1989 F250 460ci pings under load??!!

you must retard the timing or run a higher octain gas. old john

my father in law had the same problem with his motor home. I got so bad that he couldn't even get up hills out west. after every conceivable fix, by over 30 different ford dealers. Finally pulled the EGR. put in a block off plate, plug all lines. and Wham...thing flies up hills no more spark n=knock

Had the same problem, and it was the EGR valve sticking. Someone else posted that they blocked off the EGR valve to solve the problem, but that doesn't make sense to me, as the EGR allows some exhaust to be re-burned to slow down the combustion rate. Higher combustion rate = pinging, so I'm not sure why blocking off the EGR wouldn't increase the pinging.

Here's your error:

Pinging is caused by combustion too soon, which is different from what you are trying to say above. EGR gas is not very reactive but it's hot as the hubs of hell. In the area of compression-generated heat, EGR gas is just as lively as anything, plus it's got a 500 degree head start.

Mostly true but pinging is caused by the mixutre not burning but rather detonating because the mixture can auto ignite above 500 or so. Sometime EGR helps and sometimes it hurts the problem as it depends on engine. Honsent though 87 octane it to low for a big block pulling a load and cripples its potentail. I never use 87 in anything but tractors and mowers and been this way for years. Use some better fuel and dail in a little more spark and wake that engine up a bit. Octane requirement also increases with tempature so you need more octane on a hot day than cold and really low humidity increases octane requirement a bit too.

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Got it, thanks. So when my EGR valve was sticking and I was getting pinging, I had assumed that not enough EG was getting through to lower the speed of the combustion, but in reality, too much was probably getting through causing combustion too soon.

Some people Just love to waste their money...

What is octane?

Octane is a measure of a fuel's tendency to knock or ping when it is mixed with air and burned in the cylinder of an engine. This octane rating is not based on the amount of chemical octane in the gasoline. The rating is called octane because the gasoline's ability to prevent engine knock has been rated against the performance of pure hydrocarbon octane, which has a rating of

100. Gasoline, which is made from a blend of many other hydrocarbons, may have a higher or lower rating, depending on how its anti-knock performance compares to the performance of pure hydrocarbon octane.

Octane Facts

. Knock occurs when cylinder pressures are high. It is normal for an engine to ping a little at full throttle because cylinder pressures are very high at full throttle. Engine knock, however, should not be ignored since it can result in serious damage to the engine.

. High octane gasoline burns slower than low octane gasoline. The slow burn prevents engine knock when cylinder pressures are high.

. If your engine runs well and does not knock or ping on low octane gasoline, there is no advantage in switching to higher octane gasoline.

. If your engine knocks or pings, it does not necessarily mean something is wrong with the gasoline. It could be a problem with the engine's electronic control systems, ignition timing or exhaust gas recirculation. On a high mileage engine, a carbon build-up in the cylinders can increase cylinder pressures and cause knock.

. Almost all of today's new cars have fuel-injected engines that need to use gasoline with a detergent additive. They do not necessarily need high octane gasoline with a detergent additive. Generally, new automobiles need high octane gasoline only if the manufacturer recommends it.

. Always follow the auto manufacturer's octane recommendations in your owner's manual.

Octane Myths

. High octane gasoline improves mileage. In general, if your car is designed to run on 87 octane gasoline, high octane gasoline will not improve mileage. If switching to high octane gasoline does improve mileage, you might find that your engine, or its control systems, need repair.

. High octane gasoline gives quicker starting. No, it doesn't.

. High octane gasoline increases power. If your car is designed to run on 87 octane gasoline, you shouldn't notice any more power on high octane gasoline. Again, if it does make a noticeable difference, your engine, or the engine's electronic control systems, may need repair.

. High octane gasoline has been refined more - it is just a better product. Additional refining steps are used to increase the octane; however, these additional steps do not necessarily make the gasoline a "better" product for all engines. They just yield a different blend of hydrocarbons that burn more slowly. The additional steps also increase the price.

The Minnesota Department of Commerce, Weights and Measures Division; St. Paul, MN 55113-3800

Not really, with proper fuel it is not "normal" to knock at all.

Somewhat true, while it does burn a bit slower it also has a higher auto ingition temp too

Not true at all in a modern computer control engine with knock detection as it will quell knock by retarding spark before you hear it and make you falsely beleive that you are feeding it correctly while steal power effeciency and MPG. The ONLY reason there is a knock sensor is to limit consumer complaints on low octane fuel because many still beleive the 87 octane is the holy grail of fuels and the best to use.

Somewhat true but if you increase octane you will get rid of knock and if you change timing or other cotrol to reduce peak pressure and temp to quell knock you reduce overall efficency too.

This is wrong, they will all benifit from higher octane fuel, especailly in warmer weather or towing. The only reason that owner manual say 87 (and it does say minimum not the best possible) is because to state 89 or better would be a sales killer for those that are stuck on the holy grail of fuels hence the reason for the knock sensor.

Take some of them with a grain of salt because all EPA MPG tests are performed with 93 octane, not 87 but you will not find that in manual either.

Pure BS. Where do you get this crap? Every car I have bought in the last 15 year runs better and gets better MPG with 89 or better gas. I have a 89 suburb 4x4 that I bought new and it was a slug on a hot day with A/C and 87 octane when new and wanted to kncok some because not even knock control could control it completely. I have been running 93 in it for over 12 years now and it runs great!! Daughters Saturn is a slug on hot day with 87 octane but with 93 is is a different animal. The list goes on I do not use 87 octane in any of my cars but you can believe what you want too.

Sometimes it can if engine is hot and it is auto igniting and making cranking difficult

Again BS. Your modern engine is designed to tolerate it and nothing more because there will always be those that will use the cheapest gas they can find.

Not really true. Engine CR and load cycle and climate has a big input on octane requirements of fuel and you are suggestion that 100LL or

110 avgas is not good stuff. BTW most small A/C engine are low CR and they require 100LL because they know that you need good octane to get best possible power out of a engine because there is not room for knocking or pinging in flight nor for power loss from knock control.

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I used to run 89 in my cars because I DID get better mileage, and there seemed to be a noticeable difference in power. But when I tried that with my '02 Escape V6, I found that running a higher octane made no difference except in my wallet. I got 20-21MPG around town with both fuels, and 25-26 on the highway. I haven't tried 93 because I think it would be cost prohibitive, but if the prices keep dropping, I might. The only real difference I've noticed was the time I tried Enmark (10% ethanol). My mileage dropped by more than 15% around town, and there was a noticeable lack of power. I ran 3 tankfuls just to let the computer get used to it, but went right back to my old brand when there was no improvement.

SC Tom

It is not unusual for MPG to drop with E10 or E15 because of lower energy content. Also sometimes you have to force ECM's to work with better fuel by removing ECM fuse for about a minute and putting ECM back into learn mode

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I have tried that with the Escape when switching octanes, but it didn't have any different results. I'm not complaining, though- the vehicle gets reasonable mileage (to me), and has all the power I need.

SC Tom

My GM vehicle and a Jeep cherokee I have all do better power and MPG wise with better fuel. I never buy 87 for my vehciles no matter what the fuel cost is.

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