
 

ive been through that, it was my first adventure with a broke ass down diesel!

i removed the tank, pressure washed it, soaked the screen in mineral spirits and cleaned it with a toothbrush. that cannot be the problem!

as far as dirty filters go, i just changed the pre filter(second time since ive had it) and assumed the big canister filter would be fine(3 small filters to one big one?)

Wrong assumption.

The canister filter, also known as the secondary filter, contains media that will provide the very fine filtering necessary to protect the IP. If this filter gets clogged, the engine won't rev. The pre-filter is there to stop any boulders from entering the secondary.

Change the secondary filter (large bolt on top) and report back.

algae
 

brian is right on re the large filter...also,


the algae can come from the pump. so even if you did all that, if you got a bad batch of fuel you could be all plugged up again. look for the black dots in the primary filter.

Very common for the linkage to have rubber bushings missing or other factors causing the linkage on injection pump to not reach the fully open position. Check it by having a friend prefferably a pretty girl press pedal to floor. Check if arm on injection pump is going to full travel by seeing if you can push it even further by hand at injection pump with engine off of course. If you have a genuine low milage car the timing chain etc are probably still good. Is your car a standard transmission model? Also what year. Wish I had one with about 130 k on it. :) Needless to say this is just a suplementary check that should be done anyways on these older diesels as what the others posts have stated is the most probable cause. If you have never changed the secondary filter especially. Also do you have a nice clean air filter? Diesels just seem to run better with them although I do not think by any stretch that the air filter is your problem. :)

i believe the mileage to be accurate
 

i am not sure about this, however. at some point the car was changed to have "exempt" o the mileage portion of the title.

this said, i believe it to be correct. the car is immaculate on the interior, but just torn up enough to make me believe that it is a 26yo 130k car.

pictures can be seen here: http://www.benzworld.org/forums/forums/thread-view.asp?tid=1209541&posts=17&hl=shlomo

let me know if you think i should reconsider thinking it has only 135k on it!

**edit**
I got the crankcase cleaner(internal kind) and two gallons of fresh rotella t tonight along with the two fuel filters and an oil filter, i will spend the day with it and do that and then report back, my dad said that he would help me set the valves this week as well, but i cant do that after changing the oil=) so itll have to be the day after tomorrow(unless catastrophic geological events prevent it)

knowing the actual total milage on a car is not all that important. You probably have one of the best type of cars for your age group. One of the good things is that you can cope with a lot of things on this car plus parts are pretty reasonable when and if you need them. You may encounter a few problems but they will strengthen your self confidence as you deal with them. That is an extremely valuable benifit. The problems will not seem that minor to you the first time around but the expression that anything worth learning has to have some difficulty is perhaps true. You are obviously learning already and with a site like mercedesshop how can you really go wrong? Before you know it you will be helping others out. I already see you are projecting a little differently. Remember also to develop judgement when reading helpful suggestions. What I say is just my opinion and should be taKen that way. I too like your car and try to treat it like a classic as they will never make cars like these again and that is truly too bad. :sun_smile

total tune-up did not help
 

the engine does run smoother/quieter but it still doesnt perform like i think it should!

let me drive it some more and i'll let you know how its doing. just, after spending the 40 some dollars to do everything now im short on gas money hahaha

such is life, huh?

Clogged fuel filters would more likely affect high speeds,

Poor acceleration from stop is very likely to be cured with an ALDA adjustment to richen the fuel mixture. Every one of my cars has needed it and wow, does it make a big difference.

Do a search here to find out how. It's VERY satisfying and easy. You should be able to throw gravel from a start on a dirt/gravel road.

While you're setting the valves, check your timing chain stretch by lining up the mark on the rear of the timing gear with the notch in the cam support. It's on the drivers side rear of the timing gear. With this lined up very carefully, you will have a reasonably good idea if your chain is stretched more than 2 degrees. I think performance is seriously affected around 4 degrees measured at the crank.

And checking your throttle linkage to make sure the arm on the IP is up against the stop when the pedal is fully depressed is a good idea too.

Best Wishes,
Bruce McCreary
(2) '85 300Ds, '83 300CD

i should have been more clear! i dont have a turbo, it is a 240D 2.4!

Read your first post.

It's 67 hp pushing a 3300 lb. car.

How fast do you expect it to be?

Most folks run out of pavement before they can do a proper 0-60 time. :(

I am sure leathermang will smack me but the car sould be peppy. My 240D, through the gears, will do just dandy around town. I presume you have checked for dragging brakes and the like? I would have a look at the ALDA adjustment if everything rolls nice and easy. The ALDA on my 240D has been tweaked with so my car gets movin pretty good. The 300SD likes it too but that is a whole seperate 100+ HP discussion ;)

How do you like it otherwise? Handle good? Where are you located?

I tell you, what made the biggest difference in acceleration on my 240D was replacing the injectors...just a thought...like night and day.

Brian makes a good point. Time your 0-60 in a safe manner and either put it on the site for comment or have a look in the archives. Then you have a known baseline. Suspect yours may be a little slow though as you quote you have to pre-engineer your travel. But then again I am even a little cautious in certain situations as well with my 240d. :D

I suggest you consider these two tread - well okay "threads" - which I just happened to have started:

The first has to do with the in tank filter.

http://www.peachparts.com/shopforum/showthread.php?t=124027

The second has to do with the replacement of a leaky primer pump, which allows air to get in with the fuel. I had a similar loss of power as you have described.

http://www.peachparts.com/shopforum/showthread.php?t=109076

the car is fabulous! its roomy, heavy, loud and stinky. everything my vws werent.

it does ok on the big hills here in dixie(alabam') but only on the interstate. the maintenence helped smooth the car out a great deal, and i ran motor flush through it just to see if it would ungunk anything. seems like it did something, but that might just be my imagination. at one time i would have sworn my neon ran better when it had a fresh coat of wax on it!

i do enjoy the car. a great deal, its just very sturdy. i like how bumps dont make the entire dash jiggle and squeak like a cheap pair of shoes.

eventhough i like it as much as i do, it cant be ignored that i am a college student that commutes 80 miles a day. i need it to be reliable. it hasnt been unreliable, per se. just has needed constant "tweaking" which is a blessing and a curse

i like that the car is well built enough that you can turn screws and fix things, pop fasteners suck ass. but i also dont like that you HAVE to turn these screws to fix things every weekend!

oh yeah-- the car is still doing it, ill get my mom to push the throttle and see if the linkage is weird, ill also grease all the connections when im under there.

what is the alda adjustment? i thought that was a turbo thing?

Even the non turbos have an "altitude device" that can be adjusted to give you more fuel. Though I am out of my league on this one...see if anyone else picks up what this specific model has.

ohh, no more fuel, it only gets about 24mpg! i was told(before i purchased it, of course) that these cars would get nearly comparable mileage to that of my neon. its never really happened.

as an aside, could too much fuel bog down the engine like this?

Unless its streaming out the fuel pipe...no.

Also...ALDA adjustments on my 300SD increased my MPG becuase I got up to speed quicker and let out of the throttle quicker.
WHen you keep having to mash your foot into it, you are using more fuel than if you quickly got up to speed with the slight increased fuel rate.

Your car could be starting off in 2nd gear. Mine did. Transmission flush and filter helped.

____________________________________

83 300sd
3 fords

the kickdown works on this car. sometimes, it feels as though second gear is stronger than first!

you can push the button under the pedal and then just wait and hold up traffic and hear people honk and flash their lights.

it really does take from 5-7 seconds to start going, and all it does in that time is crawl with the engine idling.

this doesnt always happen, though! and it is usually when the car is warm, as opposed to cold.

sometimes i feel as though the car gets "tired" thats the only way i can describe it really. it runs great, but wont roll. it shifts fine i wouldnt think its a transmission problem, but ive been wrong before! would the torque converter be slipping that badly? my dads ram truck just needed one and to think about it, it did sort of show the same symptoms! wouldnt it do it alot more if it were the torque convertor? i know when i ran it out of gas the first day i had it(the tank screen was plugged and the gauge sender was full of yuck too so it registered 1/4 tank at empty) it exhibited the same symptoms of an air cooled vw burning a valve and dying a quiet death. heh heh

ill eagerly be awaiting youalls torque converter stories. i greased the linkages and that didnt help, btw

If the torque converter was slipping, the engine would rev way up to redline and the vehicle won't go anywhere.

In your case, the engine won't rev and the vehicle won't move, so it's not the torque converter, or the transmission.

The engine is not getting fuel for some reason.

Did changing of the filters help the situation, even temporarily? Did the symptom go away for a bit and then return?

not at all, its the same with new filters as it was before.

it works fine for a while till its been driven to full operating temperature and thats when the problem is.

Have the valve adjustments been checked? I never saw a single comment about that in the thread as its only when it is up to emp and not cold.

nosir, the valves have not been set.

i do not know enough to do that myself, nor do i have the tools to do it with. my dad said he would help me set them sometime, i guess i could just pull it halfway into the garage and have the valve cover off when he gets home today(in 2 hours)

heres a question: we're in the south and our driveway is a hill, i have to start the car to get it in the garage enough for water(its going to be raining for the next week) to not get into the open engine, will running it for like 30 seconds and pulling it into the garage impact valve adjustments?

i know on the vw it was always said to do them completly cold(not that i ever did those, either...they always died before i had the chance!)is that cold enough?

30 seconds won't matter....the key is the motor is at ambient temps.....

you may find you have tight valves when cold and its holding valves partly open when hot killing power....if not...you will have a baseline as to when it was done and what its adjusted to. Nothing lost...

Move the car and let it sit 15-30 minutes what heat was generated will dispersethroughout the motor and basicly still be at ambient temp...

You are wasting your time, buy a fuel pump
 

Your fuel pump is dead. I would bet anyone here. Its not valves, its not filters, when the pumps go, they go and thats all there is to it.
When you replace it, stick oil in the tank (like 3 oz) each time and you will get 300K from the next one....

So, this is a defective fuel pump that is affected by engine temperature??
When cold it pumps just fine, and then when warm, it won't maintain fuel pressure?? :confused:

Fuel pumps basicly work or they don't.......valve clearances do close up when hot...and on a tight valve when cold will hang open when hot....when he checks his valves we will see who is right.....IP's CAN fail but rarely do except when alternative fuel experiments are done by people who do not properly research before they hose their car up....

I'll chime in here:

Things to check first -- valve adjustment (not expensive, but it HAS to be done), condition of hand pump (if it's the screw down type, replace it with the sealed type), suction side hoses, and fuel screen in the tank.

The key is that it slows way down warm -- ie, after it's been running a while. You cannot really clean the screen, replace it. If the problem is worse with a low tank, for sure it's algae. Pressure washer may not cure the problem, you need algicide (marine supply stores have it, if not use a bottle of Redline, the whole thing in one tank), and change filters again.

If the power loss happens only with a hot engine (after running a while) it has to be valves going open, tranny stuck in 2nd (or third!), or a fuel restriction.

Try holding the kickdown switch down until you have to let up to avoid the car in front (hehe!) and see if it's shifting properly. It should, I think, sit in 2nd gear and downshift immediately into first when you press down on the pedal. You can test this by starting off in 2 -- it will start in first and upshift to 2nd that way. If you get normal performance, it's the downshift adjustment or the tranny modulator -- most likely the modulator at this point.

You should also check the chain for stretch and injection timing as well, although you won't get horrible performance if they are off.

0-60 times are around 19-20 sec, not horrible, just watch what you pull out in front of.....

Peter