2005 F250 SD 5.4 auto/ k&n air flow/cat/conv.eliminated /122.K
I know this topic has already been discussed and I have never had to give it much consideration until this weekend while traveling on the turnpike.
I had cruise control set at 70 mph (legally) and was towing my boat (about 2000 lbs)
As I started on certain hills (not very big in Florida) I noticed the engine pinging. I was traveling with the O/D off. I use regular unleaded 87 octane fuel. Would increasing the octane level prevent or should I look at another cause. Any advise would be appreciated.

 

You are leaning out the engine. That noise is the pistons slapping around during predetonation. Can cause a lot of damage. A higher octane can help, but what you really need if you are going to run a CAI is a custom tune. Either an Xcal 3 or a Gryphon. That way, you know you will be running safe, plus, if you get a Gryphon, you will have the gauges to monitor temps, etc. while towing.

 

Until you get it sorted out, you need to use higher octane fuel to prevent damage.

 

higher octane fuel will help. and i agree 100% about the tuner. i would never run anything lower than mid grade fuel in a truck or v8 and such. i dont care what your owners manual says about it being able to run on it, it can still do a little bit of damage to your engine. some people get lucky and go 200,000 miles without a problem but others dont.

 

If it doesn't ping on 87, there's no reason to run any higher octane.

 

correct. May even be leaving deposits. However, you can be running lean and not hear a ping, that is way I suggest getting a custom tune. Especially when you know it is in a near lean condition and you have heard the warning from the engine.

 

Dumping higher octane fuel in the truck will eliminate the pining but that's masking not fixing the problem. Replacing the DPFE valve and cleaning out the EGR valve (and its plugged up ports) ended the pinging in my 4.6.

 

That's why I said "until it's fixed" - if you keep driving it when it's pinging, you could blow a hole in a piston or burn a valve.

I don't know if I'm gonna buy into that. I have yet to see a properly documented case where the use of high octane fuel in an engine that doesn't NEED it has caused any problems other than draining the wallet quicker. In the past, higher octane fuel usually has had more additives and actually burns cleaner. You may get SLIGHTLY better gas mileage and performance due to the knock sensor allowing for more timing advance.

 

Well, if its ever going to ping, towing up a hill in summer is going to bring it out.

IMO, your intake and exhaust mods are causing you to run a little lean. The truck probably works pretty well and gets decent mpg most of the time.

I agree a custom tune would probably cure it, but if you have no other signs of detonation, you might just try running premium when you tow.

As to other causes besides too low an octane fuel, you should search the web for descriptions of pining and detonation / pre-ignition.

If your cooling system is not working properly, that can contribute.

Basically, pockets of fuel are igniting before they are supposed to. Higher octane fuels resist pre-ignition. Anything that causes combustion chamber temps and pressures to increase can cause detonation. Lugging the motor under heavy loads greatly increases combustion chamber temps and pressures.

It can be VERY harmful to your motor in only a short time, too.

 

I had mostly stock 4.6 in my '98. Only mods were K & N filter and Cat Back Exhaust.
I was getting 'pinging' under exact same circumstances. The MAF (Mass Air Flow) sensor was dirty.
I am told the K & N flows more air and more DIRT.
Changed MAF and went back to 87, no probs.
Good luck.

 

Thanks for all the replies!
I will certainly look into having the custom tune done. Now, I am confronted with my next question, should I go ahead and purchase the tuner or take it to a shop to have it done?. There is one here in Central Fla. (Debarry) that does it but I don't know if the truck is prepared to have it done ie. plugs, and certain other setting that they have listed on their site (I believe its VMP or something like that) Again, thanks for all your imput.

 

Do a search for Justin VMP and you will find lots of reading. He frequently posts on here as well as having many customers. You will get a more accurate tune if it is done on the dyno. If you can do it, that is the best way.