erratic idle 280i
Discussion
Hi Mate..
Could be a number of things causing it..Is the Auxillary Air Device working?..You can test them by taking it off and warming it up with a heat gun gently to see if its closing..Or clamp the pipe when the car has warmed up,If there is no change in revs or idle then its working ok...Ziga
Could be a number of things causing it..Is the Auxillary Air Device working?..You can test them by taking it off and warming it up with a heat gun gently to see if its closing..Or clamp the pipe when the car has warmed up,If there is no change in revs or idle then its working ok...Ziga
Hi Ivan..
Sometimes the can become gummed up, I cleaned mine with carburettor cleaner..I took it off and sprayed down one end and gently shook the unit, I repeated this a few times..Tested it by warming up the diaphragm (the big round bit in the middle) with a hot air gun untill i saw the flap close..Allowed to cool to make sure it opened again..Re-fitted..Good luck..Ziga
Sometimes the can become gummed up, I cleaned mine with carburettor cleaner..I took it off and sprayed down one end and gently shook the unit, I repeated this a few times..Tested it by warming up the diaphragm (the big round bit in the middle) with a hot air gun untill i saw the flap close..Allowed to cool to make sure it opened again..Re-fitted..Good luck..Ziga
ivan segal said:
Hi:
my 280i after warm-up when I stop the idle makes wild swings 675-1200 etc. I believe it's an air problem..please help.. Ivan
Known as hunting, it's caused by a lean fuel mixture, as you say only when warm as from cold you have fuel enrichment. As to the cause, it wont be the AAD, as said they should be open when cold and shut when hot, the AAD is to raise RPM during warm up, so for this to be causing hunting it would have to be repeatedly opening and closing, which they just don't do.my 280i after warm-up when I stop the idle makes wild swings 675-1200 etc. I believe it's an air problem..please help.. Ivan
You need to check your fuel pressures first, if that's correct then check your emissions, they can be adjusted with a 3mm allen key after the adjustment plug is removed (located between the air sensor plate and the metering unit. However, the mixture should not need adjustment unless something has changed, and that something would either have to be fuel pressure or the mixture screw has moved, which would be very unusual.
Chris.
dixiebabes said:
Cant wait to meet Zig at the BBWF he sounds like a rusty nail runner in the making!!!
Dix
Same here mate,,In fact im looking forward to meeting everyone..Its only 11 weeks away or so..Come to think about it we havent had a days count down for a while..(pwd)?..Come on..Dix
Will have to book me room at the hotel soon..South facing penthouse sweet..With extras thrown in..And specials services..
taz turbo said:
Known as hunting, it's caused by a lean fuel mixture, as you say only when warm as from cold you have fuel enrichment. As to the cause, it wont be the AAD, as said they should be open when cold and shut when hot, the AAD is to raise RPM during warm up, so for this to be causing hunting it would have to be repeatedly opening and closing, which they just don't do.
You need to check your fuel pressures first, if that's correct then check your emissions, they can be adjusted with a 3mm allen key after the adjustment plug is removed (located between the air sensor plate and the metering unit. However, the mixture should not need adjustment unless something has changed, and that something would either have to be fuel pressure or the mixture screw has moved, which would be very unusual.
Chris.
Agreed weak mixture. Might be caused by damaged or loose hose from AAD to plenum or brake servo hose, or, even the servo leaking air. With engine running I spray brake cleaner, as it's fairly inflammable, around suspect areas and see if engine revs pick up. If they do that's where the problem may lies. You need to check your fuel pressures first, if that's correct then check your emissions, they can be adjusted with a 3mm allen key after the adjustment plug is removed (located between the air sensor plate and the metering unit. However, the mixture should not need adjustment unless something has changed, and that something would either have to be fuel pressure or the mixture screw has moved, which would be very unusual.
Chris.
MJG280 said:
taz turbo said:
Known as hunting, it's caused by a lean fuel mixture, as you say only when warm as from cold you have fuel enrichment. As to the cause, it wont be the AAD, as said they should be open when cold and shut when hot, the AAD is to raise RPM during warm up, so for this to be causing hunting it would have to be repeatedly opening and closing, which they just don't do.
You need to check your fuel pressures first, if that's correct then check your emissions, they can be adjusted with a 3mm allen key after the adjustment plug is removed (located between the air sensor plate and the metering unit. However, the mixture should not need adjustment unless something has changed, and that something would either have to be fuel pressure or the mixture screw has moved, which would be very unusual.
Chris.
Agreed weak mixture. Might be caused by damaged or loose hose from AAD to plenum or brake servo hose, or, even the servo leaking air. With engine running I spray brake cleaner, as it's fairly inflammable, around suspect areas and see if engine revs pick up. If they do that's where the problem may lies. You need to check your fuel pressures first, if that's correct then check your emissions, they can be adjusted with a 3mm allen key after the adjustment plug is removed (located between the air sensor plate and the metering unit. However, the mixture should not need adjustment unless something has changed, and that something would either have to be fuel pressure or the mixture screw has moved, which would be very unusual.
Chris.
Spraying brake cleaner should find your air leak, distrib hose would be my first guess. No leak..... clamp or remove the dist vac hose...sticking bob weight maybe. You could get away with lubing the dist shaft with some thin stuff.
"Always look on the bright side of life"..
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