This is my second F150 4.6. My last one was a 99, this one is a 98. I've also had a lot of experience with others when I worked for a utility company with a fleet of them.

They all seem to detonate a lot. I don't worry too much about it because my 99 made it to 213k and my 98 has 126k without any detonation-related problems, but I wondered if it was a fixable thing or if I should just ignore it and put my foot down.

My 95 detonated a lot too... but it was a powerstroke so that was a good thing

 

No they don't .. Unless there's a problem.. What are you doing to the trucks to cause this?

 

It's actually pre-detonation. You have a timing problem. Your engine is firing before the piston reaches top dead center. It may be caused by poor fuel. Try running a higher octane. Continual predetonation hammers the cylinder, piston and rings rods and crankshaft.

 

my truck does it when i put crappy gas in. try putting in some premium

 

There is a difference between Pinging and Detonation.
Normal ignition alway begins before top dead center. It has to.
This is a complex subject that needs to be looked at in depth to get all the understanding needed.
I believe you are refering to Ping and not detonation.
Ping is early ignition for the "charge quality" that exists.
This is important. If the EGR is leaking, the A/F mix becomes to lean 'quickening' fame propagation. This will result in Ping.
Fuel octane to low also quickens flame propagation for the same end result.
Compression to high for the fuel octane also results in the same.
.
Detonation is the "uncontrolled" ignition of the charge.
This can be caused by excess oil in the mix, low octane, timing to far advanced, hot spots in the chamber and even a ping condition that turns into detonation after going on too long a time heating piston tops, valve heads etc. until hot enough to ignite the charge before the plug normally fires.
This condition is what causes run-on after the ignition is shut off and bangs and hammers until cooled off enough to stop ignition.

 

Well, I sure hope so. It has to.

 

Heck no. I'm not going to mask a problem by spending more on fuel.

The chamber design, cam timing, static compression, and modern fuel mapping in this application means that anything more than 87 is completely unnecessary.

 

Agreed. I should have been more specific in my knowledge. Yes, detonation can be the cause of ping, but ping doesn't always come from detonation... but, Since I am dealing with a stock engine, with a stock timing curve, (verified by real-time datalogging) detonation is a logical assumption.

But, for the sake of this discussion...

Why have all of my 4.6s had ping?

... and...
uh... driving them empty, anywhere from 1/8 - full throttle, 87 octane, and it happened in approximately 55 F150s ranging from 98-2002, so I know its not a random screw-up in my particular truck, its a pandemic across the board.

Maybe I should ask you... what are you doing to your truck to NOT have it happen

 

My 02 does not have any noticable ping under even heavy towing conditions but then being older it may have some I can't hear.
Not enough to be of concern if it can't be heard.
Most of the time you will find that modern motors will exibit some because the timing curve runs as advanced as possible to get as much low end torque as possible as well as fuel mileage. I call this compressed timing.
I live on a steep hill where the road goes up and hear 8 out of every 10 vehichles ping while pulling the hill no matter if car or truck. Some bang pretty hard.

 

Well, uhhh... -

Not this board. Where does the fleet fuel up? In the yard or Gas card?

Between my daughter and I - had two 98's, a 4.2, 5.4 and 01 5.4L. The 98 V8 has 260,000. I have yet to hear a Ford engine ping or pre-detinate. I frequent the engines forum quite a bit here and haven't come across those kind of problems all that much. It's not unheard of, - just not that common.

You have an epedemic going on. Somethings up with the petrol, has to be IMO.

 

Each truck had a Visa; so anywhere in the tri-state area. Any brand, and location, anywhere.