I have a theory on the Protege rattle that has plagued the 2.0L cars the most...

As a refresher, this rattle comes from the engine compartment, especially when the engine is cold and warming up. I believe one member has referred to it as a lawnmower sound.

I had this rattle, though not as severe, on my 1.8L. It would come on during warm-up, during idle-down (when the ECU holds rpms just above idle for a few seconds before returning to idle), and occasionly while idling. It was rather annoying and noticeable.

This rattle went away after my Injen CAI was installed. However, it was replaced by a nasty tick, tick, tick, tick, tick, tick sound during the same instances the rattle used to occur. This tick was about twice as fast as the turn signal and much louder. This was even more embarassing and annoying than the rattle!

I traced the tick to the purge solenoid valve. This valve is a small vacuum control valve which has two vacuum hoses and an electrical connection. One vacuum hose goes to the throttle body while the other goes to the charcoal vapor recovery canister mounted on the passenger-side firewall. I inquired at my local dealership and a technician looked up the valve. It is normal for it to quickly cycle on and off, hence the tick.

Stock, this valve is mounted on the plastic intake between the MAF and throttle body. The stock intake is loosely put together and is made of a hard plastic. A vibration caused by this valve could easily make the rattle sound we all hate. We all know it is not a metallic rattle... hard plastic makes sense.

When Injen installed their CAI, they moved the purge solenoid valve to a bracket mounted on the firewall. Being mounted there, the cycling is transmitted directly to the firewall and into the passenger compartment. Hence the loud tick, tick, tick. I remounted it using soft rubber washers, but it only made the tick a bit more quiet. Finally, I moved the valve to the intake manifold where the VTCS connector is. Guess what? No more rattle and no more ticking. The vibration is transferred directly to the engine and is absorbed by the engine mounts. Finally, peace after 3.5 years!

I know this post is long... but I was wondering if any of the technical guys in here could look it over and see if it makes sense. I know a make-shift solution to the rattle was made by unplugging the VTCS connector. Is the VTCS system somehow connected to the purge solenoid valve? I don't have VTCS, so I can't trace it. They're both emissions related. Perhaps someone can try it? This can be simply done by unplugging the purge solenoid valve (mounted on the intake between the MAF and throttle body). If this works, perhaps we could recommend it to Mazda and they could find a new place to put this valve and then fix everyone's annoying rattle...

Thanks,

Jerry

 

Hmmm... Well, I haven't experienced the rattle (yet!), but having a P5, I've followed the threads quite intimately... just in case.

I'd just like to say that out of all the ideas, theories, etc... this one seems the most sound so far. I'd like to see if others are able to get rid of the rattle the same way.

Good bit of investigative work there

 

You are partly correct, butthis "rattle" is a known issue, and Mazda has issued a bulletin to all the dealers about it. There is no fix right now, but at least the issue is documented:

The rattle is caused by the VTCS (variable timing control solenoid). This solenoid changes the timing of the car when cold, allowing for far less emissions during warm-up - this is how the Pro5 (and sedans, but NOT the MP3) have ULEV (ultra low emissions vehicle) status.

Now as fas I know it is not the solenoid itself that causes the rattle, it is what the solenoid controls - it is a timing-related rattling. Someone here posted that they disconnected the vacuums to the solenoid - but re-connected the in and out vacuum tubes to one another (basically bypassing the solenoid) and the rattle went away completely. Simply unplugging the thing will cause check engine warnings and trouble codes.

The rattling has - at least for now - been determined to not cause any engine damage - it's just a rattle, nothing more. But if it bothers you that much, do a search, and follow the instructions to bypass the solenoid, and you will have no more rattle, guaranteed.

The MP3 does not have this solenoid or VTCS system - they have no reports of any engine rattling like the P5 and 2.0L sedans.

 

I am familiar with the Mazda service bulletin.

However, the VTCS has nothing to do with the timing of the engine. VTCS is an acronym for Variable Tumble Control System. It activates small vanes or valves which controls how the intake air tumbles or swirls into the combustion chamber. This aids atomization of the fuel and attains a more complete burn with less emitted unburned hydrocarbons.

The VTCS does not cause the rattling. If the VTCS were the problem, all 2.0L Protege sedans and Protege5's would have the rattle. There is something else causing this, but apparently the VTCS has something to do with the activation of it. The 1.6L ZM-family engines also have VTCS (since 1999) and have had no problems like that on the 2.0L.

There's something else there... and the 1.8L engines with the problem (far less rampant, but still exists) can't benefit from unplugging the VTCS, since the 1.8L was never equipped with it.

-Jerry

 

I just unplugged the damn vacuum line into the solenoid, and the irritating rattle is gone. So how can it not be the plates if the rattle is gone when I disconenct it? And if you unplug the hose, and not the electrical connection you get no engine codes. Its great, and I like my car a lot more now, that it don't have the ghetto rattle.

 

How can it be the plates if I don't have them? How can it be the plates if the 1.6L with the same system doesn't have the rattle? How can it be the plates if the problem isn't uniform with all 2.0L Protege sedans and Protege5's?

I'm not being rude or anything, but I am just not convinced it is the VTCS system that's causing it. The 1.8L and 2.0L engines have the problem, and VTCS is not equipped on both of them. VTCS is equipped on the 1.6L and 2.0L, but only one of those engines have the problem.

-Jerry

 

Its not the same rattle dude. Mine didn't go away when I put on my Injen cai, and I never had a ticking sound. Just that irritating rattle. And when I render the vtcs plates inoperable the rattle is gone. So, I'm not being rude either, but I'm pretty sure this type of rattle is related to only th 2.0L cars like my p5. Dunno, I mean I'm not a rocket scientist or anything, but its seems pretty logical to me.

 

yeah...... maybe there are two different rattles. it's possible. heck.... you can make tons of things rattle.

 

If it is a problem with the VTCS system, then why are not ALL Protege 2.0L sedans and P5's affected?? I know that my Pro does NOT have the engine rattle and I know that some other people don't as well.

BTW, does anybody have the mp3 sound file of the death rattle? I went to the link that somebody had posted before and it worked, but now when I follow that link the file is gone.
Thanks in advance.

 

I fortunatly don't know what rattle you guys are experiencing, I have a Canadian '99 Protege LX-T with the 1.8L (all LXs had the 1.8L).
Now my car has the VTCS system, without the dual catalytic converter setup(non ULEV), so I'm guessing we Canadians got a pretty good deal. I'm thinking Jerry might be on to something. The fact that some people don't have the same problem could be regional related too, say like living by the ocean where the air is moister<-(is that a word?) than in Arizona. Maybe the temerature of Cali in July vs. Michigan in January!

 

Well. I have been to both extremes and it still has the problem. Both high altitude desert and low altitude coastal (its easier to do this when you live in Texas). It was definitely more noticable in the desert but it was also a hell of a lot colder (when I went) than it gets down here in Houston. When I talked to the Mazda rep on the phone they said they revised the operation of the VTCS system when they were making the 2.0L ULEV compliant. I was told they were having trouble getting rid of the rattle while maintaining compliance. I still don't understand the people that are not noticing this rattle. I went to the dealership and complained and we went and looked at 3 seperate 2.0L cars and they all had it. Maybe you guys should turn down your stereos?

 

Several olde tricks from the How-2-Sell-Cars-Manual:

1) Warm up the car and let idle for a few minutes before customer drives it; use idle time to find a dealer plate. 2) Demonstrate the sound system & other bells&whistles during the first part of the test drive. 3) Talk up your customers, to "qualify" them [job, income, marital status, etc.]. Altogether, distract distract distract.

NewCarSmell also impairs hearing.

 

Amen to that. I don't believe I have ever seen a salesman that hasn't done that. My advice to avoid conflict: Ask to test drive another one afterwards and start it yourself. And the other part of course. Turn the air conditioner, stereo, and any other noise generating items off when you drive it. On the other hand I did all this and still missed the rattle and that annoying noise it makes when you drive it in reverse until I was doing my delivery inspection (I got my car straight off the truck). We went and drove a P5 and an ES off the lot from a cold start and they both did it so I went ahead and took delivery anyway.

So that is 5 cars other than mine and they all had the rattle.