I have a 97 F250 H/D with a 460ci gas motor. It has about 28,000 on it. The other day I did something I don't ussually do. I was getting on the highway and put the peddle to the floor. Everything was fine until it was about to go into the next gear and it sounded like I had marbles under my hood. It hit the next gear and it went away. Any ideas?

 

You mean marbles, like shooters and cat's eyes?

Could it have been pinging or spark plug detonation?

What grade of gas do you use?

Is your "Check Engine" light on?

WOW! I just got promoted to a "Senior Member" !!!

 

spark knock. Heat and low octane don't mix

 

Hey congats. Lolololo. Yup Pinging. I use premium and have no Check engine light on.

 

A couple of years ago I had some pinging that eventually caused the CEL to go on. Had the (I can't remember what you call it - somebody help me out, has lots of little nooks and crannies that need to be cleaned...) cleaned and the pinging went away.

I will try to update this post with the code and the name of the part that needed cleaning tomorrow.

Long term, my understanding is that it can cause unwanted damage if not resolved.

Just in case I carry a little blue bottle of "liquid octane" - $1.25 at Autozone. Only needed it once, must have had a bad tank of gas. Add to gas tank and knock goes away for several days.

 

either use premium or mix in some acetone to raise the octane level of ur fuel. acetone method is cheaper just is a hassle premixing and measuring it. about 1oz for 10 gallons

 

Pinging for sure... Almost 10 year old engine with only 28k on it.... Well, it's probably all clogged with carbon buildup in the EGR and cylinders from it's limited use and probably short trip use it's whole life... I'll bet it has probably not reached full operating temp for more then an hour at any one time...

Could be a 'timing' issue as well... But, if you are already using premium fuel (92 octane) and it's still pinging under load then it's deeper then that. You should only need regular (87 octane) for that engine.

I think the thing just needs to be run and allowed to heat up to 'burn' away all the deposits... It might be too late for that to occur naturally, but you don't want to hear the pinging for very long, because it'll damage your engine over time...

Good luck!

Mitch

 

Will acetone eat up all the rubber parts such as filler hose etc...?

 

I have been wondering that as well.

As for the engine behaviour, who knows but given its age and low mileage, I'd say a Seafoam treatment and a nice long trip are in order.

In my own experience, in my '92 which had not been driven much and semi-neglected before I bought it, it's been running better and better the more I drive it, together with some premium fuel and some non-Seafoam treatment (I'm told the Kamloops BC NAPA sells it but haven't seen it there yet.)

 

If I were you, I'd wait until the engine warmed up, then take it out on the road and floor it. Leave it on the floor until you get scared. Then stop and do it again. If that doesn't fix it, remove your spark plugs and clean them. I bet that between the both of these, it will be running great.

 

YES.
Mark, I'd Seafoam it, give it an italian tune up (as in run the **** outta it), and drive it for a while. Or just trade trucks with me. Cause I need a 460 to pull a 16' boat.

 

Clean your EGR and all EGR ports.
If your plugs are old, replace them as well.
As posted, you could also have combustion-chamber carbon buildup.

Ping = bad

I wouldn't do the Italian tune-up (driving it fast) if it pings when you do it.

 

nope. when its diluted propperly it will not. but never pour the acetone straight into the tank. its best to premix is with a 1 gallon or a 5 gallon can then pour it in.

 

Make sure that they know to pre mix it with GAS, then add it to gas tank. Some dummy might mix with water, then pour that into gas tank.

This past Spring, I watched someone in a late model Porsche Carrera, not paying attention to what they were doing, filling their gas tank with Diesel!

 

The noise you heard was valve float. The cam was spinning a little faster than the valves could return to posistion and they slapped against the cam surface.