280 hard start and idle issue
Discussion
Ah I see...So what happens if once warmed up to temp you blip the throttle via the butterfly on the throttle housing/body...does it return to idle smoothly?..or does it drop in rpm and then pick up...?...If yes then your fuel mixture is out....this will need an adjustment on the sensor plate/metering head....we are only talking 1/4" turn here though....
Hi Charlie.
Once car is up to temp....Its best with a long allen key.. place the long hex driver etc into the adjuster but pay real close attention to what position it is in was before touching it...like 12 o'clock etc..make a note or take a pic..mark somewhere with tippex on the metering unit where it was also..small increments of 1/4"...Sorry cannot remember lean or rich but try it one way..blip throttle..don't leave the driver in there but again it is imperative that you know what position it was in before removing etc..If moving it one way does nothing...turn it back to where it was and try the same measurement the opposite way...It wont be out by too much and you will find the sweet spot....
Good luck
Once car is up to temp....Its best with a long allen key.. place the long hex driver etc into the adjuster but pay real close attention to what position it is in was before touching it...like 12 o'clock etc..make a note or take a pic..mark somewhere with tippex on the metering unit where it was also..small increments of 1/4"...Sorry cannot remember lean or rich but try it one way..blip throttle..don't leave the driver in there but again it is imperative that you know what position it was in before removing etc..If moving it one way does nothing...turn it back to where it was and try the same measurement the opposite way...It wont be out by too much and you will find the sweet spot....
Good luck
Dropping engine revs when pressing clutch pedal more likely to be a seized release bearing.
On a car that sits and is not driven much, it could free itself, I would sooner sit in the driveway and operate the pedal all day in the hope that happens rather than pull the box.
ETA that's pressing the pedal with motor running obviously.
On a car that sits and is not driven much, it could free itself, I would sooner sit in the driveway and operate the pedal all day in the hope that happens rather than pull the box.
ETA that's pressing the pedal with motor running obviously.
Edited by jeff m2 on Friday 6th September 02:34
Close the butterfly "gently" using the stop adjustment, back off half a turn, tighten lock nut.
The purpose is only to prevent the butterfly sticking
Air flow adjustment is done using the screw in the by pass below the butterfly. Aim for 850 when warm. Although you could set it a lttle higher until you find the source of your prob
The purpose is only to prevent the butterfly sticking
Air flow adjustment is done using the screw in the by pass below the butterfly. Aim for 850 when warm. Although you could set it a lttle higher until you find the source of your prob
Hi mate
Sorry I didn't get back to you as regards to the butterfly, if it is increasing in idle when warming up then this would kind of suggest that something is opening up to create a leak so I would be looking around air hoses etc, also check to see if the inlet manifold is not leaking, a common place is where the distributor is.
To test:
Once car has reached normal operating temperature the remove the oil filler cap and place the palm of your hand over the opening, rev via the throttle linkage and see if your palm gets sucked to the opening, if yes then this is a sign of a leaking inlet manifold.
Hope this helps
Ziga
Sorry I didn't get back to you as regards to the butterfly, if it is increasing in idle when warming up then this would kind of suggest that something is opening up to create a leak so I would be looking around air hoses etc, also check to see if the inlet manifold is not leaking, a common place is where the distributor is.
To test:
Once car has reached normal operating temperature the remove the oil filler cap and place the palm of your hand over the opening, rev via the throttle linkage and see if your palm gets sucked to the opening, if yes then this is a sign of a leaking inlet manifold.
Hope this helps
Ziga
With the rpm at 1500 squeeze the black air hose going into the Aux Air Device, if the rpm drop then it means your AAD is not closing when hot.
AAD should be open at cold, closed at hot.
Pull off the hose you will see a small disc that shuts off the cold start air flow.
Although you may not see it if it is stuck open
You can de-gunk it in situ with a spray, but it's only a a couple of bolts to remove it and soak it Chem plus 12 or similar then check it with physical heat to make sure the disc is moving.
Once the AAD is operating go back and adj the air by pass screw to get your hot idle where it needs to be.
PS it is generally a good idea to only adj things in the correct order. Check your thermotime swich and AAD are OK and no obvious air leaks.
You can spray almost anything (not petrol) usually brake cleaner around all hose connections plugs etc, if there is a leak you will hear engine note change (improve)
I would stay away from adjusting the idle mixture, that ireally should only be done after all the system and control pressures are known to be correct.
AAD should be open at cold, closed at hot.
Pull off the hose you will see a small disc that shuts off the cold start air flow.
Although you may not see it if it is stuck open
You can de-gunk it in situ with a spray, but it's only a a couple of bolts to remove it and soak it Chem plus 12 or similar then check it with physical heat to make sure the disc is moving.
Once the AAD is operating go back and adj the air by pass screw to get your hot idle where it needs to be.
PS it is generally a good idea to only adj things in the correct order. Check your thermotime swich and AAD are OK and no obvious air leaks.
You can spray almost anything (not petrol) usually brake cleaner around all hose connections plugs etc, if there is a leak you will hear engine note change (improve)
I would stay away from adjusting the idle mixture, that ireally should only be done after all the system and control pressures are known to be correct.
Edited by jeff m2 on Wednesday 25th September 18:55
jeff m2 said:
With the rpm at 1500 squeeze the black air hose going into the Aux Air Device, if the rpm drop then it means your AAD is not closing when hot.
AAD should be open at cold, closed at hot.
Pull off the hose you will see a small disc that shuts off the cold start air flow.
Although you may not see it if it is stuck open
You can de-gunk it in situ with a spray, but it's only a a couple of bolts to remove it and soak it Chem plus 12 or similar then check it with physical heat to make sure the disc is moving.
Once the AAD is operating go back and adj the air by pass screw to get your hot idle where it needs to be.
PS it is generally a good idea to only adj things in the correct order. Check your thermotime swich and AAD are OK and no obvious air leaks.
You can spray almost anything (not petrol) usually brake cleaner around all hose connections plugs etc, if there is a leak you will hear engine note change (improve)
I would stay away from adjusting the idle mixture, that ireally should only be done after all the system and control pressures are known to be correct.
Anyone know how fast the AAD should open and close? I think mine was sticky, so i cleaned it, but dont know how long it should take from fully open to fully closed when heated. Seems to take a while when heating with a heat gun.AAD should be open at cold, closed at hot.
Pull off the hose you will see a small disc that shuts off the cold start air flow.
Although you may not see it if it is stuck open
You can de-gunk it in situ with a spray, but it's only a a couple of bolts to remove it and soak it Chem plus 12 or similar then check it with physical heat to make sure the disc is moving.
Once the AAD is operating go back and adj the air by pass screw to get your hot idle where it needs to be.
PS it is generally a good idea to only adj things in the correct order. Check your thermotime swich and AAD are OK and no obvious air leaks.
You can spray almost anything (not petrol) usually brake cleaner around all hose connections plugs etc, if there is a leak you will hear engine note change (improve)
I would stay away from adjusting the idle mixture, that ireally should only be done after all the system and control pressures are known to be correct.
Edited by jeff m2 on Wednesday 25th September 18:55
Hi mate
The last time I tested one it took around 2-3 mins to close, I then put it in the refrigerator and it took around the same time to open..I did spray brake & clutch cleaner in there a couple of times, covered the openings with thumb and second finger and shook it up..worked fine after that.
Ziga
The last time I tested one it took around 2-3 mins to close, I then put it in the refrigerator and it took around the same time to open..I did spray brake & clutch cleaner in there a couple of times, covered the openings with thumb and second finger and shook it up..worked fine after that.
Ziga
I checked the AAD and it's functioning as it should. I rotated the mixture screw in the fuel distributor a 1/4 turn CCW and now it doesn't stall. The RPMs still dip but it recovers. Might need a 1/4 more. It's still idling high so I need to go over the setting of the butterfly in the inlet of the manifold and set it correctly. I have a feeler gauge clearance setting for my 350i but no info on the 280i. I have set it at 3/16 clearance between the mechanism and the stop on the top of the manifold. Not sure what it's at currently. Then go back and set the idle screw.
I think the idle screw should be fully closed and then backed out two turns.
Any other things to try??
Also, my temp gauge seems to have quit. Anyone have a part number to replace it? I have Smiths gauges.
I think the idle screw should be fully closed and then backed out two turns.
Any other things to try??
Also, my temp gauge seems to have quit. Anyone have a part number to replace it? I have Smiths gauges.
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