928 S4 Air Pump Noise
12-23-2001, 01:11 PM
#1
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928 S4 Air Pump Noise
My 928 S4 has done 143K miles (just run in) and my air pump makes a loud nocking noise. Can this be serviced, or do I throw it away?
My cruise control only lasts for 10 seconds before it fades away.Is this a vacuum problem?
I can no longer trim my headlights, and have been told that this is an expensive repair job. Should I just live with this small disadvantage?
Thanks,
John V
My cruise control only lasts for 10 seconds before it fades away.Is this a vacuum problem?
I can no longer trim my headlights, and have been told that this is an expensive repair job. Should I just live with this small disadvantage?
Thanks,
John V
12-23-2001, 02:47 PM
#2
John,
I am, personally, unfamiliar with the 928 smog pump. BUT, WAIT!
There are several posts and replies on the subject since June...roll back thru the pages or use the search feature and go archive diving.
There is also some good specifics on the Nichol's site.
There are 3 main schools of thought:
1.Replace/repair - running a distant 3rd -.
2.Remove the pump and replace with a Euro(?) bracket and pulley sans the pump - a part number on the Nichol's site -. Removes some parasitic drag. Money involved here, me-thinks.
3.Leave the puppy hang there for Inspection purposes and get a shorter belt - you reduce parasitic drag but not the weight - the belt numbers are on the Nichols site but I would use the most current (local parts store) numbers from recent posts as they are cheaper/readily available/and have worked, RECENTLY!
As to the noise, on American units that I have disassembled there are nylon/teflon or,
the like vanes pushed into slots on a ...
drum... for the lack of the proper word.
These vanes appear to be angled front to rear in order - I guess - to compress vented crankcase fumes - could be wrong here - and send them on a journey thru the combustion chambers.
Interestingly, if one vane starts wearing before the others - I've seen up to 8 vanes -
the drum shaft which is bushed - no bearings-developes a wobble and the other vanes either start wearing oddly or after a while some break off in either case the wobble gets worse and you hear a flapping sound or in the later stages a knocking sound as the drum bushings get progressively elongated from the worsening out of balance condition.
If you go with #3 remove the old - longer - belt 'tag'and zip lock it and put it the spare tie wheel with the other stuff you or the next owner may need it.
HTH/LOL
Keep em' rolling.
John S. 82'Weissach, Auto., 'Pattycakes'
P.S. Other than the irritating noise I've don't believe the problem could cause any damage, except to the drive belt and that would require the shaft to fall into the compressor cavity proper, jam the pulley and eventually destoy the belt. Real long shot...
but with a beloved sHARk it is ALWAYS best to play it safe - especially, if the repair is fairly easy to do and inexpensive.
I am, personally, unfamiliar with the 928 smog pump. BUT, WAIT!
There are several posts and replies on the subject since June...roll back thru the pages or use the search feature and go archive diving.
There is also some good specifics on the Nichol's site.
There are 3 main schools of thought:
1.Replace/repair - running a distant 3rd -.
2.Remove the pump and replace with a Euro(?) bracket and pulley sans the pump - a part number on the Nichol's site -. Removes some parasitic drag. Money involved here, me-thinks.
3.Leave the puppy hang there for Inspection purposes and get a shorter belt - you reduce parasitic drag but not the weight - the belt numbers are on the Nichols site but I would use the most current (local parts store) numbers from recent posts as they are cheaper/readily available/and have worked, RECENTLY!
As to the noise, on American units that I have disassembled there are nylon/teflon or,
the like vanes pushed into slots on a ...
drum... for the lack of the proper word.
These vanes appear to be angled front to rear in order - I guess - to compress vented crankcase fumes - could be wrong here - and send them on a journey thru the combustion chambers.
Interestingly, if one vane starts wearing before the others - I've seen up to 8 vanes -
the drum shaft which is bushed - no bearings-developes a wobble and the other vanes either start wearing oddly or after a while some break off in either case the wobble gets worse and you hear a flapping sound or in the later stages a knocking sound as the drum bushings get progressively elongated from the worsening out of balance condition.
If you go with #3 remove the old - longer - belt 'tag'and zip lock it and put it the spare tie wheel with the other stuff you or the next owner may need it.
HTH/LOL
Keep em' rolling.
John S. 82'Weissach, Auto., 'Pattycakes'
P.S. Other than the irritating noise I've don't believe the problem could cause any damage, except to the drive belt and that would require the shaft to fall into the compressor cavity proper, jam the pulley and eventually destoy the belt. Real long shot...
but with a beloved sHARk it is ALWAYS best to play it safe - especially, if the repair is fairly easy to do and inexpensive.
12-23-2001, 03:00 PM
#3
John,
Me again, forgot the other two items.
The headlight trim cure should, also, be in the June till now pages.
Nichol's site for the cruise issues.
While you are tinkering with the cruise you should be able to cure any AC/Heater (HAVC) problems. Check on both at the Nichols site and you should see overlapping areas of interest - solinoids, vac. lines, relays -.
Please excuse several mispellings on previous
reply.
Later,
John S. & Pattycakes
Me again, forgot the other two items.
The headlight trim cure should, also, be in the June till now pages.
Nichol's site for the cruise issues.
While you are tinkering with the cruise you should be able to cure any AC/Heater (HAVC) problems. Check on both at the Nichols site and you should see overlapping areas of interest - solinoids, vac. lines, relays -.
Please excuse several mispellings on previous
reply.
Later,
John S. & Pattycakes
12-14-2002, 10:48 AM
#4
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These vanes appear to be angled front to rear in order - I guess - to compress vented crankcase fumes - could be wrong here - and send them on a journey thru the combustion chambers.
Actually, the pump takes plain ol' air and pumps it into the catalytic converter to help keep the HC down. It diverts the air flow into the intake housing sometime depending upon a vacuum in the throttle body.
Actually, the pump takes plain ol' air and pumps it into the catalytic converter to help keep the HC down. It diverts the air flow into the intake housing sometime depending upon a vacuum in the throttle body.
