Hey all, hey my speed6 is making a knocking noise during acceleration at normal speeds. It happens in all gears, worst of all it's not repeatable so Mazda service will not help. They tell me to bring it back when it's making the noise? but since it only happens once in awhile........it will be my luck that the damm thing will break after warranty is expired. This only started to happen after my re-flash and the noise seems to be coming from either the engine or tranny and it almost sounds like the valves are knocking bad

 

Couple questions for you:

1. When was the last time you filled up with gas, did you remember to put in the top grade?

2. When was the last time you changed the oil, what weight of oil did you use?

3. How many miles?

4. How long after the reflash did it start?

 

OK, It first started about 2 weeks after reflash, oil was fine and since I'm in Calif 91 premuim is all we get (I thought it was the gas but I have tried other brands and get the same result). Seems to happen every 3 weeks, I have been trying different things to repeat but no luck. It seems when I'm not trying it happens, worse is that it has happen when I needed to accelerate. It almost feels like it's choking or misfiring

 

Sounds like you're getting knock. My understanding is that the reflash simply tells the the knock sensor to wait longer before kicking in and cutting the throttle down to 33%. I guess the only way to prevent knock in the first place is to find 93 octane, or use an octane booster. It would makes sense that it happens when you're trying to accelerate, as well as the sudden decelleration when the knock sensor cuts the throttle. I've read that the knock sensors are extremely sensitive and fast, and the system is able to cut the throttle down to 33% before the impending knock occurs in order to prevent damage to the engine. What does everyone in Cali do for Premium in cars that recommend 93 octane?

Regards,

Keith

 

Well to answer your question about octane here in Calif, it seems 91 octane is it ! I dont know of any other cars that require 93 octane other than the Speed6. Now, I have my car in service again but this time I got lucky and had the tech go for a ride. Yes!!! the car did it's valve knocking during test drive, now after 1 full day of troubleshooting the tech is STUMPED and so is the Mazda Tech line. It seems my car is the only one with this problem and no fix is available, hell they dont even know what it is wrong with the car and after several different procedures. The car is still making it's noise's (the tech looks beat) I love my car but I'm not to sure whats going to happen next?

 

This is quite a stumper. Intermittent problems are always the worst to troubleshoot. Even though the manual doesn't recommend fuel additives, you could try simply adding a bottle of octane booster. I live in CA too, so I have to run my speed 6 on 91, but it gives me no problems. Sounds like a knock, not valve noise, as valve noise should be more consistant. Sounds like something occasionally is causing a too lean or too rich condition, leading to your knock. You could be occasionally developing a hot-spot on the cylinder wall or one of the valves due to a problem with the cylinder wall or valves, or due to carbon buildup. This is just all speculation, though, I'd have to see it. Before it's all said and done, you may have a new engine or car for free though.

 

Man I'm gonna get heat for this 1...my RX-8 freekin knocked just like yours by the sound of it. Tried different gasses, a few addditives but always seemed to be there on occasion. I tried 89 octane fuel <<<<when the price of gas started to skyrocket>>> & I never got another knock. Not 1. Put 58k on it & in the RX forums you'll see big debates on octanes & owners manuals recommendations but it worked for me & I was truly amazed. Never mentioned it to anybody <<hey its a sports car gotta put the best in it lol>> Course I spill the beans now after I traded it in for an 07 mazda6 hehe.

 

Did the dealership ever actually fix the problem? I've had my speed6 since aug and it does the same thing. It seems to like Cheveron fuel better than other brands, but of course the dealership can't duplicate the problem so I must be crazy. I seem to notice it most often at about 3000rpm under acceleration. I love this car, but it definetly has some problems.

 

A semi-related question: What's a "reflash"? Pardon the thread hijacking...

David

 

A reflash is just a reprogramming of the computer - they erase the program on the computer and reload the factory programming / settings.

This may include changes they deemed necessary to the program, i.e. retarding timing to reduce knocking.