My car "pings" like a "sonofabitch" if I give it gas while in D "Drive" at low speeds ( 50kph or less ) I have taken to using the J gate and when driving slowly I keep it in 3 or 4 and this fixes the issue. I use local "premium" fuel which is "supposed to be" 91 octane. Has anybody used any of the octane boosters that are on the market. I know that some are just "snake oil".... nbut the local 'hot rod/custom" guys swear by some of the others

 

I have heard that additives with "Techron" can help up the octane and clean up your engine. I assume you are not getting any diagnostic codes or MIL ? Does it make any difference if you try it in "sport mode" ?

 

Even if your fuel was actually 87 octane and not 91, it would not perform or sound as described. The 4.2 engine is very tolerant of such things.

Look elsewhere, particularly plugged cat converters..

 

+1 on what Mikey put.

 

if it is not the cats, which it could be at that mileage, you might be experiencing piston slap where the skirt of the piston is contacting the cylinder walls. it shows itself under low RPM loaded conditions. very rare though, usually the engine shows some other signs of wear long before this symptom appears.

 

don't think the cats are plugged because power output is unaffected and fuel economy is excellent. I think that I would recognise piston slap as well. This is almost surely ping/pre-detonation. Sport mode does make a difference as well but I figured that was probably because the trans was not even shifting into 6th gear at low speed

 

Are you sure you are hearing pinging or is it a belt slapping? I would think if the car is pinging so bad the knock sensors would pick it up.

 

Check the fuel trims. Likely you have air leaks and fuel trims in the high teens. A code triggers at +25. No happiness unless you have trims in the low single digits.

I had the same thing until I went around the heads and replaced all o-rings, VVT seals, dip stick o-ring, etc. Symptom is low rpm, going uphill (low rpm, high load) with some load, but not enough to downshift to the lower gear.

Best of luck, keep us posted.

 

+1 fmertz

running too rich could definitely cause this and the ECM cannot retard the timing enough to stop pinging in such a situation otherwise the engine would stop running.

How is your fuel economy, highway speed, long trips? might give an indication.

a simple test might be to block the breather port attachment on the intake runner take a drive and see if the problem stops. you will not get excess air from any crankcase leaks.

 

Again, this points away from detonation.

 

I think you mean "running too lean"

 

That's it all right. My fuel economy is IMO excellent . about 9L/100km ( over 30 miles per imp gallon ) at highway speed of about 115 kph ( 70ish mph ) Power output is great. My old 67 cougar with a 289 high output V8 and my old 71 Mini-Cooper S were the same around town if I didn't run 98-100 octane fuel ...which was readily available back then. I'll have a look for air leaks and research this fuel trim business. Thanks all

 

thanks for catching that, meant one thing, typed the opposite. for others the reason that lean is what should have been typed is that the air leakage leans out the mixture and registers at the O2 sensors as additional oxygen hence too lean.

 

I am surprised that you do not have any codes. The direction I would take at this point is to take fuel trim readings and see what comes up to be sure the engine is operating properly.

The thing that I do not get is that it does it in “D” and not in the manual mode, unless the transmission is not seeing that it needs to downshift under load and that would lead me to the transmission / ECM modules not sending the command to shift. This would put the engine into a heavy load and could cause the pining. I am still surprised the knock sensors did not see the problem.

When you are shifting in manual mode do you just put the shifter in 3 or 4 and just drive or do you move it up and down as you drive? Also you made no mention of 5th gear does it cause a problem?

 

Short version: Get an ELM327 from eBay/Amazon (a few $) and a corresponding phone app (Torque Pro, etc). This will let you read all standard OBDII data, including fuel trims. Build a screen that shows short term and long term fuel trims, both for the left and right side. Long term trims at idle eventually need to be in the low single digits (say, less that 5%).

The "fix" is to get an o-ring kit from Harbor freight, and, for every connection to the cylinder heads, pop it off (Norma, just squeeze and pull) and replace ALL o-rings. Also replace the VVT seals (if you see oil, air is likely going in). eBay is great for these seals. Also do the dip stick. As you do this, you will likely be rewarded by negative short term trims on your next trip. Over time, these negative short term trims will lower your long term trims a bit a time, as air leaks are getting plugged.

Best of luck, keep us posted.

 

The codes come on at 25. Anything lower is considered managed by the ECU and no code comes up.

What he likely means (I did the same) is that in order to avoid this low rpm/high load situation, one can downshift manually to the lower gear, so it is less load, higher rpm, and the ping goes away...

 

I hope he posts whet he finds to be the problem. I am just surprised with no lean, rich or knock codes.

 

Sorry I did not see anything about a code on the post or did I miss it. I would suggest driving the car in “D” with the OBDII code reader connected and see what comes up. Most of the time the code reader will capture any abnormalities.

 

Thanks for all the replies. My son in law has a scanner and may be able to read all this stuff. In answer to the question about shifting...I basically shift down as if I was drving a standard to keep the revs up a bit