I don't know which term is correct, but obviously I am referring to the sound that is made by the engine when accelerating under load (often uphill) at low-medium rpm. Also high rpm under very high load. Obviously this problem is magnified by pulling a trailer also.

Also in my experience with this issue I've always thought it sounds more like a chain rattling , not a "knock" or "ping". Anyone else agree?

Let's please not have someone school me on WHICH of the terms is accurate, unless it directly points at a solution.

Ok now that I've identified the issue, please offer me some advice. I am writing concerning my 07 E350 V10 work van (which I love). I have had spark knock/detonation/etc with my other Ford also (2000 Contour V6). Ever since brand new it would do it. Upon running higher octane fuel, the Contour would run smoother, no spark knock, and had a bit more power. Results were 100% double-blind repeatable.

With the van, I upgraded to 89octane and ran through 2-3 full tanks of fuel, then 93octane. My fuel economy was lowered a solid 1.5mpg. Unacceptable to go from nearly 13 down to low-11's. (To the best of my memory the detonation did cease mostly).

The van has 128K miles and only maintenance is 3oil changes since I bought it in June (every 4-5,000 miles). I NEVER buy cheap, no name fuel. Only "big oil" companies like BP, Marathon, Shell, etc.

Please advise!

 

The sound you described is probably pre-ignition, aka "spark knock" or "pinging".

How many miles are on the van? Have you ever cleaned the MAF sensor with electronics cleaner? I have had a few Fords that started pinging when the MAF was dirty. The V10 in my F350 used to ping a little under certain conditions, but after a complete tune up it hasn't come back.

128k miles...have the spark plugs ever been changed?

Also, I doubt the higher octane fuel caused your fuel economy to drop that much. More likely is the van was operated under slightly different conditions. Head wind, idling, load, etc.

 

I'll try the MAF cleaning thing and report back.
FTE posts have me scared to even touch the spark plugs. I am afraid of the thread damage issue.
And regarding the fuel economy: I burn through a full tank of fuel every 2-3 days, and for 4 months straight I was calculating the economyat every fill up. For the first few months it was almost always low-mid-12's. After my octane experiment it was high-10's - low 11's. It was 2-3 consecutive tanks that I got those results. With all that said: there are variable in my daily travels (as you mentioned) but it's usually pretty much: drive 50 miles on interstate to Orlando, drive 50miles IN Orlando, idle about a total of an hour per day, drive about 50 miles home.

Maybe I'll jump into that spark plug job this weekend. .

 

Regarding your spark plug concerns................

It's not that difficult or scary an operation although even I was highly, highly concerned of destroying my Modular Motor first time I did mine too. You'll learn so much doing it yourself the first time, each successive cylinder you tackle your confidence builds rapidly.

Follow a good practice removing and re-installing the plugs which includes using nothing but Motorcraft or Autolite plugs. Change boots as needed (or if in doubt), a dab of dielectric grease as outlined here so often and for gosh sakes BE CAREFUL removing the COP connectors---older ones can break the locking tab away, won't hold to the COP and give you a misfire. Good thing there are readily available replacement connectors for that very problem.

Another thing is plugs should be changed at 50K miles regardless what the hype says about them lasting 100K---it just ain't so!

 

I am capable and confident to do the job except for the idea of damaging threads (in such a manner that the Triton V10 is somehow more prone than other engines I've worked on.) i saw a video on the internet about a guy showing the best manner of dealing with V10 spark plug threads is to use an air impact. Theory is that the hammering is safer than a slow, strong pull. What is your experience?

I appreciate the spark plug advice (truly) but I am wondering if anyone knows of any other possible causes of the "ping" as well. Apparently not, because only two ideas so far. But nonetheless I appreciate the thoughts of anyone who hasn't spoken up yet.

I guess it's fair to say that this issue is not terribly common with other V10 owners...?

 

I've got to agree with the above posts, if the plugs haven't been changed in 100k plus, it needs to be done.

Pinging is normally a timing issue (too much advance for the fuel used) if you've run fuel conditioner that removes moisture/water (if theres a lot may take a few tanks to remove it by just running it) , then I'd say do the plugs before going further.

I believe there can be other reasons for timing to change from spec, but see how it responds to fresh plugs, map cleaning, air filter, confirming no vacuum leaks etc, before heading down that road unless you have access to diagnostic tools

 

The V10 in my 2005 Excursion is detonating under the same conditions you described. It just broke 100k miles and it's new to me so I don't know much about the maintenance history however it appears to have been very well cared for. I just put 89 octane in it yesterday and haven't driven it much but believe the detonation is less or perhaps gone.

I'm curious if the MAF or plugs helped, if not any other suggestions?

 

I just realized that my thread here needed updated. The spark knock gradually got worse over the next couple years.
My catalytic converters were bad. I paid a hillbilly shop $100, he hacked out all four and welded in straight pipes and now it runs great (although foul smelling emissions).