Driving around the city Saturday with the windows open, heard my engine pinging like crazy on gentle accelerations and light throttle changes @ 30-35 mph. This was the first time I had the windows open driving around town.

Luckily some searching on the forum resulted in the TSB JTB00064 for my VIN range, and that's covered under my warranty. Dealer is going to do that update this week.

Hopefully that will fix it. I can't believe that the knock sensor won't dial the timing back when it occurs. Sounded like a popcorn maker under my hood.

 

Hey let us know what happened sounds like this could help a lot of people.

 

What octane level of fuel are you using?

 

93, the highest I can get at the pumps. I'm sure the 10% ethanol does not help anything, but always try to use a top tier gasoline.

 

That's very strange. Even if the knock sensor was dead as a door nail there should be no detonation on 91 or higher (?).

'93 octane' is '93 octane', irrespective of the fuel blend. Pure ethanol is actually 99 AKI octane so the E10 is not the culprit.

 

Perhaps... post #4 in here has the TSBs for the pinging on this VIN range: https://www.jaguarforums.com/forum/x...hrottle-46957/

It could be these engines have pistons or heads that accumulate carbon on sharp edges. The dealer was trying to sell me on "injector cleaning" but I know that wouldn't do anything. If the injectors were dirty I'd have long term fuel trims indicating the PCM trying to compensate.

 

Or the maps in the ecm might not have allowed enough room for drift. In other words, the fueling or spark maps are a bit agressive. So the reflash would change to something with more margin for boundary conditions.

 

Was thinking about it last night on my drive home, I'll bet anything that had I turned on the a/c the pinging would have stopped.

Since I was crawling around town, mostly stopped at lights, windows open and climate control off, the radiator fan wouldn't run until the coolant got very hot. With a/c on the cooling fan runs on (at least) low speed, which would have broguht the engine temp back down and probably stopped all pinging.

If our temperature gauges weren't just dummy gauges, we could probably see this. In my last car, if I idled around town the gauge would creep up to the 3/4 mark before the fans kicked on, but turning on the a/c ran the fans and kept it dead center.

Last night I drove 30 miles on the interstate (a/c off), got off and drove about 2 miles through the city, no pinging at all. Only happened when I did extended city driving and let the engine heat soak.

 

On my way to the dealer yesterday afternoon I got off the interstate and the engine did do its light pinging as I drove through town, so at least it's reproducible. The dealer was nice enough to do the flash while I waited, so 45 minutes later my car was ready. Seems to be running very well now! No more ping, and it also seems to be accelerating smoother. It feels like the 1-2 shift is a lot better, so maybe the flash updated some other parameters as well. Either way, I'm happy

Dealer still says the 4.2L has issues with Ethanol, which I may or may not believe. He suggests if there's any more pinging I run Techron or its equivalent through a tank of gas. May do that either way, Techron seems to be good stuff.

 

Thanks for the update.

Let us know if there's any changes.