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#1
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W201 190E HVAC Vacuum Issues
Well, I replaced the heater core over the weekend and also double checked all vacuum connections while the dash was out. I noticed today that when I have the floor vents/partial defrost selection that I noticed at certain points while accelerating that I could hear more air flow from the defrost vents once in a while. More air blowing out of them than before I accelerated. Does not happen all the time just kind of random. Now I know that my vacuum resevoir is fine and all vacuum connections are fine as well. So I am asking if this is normal in certain circumstances due to the intake vacuum pressure dropping and just not holding the vent flap for the defroster half way open as it should be and just letting it open the rest of the way? Or is it a bad vacuum module for the vent flap? Of course I hope it is normal since I would have to remove the dash to get to that vacuum module again!
Also I have a slight noise in my Auto Tranny Shifter Selector! Sounds like pennies vibrating in an ash tray at high RPM's just before a shift! Really strange as it just started to happen and I also noticed that I get some sloppy clunking noises when I move the shifter. I can hear the workings more now than before. Is there some sort of bushing in there that may be bad and cause the shift level to vibrate or the linkages to vibrate on an Auto Tranny? Thanks,
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~Jamie _________________ 2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's. 1986 190E 2.3 Black, Auto, Mods to come soon..... |
#2
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Bump please!
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~Jamie _________________ 2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's. 1986 190E 2.3 Black, Auto, Mods to come soon..... |
#3
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Jaimie:
Make sure the check valve on the vacuum supply line is working. If not, you will lose vac on acceleration and the defrost flaps close. Otherwise, you have leaking rubber connectors on the switchover valve -- all of the right angle ones on the TE were bad when I replaced the evaporator. I would also check the actuators, likely some of them leak as well. You will need to purchase a MitiVac hand pump for diagnosis. Peter
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1972 220D ?? miles 1988 300E 200,012 1987 300D Turbo killed 9/25/07, 275,000 miles 1985 Volvo 740 GLE Turobodiesel 218,000 1972 280 SE 4.5 165, 000 - It runs! |
#4
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Thanks. I think it is the check valve. My flaps open when I accelerate, which I think is the default when there is no vacuum as I recall from when I had it apart. All my right angle connectors are good on my switct over now. I replaced the bad ones. So I guess the next thing will be the check valve! Can you just get them at the local parts store or are they special to MB?
__________________
~Jamie _________________ 2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's. 1986 190E 2.3 Black, Auto, Mods to come soon..... |
#5
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Any check valve at the auto parts store that fits will work (some blue ones for Fords fit nicely), but the MB ones will probably last considerably longer. The 32 year old ones on my 72 are fine, but the vac lock one on my brother's 75 failed.
Peter
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1972 220D ?? miles 1988 300E 200,012 1987 300D Turbo killed 9/25/07, 275,000 miles 1985 Volvo 740 GLE Turobodiesel 218,000 1972 280 SE 4.5 165, 000 - It runs! |
#6
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Quote:
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#7
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I ordered one today from *********************** and it was less than 7 bucks for it. 10 with shipping.
__________________
~Jamie _________________ 2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's. 1986 190E 2.3 Black, Auto, Mods to come soon..... |
#8
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They install by plugging into a rubber hose connector, just pull out and push in.
Make sure when you put it in that it holds vac on the passenger compartment side! Otherwise the AC system won't work at all. Peter
__________________
1972 220D ?? miles 1988 300E 200,012 1987 300D Turbo killed 9/25/07, 275,000 miles 1985 Volvo 740 GLE Turobodiesel 218,000 1972 280 SE 4.5 165, 000 - It runs! |
#9
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Quote:
P.S. Are these things actually called "Check Valves" because I couldn't find anything of the sort on the parts site. Thanks again |
#10
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Does the 98 use vacuum to control the HVAC system? I would think it would be electronically controller by then!
__________________
~Jamie _________________ 2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's. 1986 190E 2.3 Black, Auto, Mods to come soon..... |
#11
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Got new check valve and the same issue is there. Still not closing the heat valve either when I select off or coldest settings like it should either. Check all vacuum lines when I had the dash apart for heater core and no leaks anywhere. Also checked resevoir and heater valve operation if I actually suck on the lines and no leaks there either. I am getting very frustrated with this damn car. It still has an idle that I can feel and no matter what I do it still has it. Funny it runs smoother when the engine is cold than it does when hot and idling. I have replaced everything but the fuel injectors. Regulator, filter, sparks plugs, wires, cap, rotor, temp sensors, cleaned injectors by soaking in carb cleaner, replaced all rubber hoses on the intake from the IACV, I have done it all..... Any ideas???
__________________
~Jamie _________________ 2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's. 1986 190E 2.3 Black, Auto, Mods to come soon..... |
#12
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Bad injectors will certainly cause a rough idle, BTDT long ago on my Audi Fox. One that dribbles at idle will make it shake something terrible, and ajdusting the idle mix won't help.
However, if it runs smoothly cold, you probably have an overly lean mixture warm if the injectors are good, this will cause rough running. You should get a Mitivac hand pump to check the vac system, it has a guage so you can test for integrity. Sucking a vac by mouth will only detect major leaks in my experience, and you really don't want all the residual stuff in there in your mouth anyway! There are several restrictors in the system, so you will have dampers closing with only a minor drop if vac. Worst part I found on the TE after replacing all the servos and getting exactly what you have was leaking right angle fittings on the switchover valve. Minor leaks here allowed the dampers to partially close while accelerating. You should have a reservior in the system to "float" it over the low vac caused by acceleration. However, if the mxture is off, you will be low on vac anyway, and will no have enough. Peter
__________________
1972 220D ?? miles 1988 300E 200,012 1987 300D Turbo killed 9/25/07, 275,000 miles 1985 Volvo 740 GLE Turobodiesel 218,000 1972 280 SE 4.5 165, 000 - It runs! |
#13
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Quote:
__________________
~Jamie _________________ 2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's. 1986 190E 2.3 Black, Auto, Mods to come soon..... |
#14
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Replace the fuel filter and check the fuel pump relay -- if it's hot after running a bit, replace it, this may cure the rough idle, lack of power, and occasional stalls while running.
Peter
__________________
1972 220D ?? miles 1988 300E 200,012 1987 300D Turbo killed 9/25/07, 275,000 miles 1985 Volvo 740 GLE Turobodiesel 218,000 1972 280 SE 4.5 165, 000 - It runs! |
#15
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Quote:
Brand new filter and the relay does not get hot as far as I remember, but I will check it at lunch after I have ran it. Thanks again, and I am leaning toward injectors since I have replaced everything but the fuel pump and AFM.
__________________
~Jamie _________________ 2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's. 1986 190E 2.3 Black, Auto, Mods to come soon..... |
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