My 06 Z has been pinging(valve knock) since I got it used. I thought it would be gone after the new engine was put in, but it did not. Been changing different gas station, octane booster...still there.

Today, finally gave up and went to get 10 gallons of 100 octane gas. It's gone..no more ping, feel a bit more power. Just wondering, will the engine ping again after I switch back to the regular gas?

 

holy cow...how much did 10 gallons of that stuff run you?!

I'd say it's going to come back, don't see why it wouldn't...but then again I don't see why it would in the first place. What kind of mods are done? Stock tune? Advanced timing? Running lean? Under what conditions does it knock?

and you're saying this is valve noise? like, not detonation/pre-ignition?

 

6 dollar a gallon...no lunch for me the rest of the week

I bought the car used, and it looks like stock. I have not done any mod to it yet. Took it to the dealer, and they told me it's the valve knock. I was wondering if the car had it's ECU refresh by the last owner. Can the dealer refresh it back to factory spec?

 

Pretty sure the dealer can't flash it back to stock. Got any friends or members nearby that could you could swap ECU's with for a day? I wouldn't think someone would flash the ecu without doing any other mods as well...Unless maybe they removed all other mods before selling it to you?

Could it possibly be timing components making noise (prolly not since it's relatively low mileage)?
How loud is the noise/what does it sound like?
What area of the engine is it coming from?
Could the valve clearance be out of spec...like too much space between the cam lobe and lifter (needing to be shimmed)?

If it's "valve knock" or some sort of valve train noise, I wouldn't think fuel would affect it. Did the dealer define what they meant by "valve knock?" I'm thinking either it was pre-ignition and the higher octane helped, or if it is something else, it was just a coincidence that the fuel helped.

It might be worth your time to post a vid of the noise.

 

I think I might got confused. The dealer told me the engine was knocking, and I had been reading "Valve knock" in other threads. Have to spend time to get all the terms right. I think it's just the detonation(engine knock). It only comes out from 2~3K rpm, and above 6K rpm. It sounds like jiggling keys.

I'll enjoy my "lunch money" for next few days, and see if the the noise will come back after I put in the normal gas. If it does, I'll take a video, and take it to dealer and ask if they can figure out.

 

Unfortunately current US Premiums may not meet the gasoline quality used to deisign and program engines in Japan.

The pump octane number decals are selected by the marketing department and may not always be true when the gasoline actually gets to your tank. Probably close to true the day gasoline was made at refinery but lots of time and problems occur along the way.

Sometimes a few gallons of 100+ is just enough to straighten pump premium out. You will have to incrementally test to find the lowest cost solution.

 

seems to me like that would be a huge pain in the butt every time you filled up.

What if you just dumped a thing of octane booster once in a while? I know it may not be the recommended solution, but it would be alot easier than having to buy two different fuel grades each time you fill up.

and yeah, it makes alot more sense that it is detonation if the 100octane is what's making the difference.

 

Not normal, definitely NOT normal. I run my 'O4 Touring Coupe on regular, and
it doesn't ping, diesel, or NOTHIN'! I guess I bought a WINNER of a Zed!!!!!!!!!!
(NO feathering, either!!!). I'M in L-U-V, guys!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
$3.39/gal.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

it doesn't diesel? wtf does that mean?

 

 

 

I wonder if he's referring to run-away detonation that can happen in older diesel cars. It's like the car will keep revving even after you've come off of the throttle due to compression ignition over and over.

I haven't heard of this happening with a modern car.

 

Neither have I. Never on a car with Fuel Injection, and I don't see too many new cars with Carbs these days. He's probably referring to something most people never see, the engine runs on for awhile after you shut off the key.

It used to be commonly used when referring to a car that ran on (roughly) after you turned off the key, it would continue to turn over for several seconds, usually because the carb didn't stop giving it gas/air for a few seconds, and esp. if the engine ran really hot or lean, timing was off, etc. Then the fuel would burn w/o the ignition spark for several more seconds.

Your car had to really be running like crap, or be heavily carbon'd up inside, or the carb was messed up badly, timing was way off, whenever I heard that in a car the only thing that came to mind was "what a POS...go tune that car".

 

If you're pinging, then you're detonating. Not good on the pistons, rods, or bearings. You need a re-tune. Consult II or Cipher can retard timing up to 2 degrees on the stock ecu.

 

It's back....damn. Took it to the dealer this morning, and the master tech told me there is nothing he can do. The tech adviser advised me to flush the injectors. Is that one of possible solutions? I'll try to clean the MAF , reset the ECU tomorrow. If it still not improve, I am thinking to get Cobb AccessPort.

 

Dieseling is engine run-on after you turn the car off due to the fuel igniting without a spark.

Used to get that every so often in my 73 Mustang.

 

just proves he knows nothing about the BS he is spewing. but whatever, he wants to run a low grade on his car so be it. when he has to go to the dealer and they find out he ran nothing but 89 octane in it, it will suck to be him if he has a problem related to the fuel or engine system.

 

What happens when you BLINDLY put fuel in a vehicle without analysing it before hand. You are at the mercy of the refiner, the pipe line transporter, the tank farm, and the service station.
The octane is only tested weeks before pumping by the refiner. You never know what the tank farm does in filling up their tanks from multiple pipeline loads, nor how each load interreacts with time.

Some tank farms have been caugt using for ethanol blend ONLY gasoline without the ethanol when they run out or just shorting the E10 to E03 thus dropping octane 2 points to save money.

Why the stickers say " may contain up to 10% Ethanol" NOT MUST CONTAIN TO MEET octane sticker.

Have been warning buyers that bad gasoline may be 2-3 points lower in octane than sticker promotes for above reason and may change tankfuls to tankful.

The easiest way is to see if 5-10 gallons of racing fuel stops the pinging, then you know the gasoline is substanard to that used to test the engines in Japan!

You cannot do anything about it other than fix the fuel you buy with racing fuels................as the octane tests don't really apply to modern engines.