twinsnail

my 2001 996 tt tip is making a high pitched whine at start, again at about 3 minutes; I assume this is the air/smog pump with some bad bearings
1 does everybody agree? 2 how tough a job is it replace this pump? Lets use diverter replacement as a comparison
thanks

1999Porsche911

Don't assume anything. Unplug the pump and see if the noise is eliminated.

twinsnail

thanks, good idea, but i am confident that this is the air pump; it sits in a position that might be reachable by me; anyone changed one of these?

KPG

I have taken it out couple of times to install a 5Bar FPR...an hour labor, small hands a plus. Kevin

twinsnail

thanks, will give it a go

wross996tt

So I'm confused...you ask if we agree...1999 offers a way to check and you aren't interested??? I would also ask for more detail, but apparently you aren't interested and just want to change the pump out. Good luck.

esemes

is the pump even needed (aside from emissions??)

mine's a bit noisy at cold-start, but quiets very quickly......

twinsnail

job is done, i was looking for someone who knew about these pumps; they are smog pumps, they are not needed in a performance sense, they have bushings (not bearings) i discovered, they do cycle per input to cpu and they do bring up your check engine light when output is low, cost for pump is $1200, about $600 used mine went at 52,000 miles; thanks KPG Sorry you are confused wross

99firehawk

they are all noisey at start up, as long as you dont have a cel why bother? the noise only lasts about 2 minutes at the most


and no its only used for the secondary air system, if you had someone whit a piwis/pst2 they could tell your car it was a row car and it would never turn on

twinsnail

thanks, that is the kind of discussion i was hoping for; when yours goes you will know the difference in the sound I am guessing that alot of 996 tt's are not driven as much as mine; 100 mi/day
Many of the issues I had with my other Porsches were at high mileage and i had trouble finding cars with as many miles to compare I'm not sure who you were addressing that last comment to

99firehawk

i have never seen one with failed bearings, or bushings even on 100k mile cars
i have seen a handfull where the filter was so dirty it was restrciting the pump and changing the sound of the pump but never internal failure

wross996tt

That is just his sig...not intended at anyone in particular unless you feel guilty.

twinsnail

thanks, leave it to me to have a $1,200 pump failure (I was also fortunate enough to have my {perfectly maintained} 996 carrera motor grenade itself at low revs) I actually made this switch because of the dry sump case but I am now hooked on the boost These are fantastic cars