Plan of attack on the E300 (fuel starvation and ping type rattle) - PeachParts Mercedes-Benz Forum

TylerH860 · #1 01-12-2011, 05:48 PM

I've decieded to make this a dedicated thread to aid those in the future and to also perhaps attract fresh folks who didn't see the problem in Jimmy's old 6+ page long thread on the 1995 E300. Note this is the same motor for 96-97 E300 diesels.

Problem:
When tempuratures get below 45* the car displays the classic symptoms of fuel starvation. Startup and idling is effortless and quiet, along with getting off the line from about 0-30 MPH. Once it hits the rev range of about 2500, a rattle noise (sounds like dieseling and pinging together, certainly not valves) starts in and gets nasty, bogging down the car. If I am light on the pedal then I can get a steady acceleration to 70, but if I floor it the car will stumble and struggle to 40. There is only a slight improvement from a cold engine to a warm engine, which I suspect is just the natural way these cars are based on most of the others I've had.

If the temperature is above 45* this problem is nearly non-existent. Only at the highest rev ranges of a WOT do you start to here the rattle (faintly) and a very slight cut out before the shift.

The effortless cold start and smooth idle and launch eliminates glow plugs (which were recently tested), compression, top end, and injectors, in my opinion. Recently the heat exchanger was replaced along with the primary fuel filter and a leaking fuel line. This was shortly before me purchasing it.

So far we have 4 theories:

1: The secondary fuel filter has not been changed. Cold fuel is thicker thus harder to pass through the clogging fuel filter. While it seems strange that it would only be showing ill effects in the cold this is always the first step in diagnosing a fuel starvation problem. It does not explain the rattle, as in the past I have not heard this noise when I had bad fuel filters. Also, fuel filter problems are usually more rapidly degenerated and this problem has been consistent for 2 winters now.

2: Failing lift pump. Colder fuel is thicker and harder to send to the IP. This also seems odd since due to the temperature change and rattling. Also, the issue seems unaffected by hills. Whether I enter an uphill on-ramp or downhill on-ramp the problem remains consistent.

3: Air is getting into the system via leaky fuel line or delivery valve o rings. Once again, this does not explain the temperature variation and rattling. There is also no visible leaks or a fuel smell associated with this issue. Colder air would be more dense and harder to get through a leaking fuel line.

4: Injection pump timing is off. Over the years a timing chain stretches and slowly takes the injection pump out of sync with the engine. The rattle is a classic symptom of retarded injector timing. With the colder being more dense and oxygen rich, it exacerbates the issue with the injector pump timing. While diesels don't have the electronic compensation that modern gassers and later diesels have, could cold air make that much of a difference?

I believe number 4 is the most likely scenario, but it could also be a combo of number 4 and anything.

Any other ideas?

colincoon · #2 01-12-2011, 09:13 PM

I would try fuel lines first and go from there. I'm not to familiar with the newer diesels but if the fuel lines are rubber then there is a good chance they are expanding and contacting with the ambient temperature. If there its a hairline crack then air could be getting in.

But I'm most likely wrong.

TylerH860 · #3 01-12-2011, 11:21 PM

Quote:

Originally Posted by colincoon

I would try fuel lines first and go from there. I'm not to familiar with the newer diesels but if the fuel lines are rubber then there is a good chance they are expanding and contacting with the ambient temperature. If there its a hairline crack then air could be getting in.

But I'm most likely wrong.

No, its a good idea. The issue is once the engine is up to temperature and running for a while that fuel line would be warmer and the car's condition would improve. This does not.

Doing an overhaul of all the rubber on the IP and related lines then doing a calibration would be a good idea, but I don't think I'll go that far now.

tankowner · #4 01-13-2011, 12:01 AM

Quote:

Originally Posted by TylerH860

I believe number 4 is the most likely scenario, but it could also be a combo of number 4 and anything.

Any other ideas?

Tyler,

I believe my '95 exhibits the same or similar symptoms to what you are describing, but having become accustomed to them, I should probably evaluate again. Nevertheless, I am going to say that, as of now, I think #4 may be the most likely of the choices you have listed. Over the past couple years, I have address all of the first three and don't recall any real change in the rattle. I'm not sure I would say my symptoms are classic fuel starvation . .. but the rattling is there and some bogging down that seems to be alleviated as the engine warms. I have always attributed this to worn injectors . . . and hadn't really considered the timing being off. I don't recall, did Jimmy ever rebuild the injectors on this one? I'll try to keep an eye on this and see what mine is doing these days.

TylerH860 · #5 01-13-2011, 12:11 AM

Quote:

Originally Posted by tankowner

Tyler,

I believe my '95 exhibits the same or similar symptoms to what you are describing, but having become accustomed to them, I should probably evaluate again. Nevertheless, I am going to say that, as of now, I think #4 may be the most likely of the choices you have listed. Over the past couple years, I have address all of the first three and don't recall any real change in the rattle. I'm not sure I would say my symptoms are classic fuel starvation . .. but the rattling is there and some bogging down that seems to be alleviated as the engine warms. I have always attributed this to worn injectors . . . and hadn't really considered the timing being off. I don't recall, did Jimmy ever rebuild the injectors on this one? I'll try to keep an eye on this and see what mine is doing these days.

Yes, but the difference is cold and warm engine tempurature does not matter with mine, just exterior temperature. I drive the car all day long and the situation does not improve unless it gets warmer outside. Yours does sound like injectors. How does it idle when cold? The rattling noise may be because of the IP timing but its not bad enough to be effecting performance like mine. Of course, I'm spitballing at this point.

JimmyL · #6 01-13-2011, 12:55 AM

One more thing of note: When it is cold and you are trying to build up speed, the farther down you push the pedal, and the higher the rpm's go, the more it bogs/rattles/pings/cuts out. The lower the rpms, the better chance I used to have of climbing a hill near the house. If I buried the pedal trying to climb the hill, the car would severely cut out, and would even trail pretty thick lighter colored smoke. But you really had to be raising the rpm's. Hence my belief that it was an injector issue. Just dumping the cold fuel instead of a nice spray. {and don't ask what color. I can see two smoke colors: black and light. Blue, white? No idea.....} This is "not black".

If I kept the rpms low I could climb the hill moderately in higher gears and keep on going. It is consistent enough to "learn" how to get around the issue. But the actions of the car are always consistent with temperature.
As Tyler says, it starts instantly and idles smoothly.
A small observation about starting; once the afterglow function turns off, the idle gets just a bit smoother. Every time.
Those are my cold weather memories. It is very happy when it's 105!!!!

TylerH860 · #7 01-13-2011, 01:20 AM

Quote:

Originally Posted by JimmyL

One more thing of note: When it is cold and you are trying to build up speed, the farther down you push the pedal, and the higher the rpm's go, the more it bogs/rattles/pings/cuts out. The lower the rpms, the better chance I used to have of climbing a hill near the house. If I buried the pedal trying to climb the hill, the car would severely cut out, and would even trail pretty thick lighter colored smoke. But you really had to be raising the rpm's. Hence my belief that it was an injector issue. Just dumping the cold fuel instead of a nice spray. {and don't ask what color. I can see two smoke colors: black and light. Blue, white? No idea.....} This is "not black".

If I kept the rpms low I could climb the hill moderately in higher gears and keep on going. It is consistent enough to "learn" how to get around the issue. But the actions of the car are always consistent with temperature.
As Tyler says, it starts instantly and idles smoothly.
A small observation about starting; once the afterglow function turns off, the idle gets just a bit smoother. Every time.
Those are my cold weather memories. It is very happy when it's 105!!!!

Lightbulb.

How about I park the car in my shop with the heat cranked to max all day? If the car is improved and drives great out in the cold then we know its from cold fuel, not cold air.

Skid Row Joe · #8 01-13-2011, 01:37 AM

That'll work. . . .

Diesel911 · #9 01-13-2011, 11:34 AM

Quote:

Originally Posted by TylerH860

I've decieded to make this a dedicated thread to aid those in the future and to also perhaps attract fresh folks who didn't see the problem in Jimmy's old 6+ page long thread on the 1995 E300. Note this is the same motor for 96-97 E300 diesels.

Problem:
When tempuratures get below 45* the car displays the classic symptoms of fuel starvation. Startup and idling is effortless and quiet, along with getting off the line from about 0-30 MPH. Once it hits the rev range of about 2500, a rattle noise (sounds like dieseling and pinging together, certainly not valves) starts in and gets nasty, bogging down the car. If I am light on the pedal then I can get a steady acceleration to 70, but if I floor it the car will stumble and struggle to 40. There is only a slight improvement from a cold engine to a warm engine, which I suspect is just the natural way these cars are based on most of the others I've had.

If the temperature is above 45* this problem is nearly non-existent. Only at the highest rev ranges of a WOT do you start to here the rattle (faintly) and a very slight cut out before the shift.

The effortless cold start and smooth idle and launch eliminates glow plugs (which were recently tested), compression, top end, and injectors, in my opinion. Recently the heat exchanger was replaced along with the primary fuel filter and a leaking fuel line. This was shortly before me purchasing it.

So far we have 4 theories:

1: The secondary fuel filter has not been changed. Cold fuel is thicker thus harder to pass through the clogging fuel filter. While it seems strange that it would only be showing ill effects in the cold this is always the first step in diagnosing a fuel starvation problem. It does not explain the rattle, as in the past I have not heard this noise when I had bad fuel filters. Also, fuel filter problems are usually more rapidly degenerated and this problem has been consistent for 2 winters now.

2: Failing lift pump. Colder fuel is thicker and harder to send to the IP. This also seems odd since due to the temperature change and rattling. Also, the issue seems unaffected by hills. Whether I enter an uphill on-ramp or downhill on-ramp the problem remains consistent.

3: Air is getting into the system via leaky fuel line or delivery valve o rings. Once again, this does not explain the temperature variation and rattling. There is also no visible leaks or a fuel smell associated with this issue. Colder air would be more dense and harder to get through a leaking fuel line.

4: Injection pump timing is off. Over the years a timing chain stretches and slowly takes the injection pump out of sync with the engine. The rattle is a classic symptom of retarded injector timing. With the colder being more dense and oxygen rich, it exacerbates the issue with the injector pump timing. While diesels don't have the electronic compensation that modern gassers and later diesels have, could cold air make that much of a difference?

I believe number 4 is the most likely scenario, but it could also be a combo of number 4 and anything.

Any other ideas?

1- Change the Secondary Filter if only to elimnate it as a cause.
2- The Lift Pump Rebuild kit is 40 something. Up hill verses down Hill effects pressure; but would not effect the Volume as much. If a Valve in the Lift Pump was not seating well some of the Fuel would just be going back and forth.
3- I do not know if thicker Cold Air would not pass through a Crack if there is a Vacuum on the other side.
In the Cold the O-ring material would contract and may be the source of an Air leak. Do solids contract more than Gasses in cold temps?
4- Late Timing combined could cause the issue you speak of and worn Injectors would add to the problem.
There is not enough difference in the Air density to have an effect. The knocking is due to the bulk Fuel burning at the wrong time and place in the Precombustion chamber. Meaning it is not getting exposed to the O2 when it is supposed.

Since the problem has to do with when you step hard on the Pedal and temp related this makes me guess it might be something going on with the EGR System. (The EGRs seem to also be controld be a Temp Sensor/s some where. If one of the Sensors is the temp of the Intake Air that could be part of the reason for ratteling during cold ouside temps even though the Engine is warm.)
Too much exhaust gas is being mixed with the Intake Air when you are tromping on the Pedal.
I think this would cause a late burning of the Fuel and that knock.

johninva · #10 01-13-2011, 12:42 PM

Quote:

Originally Posted by Diesel911

Since the problem has to do with when you step hard on the Pedal and temp related this makes me guess it might be something going on with the EGR System. (The EGRs seem to also be controld be a Temp Sensor/s some where. If one of the Sensors is the temp of the Intake Air that could be part of the reason for ratteling during cold ouside temps even though the Engine is warm.)
Too much exhaust gas is being mixed with the Intake Air when you are tromping on the Pedal.
I think this would cause a late burning of the Fuel and that knock.

i think this car has egr bypassed somehow or another. But i was thinking along sort of the same lines - maybe some issue with the resonance flap system in the crossover or the intake manifold

whunter · #11 01-13-2011, 01:36 PM

Quote:

Originally Posted by TylerH860

I've decieded to make this a dedicated thread to aid those in the future and to also perhaps attract fresh folks who didn't see the problem in Jimmy's old 6+ page long thread on the 1995 E300. Note this is the same motor for 96-97 E300 diesels.

Problem:
When tempuratures get below 45* the car displays the classic symptoms of fuel starvation. Startup and idling is effortless and quiet, along with getting off the line from about 0-30 MPH. Once it hits the rev range of about 2500, a rattle noise (sounds like dieseling and pinging together, certainly not valves) starts in and gets nasty, bogging down the car. If I am light on the pedal then I can get a steady acceleration to 70, but if I floor it the car will stumble and struggle to 40. There is only a slight improvement from a cold engine to a warm engine, which I suspect is just the natural way these cars are based on most of the others I've had.

If the temperature is above 45* this problem is nearly non-existent. Only at the highest rev ranges of a WOT do you start to here the rattle (faintly) and a very slight cut out before the shift.

The effortless cold start and smooth idle and launch eliminates glow plugs (which were recently tested), compression, top end, and injectors, in my opinion. Recently the heat exchanger was replaced along with the primary fuel filter and a leaking fuel line. This was shortly before me purchasing it.

So far we have 4 theories:

1: The secondary fuel filter has not been changed. Cold fuel is thicker thus harder to pass through the clogging fuel filter. While it seems strange that it would only be showing ill effects in the cold this is always the first step in diagnosing a fuel starvation problem. It does not explain the rattle, as in the past I have not heard this noise when I had bad fuel filters. Also, fuel filter problems are usually more rapidly degenerated and this problem has been consistent for 2 winters now.

2: Failing lift pump. Colder fuel is thicker and harder to send to the IP. This also seems odd since due to the temperature change and rattling. Also, the issue seems unaffected by hills. Whether I enter an uphill on-ramp or downhill on-ramp the problem remains consistent.

3: Air is getting into the system via leaky fuel line or delivery valve o rings. Once again, this does not explain the temperature variation and rattling. There is also no visible leaks or a fuel smell associated with this issue. Colder air would be more dense and harder to get through a leaking fuel line.

4: Injection pump timing is off. Over the years a timing chain stretches and slowly takes the injection pump out of sync with the engine. The rattle is a classic symptom of retarded injector timing. With the colder being more dense and oxygen rich, it exacerbates the issue with the injector pump timing. While diesels don't have the electronic compensation that modern gassers and later diesels have, could cold air make that much of a difference?

I believe number 4 is the most likely scenario, but it could also be a combo of number 4 and anything.

Any other ideas?

The fuel pre-filter +O-ring is always first on the list for your engine.

Look here for other common issues.

OM606.912, 1996-97 E300 Turbo Diesel Plastic injection pump lines
http://www.peachparts.com/shopforum/showthread.php?t=193833

.

Skid Row Joe · #12 01-13-2011, 01:55 PM

Quote:

Originally Posted by TylerH860

3: There is also no visible leaks or a fuel smell associated with this issue.

Note!

pawoSD · #13 01-13-2011, 02:43 PM

Seems highly unusual that "cold fuel" would cause those issues....if the fuel is not gelled...which is highly unlikely, then there should not be much difference to the engine. I would think its an injector issue or fuel filter/air sucking issue. Under heavy throttle its trying to inject more fuel, and if it cannot get that fuel, its going to bog down/nail/have issues.

With under 200k on a 606 I would not think the timing chain would have stretched enough to mess up timing that much. It also makes no sense as the issue is only outside temp related, engine temp would have more to do with that if it were the problem. When my 617 had a really stretched chain, it was harder to start, and had less power....thats about it....never bogged down or anything, and cold/hot made not much difference aside from starting. My chain was at NINE degrees stretch at that point.

New chain led to more power and quicker starts.

TylerH860 · #14 01-13-2011, 03:17 PM

Quote:

Originally Posted by pawoSD

It also makes no sense as the issue is only outside temp related, engine temp would have more to do with that if it were the problem.

No, it makes absolutely no sense, but that is the case. Engine operating tempature has little to do with this symptom. If its 30 degrees outside I could drive the car all day long with my errands and it doesn't improve. 50+ degrees and its barely a problem.

The prefilter was changed when first trying to understand this issue. O-ring... who knows. It makes no sense that its the secondary fuel filter, and the effort to do this without a primer pump seems futile.

TylerH860 · #15 01-13-2011, 03:28 PM

Right now I have the car parked in my shop with the thermostat set at 80, and a reptile cage stick on space heater fuel tank. This evening after dinner I will go take the car out and drive it. If it does awesome, then I've eliminated outside air being too cold (as crazy as it sounds) as an issue.

This just doesn't make sense, and that's why it makes me mad. With the engine warmed up it shouldn't be effecting it.

Having a crossover pipe that has to be removed just to examine all this stuff is very agitating as well. You can't do a little thing without going through the whole process.

I was really looking forward to having one of these, and I'm trying to not let this problem get to me too much.