Engine sounds like a diesel when cold
 

My recently acquired P5 (2002) sounds like a tractor when it's cold - it goes away when warm. Looking through older posts, it seems that there is a TSB for this and an ecu reprogram might help.
Will the dealer fix this under warranty? Someone mentioned that the dealers have to put a TSB sticker next to the emissions sticker if this is done - whereabouts on the car can I find this?

Thanks for any help.

this isn't a problem with your car and the dealer won't do anything to fix it. The TSB says that there is no action needed as this is not a problem.

The noise your hearing is engine trying to warm the car up faster by dumping raw gasoline into the pre-cat. It makes a noise like a deisel until it warms up....this is natural. Nothing to be worried about .

Hmmm. I have noticed that the engine warms up mighty quickly - just a minute or so, but even if this is really not a problem, I'm surprised that there aren't more people mentioning it. What is the "pre-cat" by the way?

catalytic converter bolted directly to the exhaust manifold. The second cat is after the downpipe section.

OK. Thanks!

i'd quickly be disabling that feature with gas prices being as high as they are :p...

thanks you answered one of my questions, here i thought it was a loose valve spring or something

actually, getting the car to operating temperature faster will SAVE you gas.

cool, I always thought that was vlave clatter or big rod end noise...phew I feel better

i never pay it any attention because my radio is always on and I can't hear anything over that noise.

you're not the only one! i noticed it too and was beginning to get a little worried about it.

yeah, I was getting to the point of bumping the motor a few times before I started it..now I can stop that

c'mon people, how long have you owned mazdas mazda prides itself on having the worlds smallest tappets (lifters) unfortunately these make noise especially when cold so change your oil frequently to keep them sludge free!!!!!!!!!!!! the sound is normal if it goes away quickly!!!!!!!!!!!!!!

yes there is a TSB for it.... the dealer will reprogram your ECU and it is completely under warranty. it only happens on older models for proteges, 2002 and 2002.5, but don't quote me cause i dunno if they updated the ECU for the 2002.5 models yet...

o yea... they will have to check your vin number to verify that your ECU is within that batch that makes this horrible sound during the warm up.

it wouldn't really bust your engine if you don't go fix it. i'm guess that its just a sound thing.... if you can live with it then you porbably don't have to go fix it.

OK - so now there's conflicting opinions...

Either it's noise caused by fuel being injected into the pre-cat or it's noise from the lifters, and either it will be "fixed" under warranty, or it won't.
Please can someone who actually has the technical knowledge and not just speculating, please explain:

a) What is causing this noise?
b) Is it harmful to the engine?
c) Will the dealer "rectify" this under warranty (I imagine that it is not actually harmful, just that my car sounds horrible when cold)?

To reiterate, the noise is not any sort of rattle, whine or buzz - the engine just sounds "wooly" and "fluttery" (like a diesel engine), but only when it is cold.

Thanks!