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#1
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Overactive AAV idle control w108 4.5
This engine has an Auxiliary Air Valve that is supposed to regulate idle speed, it higher idle when cold and lower when warm. Well, mine seems to be overactive, as the car idles way too fast when cold (1 minute after warmup it will be so high that the ECU will cut fuel, then it falls and gets fuel again, ecu cuts fuel, etc), but too slow when warm.
Is there anything I can do about this? Thanks in advance.
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Csaba 1972 280SEL 4.5, silver |
#2
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You sure it's not the temp sensor?
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With best regards Al |
#3
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The coolant temp sensor for the ECU? When it's bad or disconnected the mixture will be ridiculously rich, so I don't think that's what it is, but I will check it anyways.
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Csaba 1972 280SEL 4.5, silver |
#4
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Turn the screw in to let less air through and keep warm idle up using the mixture screw on the ECU. That's what I did. Other than crimping the bulb tighter, that's about all you can do I think.
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Current: 2021 Charger Scat Pack Widebody "Sinabee" 2018 Durango R/T Previous: 1972 280SE 4.5 2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi" 1999 Chrysler 300M - RIP @ 221k |
#5
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Thanks, I will try that.
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Csaba 1972 280SEL 4.5, silver |
#6
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I should add, you can do the opposite as well, if that works better in your case. Use the knob to lower cold idle and screw on the ECU to raise warm.
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Current: 2021 Charger Scat Pack Widebody "Sinabee" 2018 Durango R/T Previous: 1972 280SE 4.5 2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi" 1999 Chrysler 300M - RIP @ 221k |
#7
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The mechanical bits in this devise get stuck sometimes. Remove the rubber connector pipe and spray in some WD40. Works for me when the idle mechanism gets cranky.
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Berfinroy in CT Present vehicles: 1973 300 SEL 4.5 1959 Rolls Royce Silver Cloud I 1959 Ford Thunderbird convertible/430 Past vehicles; 1958 Bentley S 1 1976 ex-Max Hoffman 6.9 1970 300SEL 2.8 1958 Jaguar MK IX 1961 Jaguar MK IX 1963 Jaguar E-type factory special roadster 1948 Plymouth woody 1955 Morgan plus 4 1966 Shelby GT350H Mustang |
#8
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Gentlemen,
I open and repair as much as I could my AAV. Is this normal open position? And, when reinstalling, should I consider some gasket sealant liquid over the gasket or just the gasket as it is?
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1972 W108 280SE 4.5 1977 W116 450SEL 1981 E12 528i BMW |
#9
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No, It should open more, and close when hot. (place in pot ofhot water) There are vids on youtube on cleaning them.
just the gasket. |
#10
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Quote:
I pressed the bulb, maybe too much. I think That’s why it is so much closed. Would it cause any trouble with just that opening?
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1972 W108 280SE 4.5 1977 W116 450SEL 1981 E12 528i BMW Last edited by Adv_rider; 08-05-2020 at 02:24 PM. |
#11
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We've installed a washer in the rubber hose so that most of the extra air was shut off or sometimes we close it off completely. Engine runs poorly when cold but fine once it warms a bit.
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#12
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thanks for the info.
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1972 W108 280SE 4.5 1977 W116 450SEL 1981 E12 528i BMW |
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