knock question

[GrabberBargeCaptain]

I can feel the car pull timing hard sometimes on 91 octane on 105+ degree days. I can't imagine using 87 octane on a hot summer day. That's for granny going back and forth to church with an egg under the gas pedal.

No one is saying it isnt knock… you said you need to run 91 … clearly you don’t read the manual as that isn’t true. Of course 99% of people run 91-93.i was stating that the manual says and some
People do run 87 and are fine… which points to either bad gas or another problem with this guys car.

The manual literally says dont be worried if you hear knock at times , but if it happens at the RECOMMENDED octane rating (91+) then you should be concerned.

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[RNM]

No one is saying it isnt knock… you said you need to run 91 … clearly you don’t read the manual as that isn’t true. Of course 99% of people run 91-93.i was stating that the manual says and some
People do run 87 and are fine… which points to either bad gas or another problem with this guys car.

Guy runs 89 octane in Los Angeles where I am sure it is hot and says he hears a metallic noise when going 50-100 throttle.

The noise goes away on 91.

You know what? Op should just run 87 octane and see if that hopefully solves the issue.

 

[GR1MxREAPER]

OP the moral of the story and what most of us are saying is yes you can run 87 octane but be prepared to maybe have a little knock and You really should run 91/93 as this is a very high compression engine and it likes good gas. If you try 93 octane or octanium/boostane and it still Does it then maybe it’s something rubbing or vibrating or something more severe wrong with your engine, bring it to a dealer or a trusted shop.

 

[robvas]

The guy above literally just did bro . And you
Showed a picture with 91 gas highlighted . You can’t make this up.

Again, nobody said it can't run on 87.

 

[K4fxd]

If I were in Ca I'd want to run 87 or 89 too, but and this is a big but, I would never hit more than 25% throttle, especially on hot days or going up hill.

These engines are strong but any engine that is knocking audibly is destroying itself. This is true despite what Ford puts in the owners manual. What they call light knock is light enough that anyone hearing it might think they are hearing things. The computer is designed to pull enough spark and in a way that if it does knock it will appear to be intermittent to the driver.

It will sense a knock event then pull spark, knock goes away. Then due to the design it will advance timing till it hits another knock event. You as driver might hear these or might not. It should not be audible to a normal person.

If your car is knocking continuously or loudly you need better gas. If it is knocking loudly on 91/93 you need to see a dealer.

 

[ice445]

If you do have knock from carbon fouled pistons there's pretty much nothing you can do about it. Main reason I sold my car. On the stock tune with 91 it was usually fine, hearing knock was rare outside of climbing hills at slow speed. 87 was useless except maybe in winter. And trying to use a tune was a hilarious exercise in frustration. Nearly constant audible knock with logged values over 6-8 degrees of timing retard.

When I initially scoped my cylinders I didnt think anything was amiss. But after seeing other peoples pistons on here I can see why i was having problems. My pistons were 100% coated black. Couldn't even see the valve reliefs. Only clean spot was where the direct injector sprays. I assume its from oil getting past the rings which only a short block replacement would fix.

I get what everyone is saying, 91+ is ideal for these engines. But it should run on 87 without much noticeable pinging even in hot weather. Should being the key word. Warranty wont touch this, they'll just tell you to run 91 and plug your ears until it blows up at 90k miles or whenever it gets tired of the abuse, lol.

 

[Garfy]

The noise definitely fades away with 91. But that's my issue... whether I fill up with 87 or 89, it shouldn't be doing this in the first place especially given that Ford says 87 is OK.

Frankly, I've run my car on 87 when I first bought it during break-in and I never had any issues with detonation; only obvious thing was a very noticeable difference in power. That being said, IF you're actually experiencing detonation (spark knock, ping, etc.) then you have a problem with your engine control system. I'm assuming your car has the same 4 knock sensors that mine does, and if the system is functioning correctly, the PCM should retard ignition timing when it detects detonation, and it can detect it long before we can even begin to hear it. If you're truly experiencing these symptoms, I doubt the scanner will show it is detecting knock, for if it shows it, then there's something wrong with the PCM if it's not retarding ignition timing to prevent it.

 

[robvas]

I was amazed how much knock showed and timing was pulled tuning 87 on a GM 6.2 truck. But people drive them like that for years.

If you do have knock from carbon fouled pistons there's pretty much nothing you can do about it. Main reason I sold my car. On the stock tune with 91 it was usually fine, hearing knock was rare outside of climbing hills at slow speed. 87 was useless except maybe in winter. And trying to use a tune was a hilarious exercise in frustration. Nearly constant audible knock with logged values over 6-8 degrees of timing retard.

When I initially scoped my cylinders I didnt think anything was amiss. But after seeing other peoples pistons on here I can see why i was having problems. My pistons were 100% coated black. Couldn't even see the valve reliefs. Only clean spot was where the direct injector sprays. I assume its from oil getting past the rings which only a short block replacement would fix.

Nothing Seafoam or water injection can't fix

 

[Pistol_91]

You can run 87 all day long in all weather scenarios. I just would not go WOT. I mean really what's the point of trying to go fast when you have go slow fuel in. I get it if you're just driving to work and back but if you're trying to go fast, atleast put 91/93 in it.

87 in my f150 eco pulls a shit ton of timing if I log and do a WOT pull. Couldn't imagine the high compression coyote motor.

 

[K4fxd]

Like I told the dumbass I built a race engine for. Race gas is cheaper than another engine. He said race gas is too expensive and 93 is fine. He is needing a new engine after 5 races.

Ford designed these engines around 91 and made software to run 87. Actually they made software to run 91. I would run 100 if I could get it at the pump. 12 to 1 needs good gas.

 

[ice445]

I was amazed how much knock showed and timing was pulled tuning 87 on a GM 6.2 truck. But people drive them like that for years.


Nothing Seafoam or water injection can't fix

Just a temporary fix, it should never have gotten like that in the first place, especially by 20,000 miles lol

 

[RNM]

The noise definitely fades away with 91. But that's my issue... whether I fill up with 87 or 89, it shouldn't be doing this in the first place especially given that Ford says 87 is OK.

You caused your own engine damage.

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