|
|
|
#46
|
|||
|
|||
So you have a turbo engine.............have you modified the alda(on the injection pump) or turbo boost?
Those temps aren't abnormal like many others have said. Don't sit on long hills on full throttle, just a bit below. that gives you excess air v. fuel which helps keep your engine temps down. Also check that you are running the full spec boost since underboosting will actually increase engine temp due to the lower amount of cool air entering the engine and because you will use more "throttle" to get the same power.
__________________
Alex. MB Tech Sydney, Australia Volvo 122S W201 190D 2.5 manual W202 C240 W203 C32 |
#47
|
|||
|
|||
Quote:
If you give it more "throttle", nothing happens. If it is underboosted, no more air is fed to the engine and therefore no more fuel is fed to the engine. |
#48
|
||||
|
||||
Quote:
There are no other screws to remove. There are 3 bolts that fasten the fan blade to the clutch but you don't mess with those unless you are replacing the clutch with a new one, that does not include the fan blade. The fan shroud must be centered (as best possible) and there is a range of adjustment on the shroud locating tabs. The new fan should not touch anything or reduce clearance on anything. If it comes too close to the shroud, or radiator, you may have a bent radiator support from hitting a curb or something (VERY common on the 1987 W124 diesel). A simple test is the lower sound panel - do the holes in the panel line up properly with the holes in the body? Usually the body holes will be 1/2" to 1" closer together because the support has been knocked inward, reducing fan clearance. More than one radiator has been destroyed this way (under hard braking, the engine moves forward just enough for the blades to rip into the radiator!). Vac pump - that is to prime and/or lube the new pump. I've done this 3 times with no problems. Remember to remove the metal basket if you use the "dam" gasket or you'll have to do the job over again to fix the massive oil leak. |
#49
|
||||
|
||||
Quote:
|
#50
|
|||
|
|||
Quote:
__________________
Own: 1986 Euro 190E 2.3-16 (291,000 miles), 1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000, 1988 300E 5-speed 252,000 miles, 1983 240D 4-speed, purchased w/136,000, now with 222,000 miles. 2009 ML320CDI Bluetec, 89,000 miles Owned: 1971 220D (250,000 miles plus, sold to father-in-law), 1975 240D (245,000 miles - died of body rot), 1991 350SD (176,560 miles, weakest Benz I have owned), 1999 C230 Sport (45,400 miles), 1982 240D (321,000 miles, put to sleep) |
#51
|
|||
|
|||
Quote:
This is the fundamental question. Let say, for argument, that I am running 10 psi boost at 3000 rpm in fourth gear travelling upgrade at 70 mph in the SDL. The pedal is not floored but the engine is working pretty hard. No visible smoke, however. The engine is presumably still getting more air then it needs. Now, I plant my foot into the throttle. The boost climbs to 11 psi. The question is whether the IP knows that I am now at full throttle and enriches the mixture beyond what would normally be required for 11 psi boost ? If it does this, I would like to know the mechanism on the 603. I can tell you that it is not apparent because there is no additional smoke when the pedal is floored. If it kicks down to third, however, and the rpm's climb, the volume of air and fuel is significantly increased and there will be some smoke, but not the heavy black smoke that is characteristic of an overfueled condition. |
#52
|
|||
|
|||
On my 1998 E300 TurboDiesel, when I ask for more power at 70 mph and press the pedal down to the floor without inducing a downshift, I get some extra particulate. In fact, I am at a loss as to how the engine would respond to a demand for more power if you did not have the abiity to chuck some more fuel into the combustion chambers. Normally the driver is the feedback mechanism that decides if the car is running as it should for the conditions. The inter-relationship between boost pressure and fuel load is not in the driver's control loop, so the only thing the driver has to manipulate is the mechanical (or electro-mechanical in some cases) fuel enrichment lever.
To address your question directly we would have to know a little more about the situation than I do. Maybe others are more knowledgeable and can pipe in. But as I understand things from a steady state running condition to increase speed or climb a hill, the fuel is enriched first, then the boost climbs, and you settle at a new equillibrium. The driver controls this sequence with his/her right foot. So, in my opinion, unless 11 psi boost only happens with fuel load at maximum (pedal floored), then yes, at 11 psi boost you can have varying degrees of fuel enrichment, depending on the accelerator pedal position. In the case I was responding to, I believe the boost pressure might have been limited to something like 8 psi, and then, when the right foot signal arrived to ask for more power by enriching the mixture directly, the boost did not go up and the mixture stayed too rich, or richer than desired by the engine controls' normal measure of goodness, resulting in increased temps and some smoke out the back. My view on this is the driver has ultimate control since no electronics to date can understand the driver's intent and deal with it electronically. Jim
__________________
Own: 1986 Euro 190E 2.3-16 (291,000 miles), 1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000, 1988 300E 5-speed 252,000 miles, 1983 240D 4-speed, purchased w/136,000, now with 222,000 miles. 2009 ML320CDI Bluetec, 89,000 miles Owned: 1971 220D (250,000 miles plus, sold to father-in-law), 1975 240D (245,000 miles - died of body rot), 1991 350SD (176,560 miles, weakest Benz I have owned), 1999 C230 Sport (45,400 miles), 1982 240D (321,000 miles, put to sleep) |
#53
|
|||
|
|||
Quote:
Your right foot does clearly control the rack and allow more fuel to be delivered to the injectors. However, I'm not sure that the amount of fuel delivered can result in an overfueled condition when considering the OM603. |
#54
|
|||
|
|||
Brian,
You are correct in that the full "wide open throttle" event only occurs when the Alda or its electronic equivalent changes the effect of the mechanical stroke from the accelerator pedal to achieve the maximum available "effective" stroke of the rack. The stroke from the accelerator pedal is effectively "amplified" by the intake manifold pressure sensor value. However, in the original case I understood we were dealing with a case where the boost was 8 psi or something, not 11 psi. This kind of condition would give you the majority of the available "stroke" and enrich the fuel mixture to near its maximum if the pedal was floored. Without sufficient power to achieve whatever the driver's desire was, the engine may have had to labor in this condition for quite some time, leading to elevated temperatures. Anyway, my point was that I did not assume the original problem was "zero" boost, and I assumed whatever the actual condition was, it degraded performance enough that the engine was being over fueled for its output, leading to higher than desired temperatures. With "zero" boost it is probably unlikely you can enrich the mixture enough under nearly any circumstances to stress the cooling system design enough to see a temperature change. Jim
__________________
Own: 1986 Euro 190E 2.3-16 (291,000 miles), 1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000, 1988 300E 5-speed 252,000 miles, 1983 240D 4-speed, purchased w/136,000, now with 222,000 miles. 2009 ML320CDI Bluetec, 89,000 miles Owned: 1971 220D (250,000 miles plus, sold to father-in-law), 1975 240D (245,000 miles - died of body rot), 1991 350SD (176,560 miles, weakest Benz I have owned), 1999 C230 Sport (45,400 miles), 1982 240D (321,000 miles, put to sleep) |
#55
|
|||
|
|||
Quote:
If you can overfuel an OM603, and I am not at all confident that you can, it should be possible to do this independent of of the boost control and manifold pressure. Whether you can or cannot is dependent on the flyweights in the governor. They will not allow more than a certain amount of fuel at a given rpm. Now, if someone will tell me if the governor has a WOT setting where it dumps in some more fuel after your right foot hits the firewall, similar to old carburetors on gasoline engines, I would be most appreciative. |
#56
|
|||
|
|||
Interesting read! Today, I went ahead to make final adjustments to my alda from having freed it up a couple of weeks ago, as the push rod connecting linkages within the IP had rusted it seized. My 0 to 60 was 12.9 sec. @ 10 boost. Today after 1/2 turn CCW on alda, 0 to 60 12.7 @ 10+ boost. Turned the alda again 1/2 turn CCW and no change, turned alda yet again 1/2 turn and now 11+ boost but I did not have time to drive out to the hi-way again to check times, but it did clearly increase acceleration.
My only concern is that the alda set screw is now backed CCW as far as it will go! So I begin to wonder if the alda is dumping more fuel in, beyond the 11+ boost, the max I can only seem to get out of it. Yes I choked off the waste gate hose so it cant open. Steve........ |
#57
|
|||
|
|||
The ALDA is clearly dumping more fuel in with respect to a given boost pressure. This additional fuel is allowing the turbo to spin a little faster and provide a little more boost. However, with the wastgate hose pinched off, I still am a little perplexed why the boost will not climb up to the point where the overboost protection will kick in (15 psi or so).
You will need to keep an eye out for black smoke. You may have overfueled it trying to get the boost up. Also watch the fuel economy. If it drops by 10 to 15%, you have definitely overfueled it. |
#58
|
|||
|
|||
Quote:
The same with the governor weights. I believe they are a limiting feature, but I do not believe the normal operating condition under steady state is being limited by these items. It is my foot again. If I push the pedal to the floor, I get fuel enrichment until these items impose a limit. If everything was at a limit all the time, transient response would really suck, if you could get any at all. Jim
__________________
Own: 1986 Euro 190E 2.3-16 (291,000 miles), 1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000, 1988 300E 5-speed 252,000 miles, 1983 240D 4-speed, purchased w/136,000, now with 222,000 miles. 2009 ML320CDI Bluetec, 89,000 miles Owned: 1971 220D (250,000 miles plus, sold to father-in-law), 1975 240D (245,000 miles - died of body rot), 1991 350SD (176,560 miles, weakest Benz I have owned), 1999 C230 Sport (45,400 miles), 1982 240D (321,000 miles, put to sleep) |
#59
|
|||
|
|||
Quote:
Therefore, if the governor weights are limiting total fuel based upon rpm and the ALDA is limiting total fuel based upon manifold pressure, the engine is always running underfueled at steady state conditions. So, when you mash your foot, the rack opens to some specified limit and provides more fuel. The question remains whether you can overfuel it with your right foot, or are the controls for the ALDA and governor precise enough that you only can fully fuel it. That is the question. And, if you can overfuel it, is this by a special function of the IP when your right foot is mashed, or is it simply by accident because the rack cannot be calibrated that precisely to avoid overfueling and underfueling is out of the question because the engine won't make its specified horsepower. |
#60
|
|||
|
|||
Quote:
His premise is that the engine will run hotter if it is underboosted. This premise is true for a constant power level. This is best done by example: If the 603 has an output of 125 hp to climb a hill at 70 mph, it needs a specified amount of fuel, in lbs. per hour, to acheive this hp rating. Under normal conditions, the boost is probably running close to the maximum, say 10 psi. Now, let us say that the turbo is not functioning properly, or I have a crack in one of my boost lines (hello?) and the boost on this same hill drops to 6 psi. The fuel requirement in lbs. per hour, remains the same because the horsepower remains the same. If the ALDA backs down the fuel, then the only way I can get the same quantity of fuel per hour is to open the rack with my right foot. Now, we have a condition where the fuel is the same and the air is less. There is less air moving throught the engine to achieve the same horsepower. The engine is running a richer mixture, but it is not overfueled. It will likely run hotter under this condition. If AusMBTech had this in mind, he is correct. I stand corrected. Last edited by Brian Carlton; 09-17-2004 at 11:12 PM. |
Bookmarks |
Thread Tools | |
Display Modes | |
|
|