Whistle sound

[moosey]

1999 boxster w/ 155K . I noticed right after changing the O2 sensor before the cats that 1 in 5 starts cold or hot starts i get a loud whistle sound when the car is started and goes away immediatley. Car drives perferct and normal after the 1 second sound at start up. The sound seems to be coming from passenger rear. Everything has been replaced on the car except fuel pump. Should i change the fuel pump by now if i see no signs of trouble? Thanks

[JFP in PA]

If your fuel pump ever does decide to start whistling, you will be in trouble because they simply do not do that.

Are you sure that you properly torqued the new o2 sensors when you installed them? Very small exhaust leaks can whistle. I'd put the car up in the air and cold start it while looking and listening where you think it is coming from..........

[EleCTriCT]

Sounds like a loose spark plug..... seen this a few times on boxsters. I think torque is around 18 - 22 ft lbs.

Of course the above mentioned is also very likely..

Would love to hear about your findings...

Cheers

[moosey]

Sounds like a loose spark plug..... seen this a few times on boxsters. I think torque is around 18 - 22 ft lbs.

Of course the above mentioned is also very likely..

Would love to hear about your findings...

thanks, will check all plugs and pretty sure o2 sensor is snug on there.

Cheers

[JFP in PA]

You might be surprised, we have had factory cars come in with this type of complaint and found O2 sensors that were either finger tight, or partially unscrewed. A quick tightening was all that was required to silence the noise.

[moosey]

If your fuel pump ever does decide to start whistling, you will be in trouble because they simply do not do that. Are you sure that you properly torqued the new o2 sensors when you installed them? Very small exhaust leaks can whistle. I'd put the car up in the air and cold start it while looking and listening where you think it is coming from..........

Just checked the o2 sensor and it is nice and snug, checked the spark plugs and they were all snug as well, but i did find that three of the passenger side coil packs had slight cracks not too deep though. Could this cause the whistle. I just replaced the coil packs and plugs no less than two years ago.

[JFP in PA]

I cannot say that I have ever encountered a coil pack making a sound.

[adonkin]

Moosey,

See if the sound is coming from under your fuel fill door. The coke bottle blown accros the top sound was driving me nuts till I checked the board and got a suggestion to dampen the sound coming from the carbon canister vent pipe with a small piece of open cell foam. That worked for two years on my 2000 2.7 till last fall - but that is another story.

Alan in Boston

[EleCTriCT]

Like JFP said, coild packs dont make noise, at most an arching sound when they are bad and leak spark.... note that if your coils are cracked (which is common with these) you might start getting missfires in wet weather....

As for the noise during startup now im thinking it is the starter motor... probably making a zinging noise just after you let go of the key like its not disengaging... This is also very common amongst porsche and v.a.g. starter motors... Look into that.....

Ive seen starters still functioning reliably for a long while making the noise... but as a technician i would still recommend replacing it... if that is the noise of course...

best of luck

[moosey]

Like JFP said, coild packs dont make noise, at most an arching sound when they are bad and leak spark.... note that if your coils are cracked (which is common with these) you might start getting missfires in wet weather....

As for the noise during startup now im thinking it is the starter motor... probably making a zinging noise just after you let go of the key like its not disengaging... This is also very common amongst porsche and v.a.g. starter motors... Look into that.....

Ive seen starters still functioning reliably for a long while making the noise... but as a technician i would still recommend replacing it... if that is the noise of course...

best of luck

Thanks , I dont know what else it can be. Its just funny that it happened right after I replaced an O2 sensor. Checked everything but I was starting to think it could be the starter because the sound does come and go quickly once the key is let go.

[Stefan]

Sounds like your starter bendix is sticking. If that's it, take out the starter and lube the bendix and you'll be good. No need to replace anything. Common problem.

Edited March 6, 2012 by Stefan