I've read through some of the older thread trying to find what would cause a knock in the Pro5's and found, basically, crappy gas...

I have yet to see anyone complain about it happening constantly, less I missed a thread.

I'm using 87 (tried 6 different manufacturer's on dealer's recommendation) Still have the same problem.

I tried 89, again due to dealer, and still and same problem... though the knock/pinging is less pronounced.

They checked the timing, everything's on point.

Last thing I heard was what's your number, we'll call you back. It's been about a week.

This problem has existed for over 4k miles....Can or will this cause any problems down the line?



-All stock, manual.

 

I'm having the same problem! I've switched to 93 octane, and seems to have cured the problem, although it bothers me that this is happening, as the manual specifically states that we are to use regular gas.

Does anyone have any idea what could be causing this? I'd take it to the dealer, but this is my only car, and I can't afford to be without it for however long it would take them to diagnose the problem.

 

Maybe a bad spark plug, or incorrect plugs.

Try changing your plugs and using OEM spec ones. Nothing is foolproof - spark plugs can go bad before the 30,000 mile recommended change interval.

Also inspect your ignition wires, and make sure everything looks to be in okay shape - nothing torn or worn, no arcing between wires, etc (hint - run the car in the dark to check for any arcs between wires - only way you'll see it).

Other than that, keep bugging the dealer - your car is under warranty, and should be fixed.

 

I haven't pulled the plugs, but I don't think that is the problem; there is no miss or hesitation, all the wires are fully seated, there is no arcing between wires. I know it's not the wrong plugs becuase they've never been changed (the car doesn't even have 10,000 miles on it yet).

Additionally, the problem goes away entirely when I use premium gas. Maybe I'm wrong, but I don't think that would happen if there was a problem with the plugs.

I'll pull the plugs this weekend, but I really don't think that's it. Any other suggestions?

 

Exmiatman,

You dealer should provide a rental during the time they need to repair the car.

I received a call back today from my own dealer... they have not had this problem reported with any other vehicle out there. In short, they don't know what's causing it since the last time they took a look. I was asked to bring it by next week. I'll keep you posted...

 

Like I said, both the plugs and the plug wires have less than 10,000 miles on them. I'm going to pull the plugs this weekend, but I don't know about replacing the wires. There not the kind I'm used to seeing (they're smaller and have small black boxes attached to each one). What would they cost to replace? Something tells me they're evry expensive.

I went looking for a bottle of Techron last night, but the store I went to was out. I'll find that this weekend too. One bottle of cleaner (STP brand) has already been run through the system about 1,000 miles ago.

I did some research last night, and read that a faulty EGR valve can cause spark knock. Where is the EGR valve? How do you check it?

Unzipped, I'm really anxious to hear what your dealer has to say. Let us know. FWIW, dealers around here aren't very liberal with their loaner cars. In fact, it's almost impossible to get one unless you drive a BMW/MB/Jag etc. But you can bet I'll try if I end up taking it to the dealer.

Until then I'm still using 93 octane.

 

Well, don't let your dealer know that if you bring the car in - the manual expressly states that any fuel additive other than those recommended by Mazda should not be used. Not sure of the warranty implications, but I wouldn't go bragging about adding detergents to your system.

I have 27,500 miles - and never had a knock or ping. I also have never used any fuel additive, and just changed my plugs (a few thousand miles before the 30,000 recommended interval).

Try changing plugs, and stop using system cleaners - 9,000 miles, and you're dumping additives into your tank? What for? All gasoline has detergents in it anyway - and with only 9,000 miles, your Pro should not need any more.

 

Why the attitude? I'm not "bragging" about adding detergents, I used them in an effort to solve a problem I'm having with my car. I'm smart enough to use one that is 02 sensor safe, and to not tell the dealer about it if I take it in. By the way, the manual also expressly states that I should be using 87 octane.

I'm apparently not alone in thinking this is a good course of action to take. Several people on this board have suggested it, as have countless people on other boards and a mechanic friend of mine. Maybe I got a tank of really bad gas, and it gummed up the works? Anyway, it's one of many things I wouldn't normally do that I am now forced to try becuase of this problem--much like changing plugs at 9,000 miles.

I'm glad your car doesn't knock, but my car does. Others here have the same problem. What we don't need is someone attempting to belittle our efforts to address this issue in a logical manner. Next time, check the 'tude at the door, please.

 

Dude - in no way was I trying to give you crap or an "attitude". Sorry if you took the use of the word "bragging" the wrong way - I was only trying to give you a heads up on what NOT to tell the dealer - that's all.

I wasn't trying to belittle anyone's efforts to solve the knocking/pinging issue - I was trying to help. I'd hate to see anyone walk into the dealer, explain all the methods they've used to cure the knock themselves, only to be told that those methods were incorrect and that the repair will not be warranty covered. Some of these guys try to be real sharks, and attempt to use any possible reason to deny a warranty repair.

It was also unclear whether you first used the additive at 9,000 miles to try to cure the problem, or if you just used it because you thought it would be a good idea. My impression was the latter - that you dumped in the additive as a "preventative maintenance" kind of thing, and I was suggesting that the use of it may have (somehow?) caused the problem to begin with. I didn't realize that you didn't use the stuff until you started having a knock/ping issue.

Looks like we just misunderstood one another - so I extend my cyber-handshake to you. I was truly only trying to help out in whatever way I can - not give you a hard time.

~HH

 

Cyber-handshake accepted. Yeah, I didn't even think about an additive until it started knocking.

Unfortunately, I'm well aware of some dealers' shark-like ways. That's why I'm trying to get a better idea of what's going on before I take it in for any work.

My tank is about empty, so I'm going to put a few bucks of 89 octane in it and see what happens. I'll keep everyone updated.

 

What exactly does a knock/pinging sound like? Is it loud, meaning can you hear it while you are driving? at idle? when the hood is open? Im not sure if I ever heard a car knocking or pinging... Where does the sound come from?

 

Mine sounds like some shaking a bag of large ball bearings or marbles. It only does it when the engine is under load, so it doesn't do it at idle or when revving the engine while in park or neutral. It is most noticeable when accelerating in top gear. If the knock isn't too severe, it can be mistaken for a rattle in the engine compartment (or even the dash). It usually doesn't happen when it's cold out--I bought my car last September, and didn't hear any knock until this spring.

 

This isnt the same noise as if you try to take off in 2nd or 3rd gear is it? Does your car shake/rattle?

 

No,that's the sound of your engine/transmission contemplating and early death.

This is a metallic rattling noise; there is no vibration associated with it.

 

After a bottle of injector cleaner and several tanks of premium, I filled up with a few dollars of regular last night. So far so good, although I'm sure there was some premium left in the tank. I'll let you know what happens.