2006 GP pinging on moderate acceleration

**premieregp** · 09-26-2018

Hello all, my 2006GP (NA)has been experiencing a pinging noise. This happens when going up an incline or taking off from a stop sign or light. It only does it when giving it a lot of gas and only does it when the engine is warmed up to operating temperature. The car does not ping in neutral or park. It does not overheat. All summer I've been using premium Shell gas on the advise of my mechanic to stop the pinging.. My mechanic has changed the spark plugs (AC Delco iridium), wires (Parts Master), and the thermostat. There are no codes. The car does not hesitate. It will start to ping if I accelerate quickly but only on the initial take off. It will only ping for 2 or 3 seconds even if I keep my foot on the gas pedal and continue to accelerate to high speeds. It's a slight to moderate pinging but still noticeable and annoying.
Additional info in case it matters,the main fuel line from the fire wall to the fuel regulator was changed along with the vapour line right next to it. Fuel pressure is at 65PSI. Oil changed June 2018 non Fram oil filter, K&N air filter also in June 2018.
My mechanic can not figure out why it's pinging. Any help would be greatly appreciated.
Thanks
Jess

**Mitch R** · 09-26-2018

I don't suppose you have access to a scanner? That's always a good way of figuring this kind of stuff out. I would be surprised if this pinging you are hearing is engine knock, as typically you cannot hear it if your engine is knocking because the computer pulls timing to make it stop and it reacts far quicker than we can hear. Personally I'd be inclined to look towards mechanical causes. Something is loose somewhere.

**premieregp** · 09-26-2018

The car was live scanned and everything was normal. I'll have to speak to my mechanic to check for anything loose. Anything specific he should check for?

**Mitch R** · 09-26-2018

How loud is this sound? If it was live scanned and confirmed its not knocking and everything else checked out I don't think I would be overly concerned. By your own account it drives perfect with the exception of the noise it makes. Personally, I don't know how much money I would spend on this noise, especially since you aren't doing the work yourself and labor gets expensive quick especially when neither you nor the mechanic knows what's wrong. Without actually hearing the sound its hard to take a guess as to what it might be. Your mechanic has actually heard the sound and can't tell either. At this point you are taking shots in the dark.

**cheatah faheatah** · 09-26-2018

Same car here. I also get something that sounds like 1980's ping. Heavy throttle / short duration. Members here swear you can't hear knock, I'm not so sure ??? [subscribed & watching]

**premieregp** · 09-27-2018

Cheatah does your car ping only when it's warmed up or does it ping also when the engine is cold?

**premieregp** · 09-27-2018

Cheatah does your car start to ping when accelerating only when the car is warmed up or does it do it even when you accelerate with a cold car?

**cheatah faheatah** · 09-27-2018

Originally Posted by premieregp

Cheatah does your car start to ping when accelerating only when the car is warmed up or does it do it even when you accelerate with a cold car?

Both, worse when cold. It's better if I put mid-grade gas in. NO way am I paying 50 cents more per gallon for "super". $ 2.84 for low grade at the moment. I wonder what the formula is to swap that from USD/Gal to CD/ltr ...

. I'm getting a headache just thinking about it.

**premieregp** · 09-28-2018

Mine doesn't ping when the engine is cold, only when warmed up. Super grade gas is $1.59 per litre here and regular grade is $1.39. I put super and it pings less but still pings. I took the car to another mechanic yesterday and he said it could be the plugs. The plugs on the car were changed only 3000 kms ago. Could they go bad already?

**premieregp** · 09-28-2018

Last year when the mechanic replaced the spark plugs all 3 of the rear plugs snapped in half while he was removing them. If there are tiny pieces of the old plug in there could it cause the car to ping when the car is warmed up?

**Mitch R** · 09-28-2018

It would've destroyed the engine by now. Likely the ceramic ends busted, not the metal tips so it's very unlikely that any got in the motor. The only way I can think of that would cause you to be able to hear engine knock is if the knock sensor is bad. If the engine is knocking and the pcm doesn't know it because it's not being reported, then it would just keep knocking until engine conditions changed. I don't think I've ever heard of one going bad though.

**Scottydoggs** · 09-28-2018

check the belt pulleys yet? never know.

**BillBoost37** · 09-28-2018

Interestingly enough the NA cars have a ton of timing and I always ran 93 octane in order to keep mine happy as possible. I also had the ability to program it and remove a touch of timing.

When the car is cold, there are fuel adders and timing is also modified. That could account for you not hearing the sound when cold. The difference between cheetah and you could be climate, altitude etc, so while some things are similar others could be a factor of where you both live.

Your mention of the fuel change helping the issue would back up my theory that it's pcm programming related. Unfortunately GM is never going to tweak your timing a little to help with the issue.

**Bronco Boy** · 09-28-2018

Many many years ago, when I had my Bronco (1985, 5.0 EFI), and I put 87 octane fuel in, it pinged a bit. 91 octane was fine. I used to fill up in the US, and had to use 92 or higher octane to keep the ping away. A short time later, I replaced the timing chain, and voila, the ping was completely gone. I've always assumed that it was the stretched timing chain causing the ping.

**jamesc43** · 09-28-2018

Personally, I would change brands of gas. I’ve never been happy with Shell’s brand of gas.

**premieregp** · 10-09-2018

I had the MAF sensor cleaned with CRC MAF sensor cleaner, the TB plate cleaned with brake cleaner, removed the K & N air filter, and added 2 bottles of Lucas Fuel treatment to 2 tanks of gas yet the pinging is still there. I noticed that when I turn the heat on the pinging stops.

**cheatah faheatah** · 10-09-2018

Strange ... smh.

**premieregp** · 10-24-2018

Update: Another garage scanned the car again. He said the crank position sensor was reading too lean at minus 5 so he reset it. Two coil packs (6 and 3) and (1 and 4) were causing a slight misfire, although the car was not shaking or it was not noticeable. So he replaced those two coil packs. He also removed the EGR valve, which was not all that dirty. He cleaned it. He checked the flywheel as well. I know most people don't usually post back when their issues are resolved but I wanted to in case someone has the same problems and are looking for answers and I know I would appreciate it.

**cheatah faheatah** · 10-24-2018

Originally Posted by premieregp

Update: Another garage scanned the car again. He said the crank position sensor was reading too lean at minus 5 so he reset it. Two coil packs (6 and 3) and (1 and 4) were causing a slight misfire, although the car was not shaking or it was not noticeable. So he replaced those two coil packs. He also removed the EGR valve, which was not all that dirty. He cleaned it. He checked the flywheel as well. I know most people don't usually post back when their issues are resolved but I wanted to in case someone has the same problems and are looking for answers and I know I would appreciate it.

Soooo ..... pinging no more ?

**premieregp** · 10-25-2018

Actually the garage ordered and replaced all three coil packs not just 2. And the MAF sensor and assembly were replaced as well. Too many parts replaced, was hard to keep track.
I don't notice anymore pinging.