How to fix weird Knock Retard

[ShoBoat]

Sunoco is not a Top Tier gasoline, but I assume your regular station was a high-volume one at least?  I know a couple of people who had KR with Sunoco gas resolve it by moving on to Exxon or Shell etc.

Agreed, I have personally noticed when filling up at a really busy station vs a dead one. KR was noticeably more with the dead one. Corn is always best when fresh


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[14 TUX BL]

Sunoco is not a Top Tier gasoline, but I assume your regular station was a high-volume one at least?  I know a couple of people who had KR with Sunoco gas resolve it by moving on to Exxon or Shell etc.

Agreed, I have personally noticed when filling up at a really busy station vs a dead one. KR was noticeably more with the dead one. Corn is always best when fresh

The Sunoco station is indeed a high volume station, one that I've been going to for a long time (it's close too). I read where Mobil was Top Tier gas and Sunoco was not, but for some reason we have very few Mobil stations where I live. But I think it is definitely a better choice and will be using it just to see if the problem returns.

Quick aside:
A couple of years ago I had a new Coyote Stang that intermittently lost power. I thought maybe it could be the gas so I went elsewhere for fuel, but the problem continued and it eventually threw a code. Turned out it was a loose OHC sensor plug.

 

[ZSHO]

I tend to stay away from gas stations that have a 5-10 cents off a gallon especially that particular day. Z

 

[ZSHO]

If your issues continue personaly would pay a visit to your local dealer and possibly a re-flash is in order. Z

 

[wasinger3000]

So what's the consensus on knock in relation to fuel economy. Is it more economical to run a higher octane to prevent knock which will reduce the amount of fuel sprayed in compensation of the knock. Or is it not worth the price increase over 87? I'm taking the f150 on a trip over 4k miles and it's not tuned so no need for 91.

 

[ShoBoat]

So what's the consensus on knock in relation to fuel economy. Is it more economical to run a higher octane to prevent knock which will reduce the amount of fuel sprayed in compensation of the knock. Or is it not worth the price increase over 87? I'm taking the f150 on a trip over 4k miles and it's not tuned so no need for 91.

We run 91 in our 11 Explorer Limited. I noticed a jump in economy since the change from 87. From 17L/100km down to 14.5 ish. (Sorry about the metric) Mixed driving. It's also better for the car/truck. Keep in mind that around these parts 91 has no corn so that might also be a factor.


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[ShoBoat]

Forgot to mention that ours has the factory tune.


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[SHOnUup]

So what's the consensus on knock in relation to fuel economy. Is it more economical to run a higher octane to prevent knock which will reduce the amount of fuel sprayed in compensation of the knock. Or is it not worth the price increase over 87? I'm taking the f150 on a trip over 4k miles and it's not tuned so no need for 91.

I've read that using 93 gets better mileage and ends up being same money spent as using 87...but your vehicle would appreciate the higher octane, and is better for it.

Rich

 

[wasinger3000]

So what's the consensus on knock in relation to fuel economy. Is it more economical to run a higher octane to prevent knock which will reduce the amount of fuel sprayed in compensation of the knock. Or is it not worth the price increase over 87? I'm taking the f150 on a trip over 4k miles and it's not tuned so no need for 91.

I've read that using 93 gets better mileage and ends up being same money spent as using 87...but your vehicle would appreciate the higher octane, and is better for it.

Rich

Yeah I don't really ever want to use 87 just not sure if it is worth using in a truck that gets terrible milage as it is. I'll be using archoil in the fuel so I'm not worried about deposits.

 

[14 TUX BL]

Yeah, if the issue presents itself again I'll take a trip to the dealer.

Went for a ride tonight, and in the hot/humid air it performed really well. Will keep an eye on it ... 

 

[ajpturbo]

So what's the consensus on knock in relation to fuel economy. Is it more economical to run a higher octane to prevent knock which will reduce the amount of fuel sprayed in compensation of the knock. Or is it not worth the price increase over 87? I'm taking the f150 on a trip over 4k miles and it's not tuned so no need for 91.

I've read that using 93 gets better mileage and ends up being same money spent as using 87...but your vehicle would appreciate the higher octane, and is better for it.

Rich

Then u read a bad article...a fuels octane rating is its ability to resist preignition..common myth that higher octane yields better mpg and burns hotter....running higher octane fuel than what the vehicle was tuned for will only increase operating cost...the car doesn't appreciate anything....commanded lambda will remain the same no matter the fuel being used...

 

[ajpturbo]

I wish some of u guys that had tunes would ask your tuner how much more spark advance of they run...not that u would get a straight answer anyway....but...I know that some are advancing the spark and relying on the knock sensor to ride the edge of knock for the purpose of running the most amount of spark the given fuel will handle..

I can set the tune in a manor that I run 87 octane And not only will u see 0 knock retard but the ecu will add more timing...it's all on how the base tables are set.

Adding 2-3 degrees is a quick way to get 20hp then u just let the knock sensor pull timing if it hears some knock....I think some of u guys are way to sensitive to a little knock retard now and again.

Not only are there tables in the tune to limit how much timing is added or pulled based on the knock sensor but also tables that control how quickly or slowly spark is added or pulled

Learned knock tables should be treated like stft...I'd like mine to hover around 0...if it's always on one side or the other then your tables need work...surprising the stock timing tables work amazingly well...looking at the tables ford spent a lot of time dialing in about the max amount of spark that can be tolerated at each load and rpm cell in the tune

 

[14 TUX BL]

The performance of our SHO benefits from Premium Fuel:

(below taken from 2014 Sales Brochure and Owner's Manual)

 

[ajpturbo]

Correct...our particular cars do benefit due to the tuning....some cars are only tuned for 1 fuel...our cars can make the best use of multi fuels....not all cars have learned knock logic built into the tunes but a lot of new cars do

 

[SHOdded]

AJ is correct.  Stock, my Edge only runs on 87 fuel.  I'd have to load a separate tune for 91 and a separate tune for 93 just to account for the octane difference!  The 2011+ Edge benefited from tuning for fuel octane adaptability, however.  Using higher octane fuel to make the engine "run better" when it is not tuned for it is primarily done to a) take advantage of the deposit-removing additives generally found in premium fuel, and/or b) cover up combustion issues that cause ping/knock.

 

[14 TUX BL]

Right aj, bone stock SHO's develop more hp when using Prem fuel:
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
EDMUNDS
http://www.edmunds.com/ford/taurus/2010/road-test-4/
"The result is 365 hp ... on 93 octane ... those of us in deprived 91-octane states should hit this number. The EcoBoost mill will run on 87 octane regular ... but the output will fall off a bit."
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Bottom line, we will lose some hp on a bone stock engine if we use Reg.

 

[SHOnUup]

So what's the consensus on knock in relation to fuel economy. Is it more economical to run a higher octane to prevent knock which will reduce the amount of fuel sprayed in compensation of the knock. Or is it not worth the price increase over 87? I'm taking the f150 on a trip over 4k miles and it's not tuned so no need for 91.

I've read that using 93 gets better mileage and ends up being same money spent as using 87...but your vehicle would appreciate the higher octane, and is better for it.

Rich

Then u read a bad article...a fuels octane rating is its ability to resist preignition..common myth that higher octane yields better mpg and burns hotter....running higher octane fuel than what the vehicle was tuned for will only increase operating cost...the car doesn't appreciate anything....commanded lambda will remain the same no matter the fuel being used...

I've only watched about a 100 guys report on better mileage in their F150 ecoboost by moving up to premium...they all must be lying?

Rich

 

[FoMoCoSHO]

So what's the consensus on knock in relation to fuel economy. Is it more economical to run a higher octane to prevent knock which will reduce the amount of fuel sprayed in compensation of the knock. Or is it not worth the price increase over 87? I'm taking the f150 on a trip over 4k miles and it's not tuned so no need for 91.

I've read that using 93 gets better mileage and ends up being same money spent as using 87...but your vehicle would appreciate the higher octane, and is better for it.

Rich

Then u read a bad article...a fuels octane rating is its ability to resist preignition..common myth that higher octane yields better mpg and burns hotter....running higher octane fuel than what the vehicle was tuned for will only increase operating cost...the car doesn't appreciate anything....commanded lambda will remain the same no matter the fuel being used...

I've only watched about a 100 guys report on better mileage in their F150 ecoboost by moving up to premium...they all must be lying?

Rich

Well, what are their testing methods? Just like the track, there are too many variables to know.

If there was any advantage to MPG with premium, you can bet Ford would lock it down to premium to get those extra CAFE points.....manufacturers are seriously under the gun with future fuel economy requirements....

 

[SHOnUup]

So what's the consensus on knock in relation to fuel economy. Is it more economical to run a higher octane to prevent knock which will reduce the amount of fuel sprayed in compensation of the knock. Or is it not worth the price increase over 87? I'm taking the f150 on a trip over 4k miles and it's not tuned so no need for 91.

I've read that using 93 gets better mileage and ends up being same money spent as using 87...but your vehicle would appreciate the higher octane, and is better for it.

Rich

Then u read a bad article...a fuels octane rating is its ability to resist preignition..common myth that higher octane yields better mpg and burns hotter....running higher octane fuel than what the vehicle was tuned for will only increase operating cost...the car doesn't appreciate anything....commanded lambda will remain the same no matter the fuel being used...

I've only watched about a 100 guys report on better mileage in their F150 ecoboost by moving up to premium...they all must be lying?

Rich

Well, what are their testing methods? Just like the track, there are too many variables to know.

If there was any advantage to MPG with premium, you can bet Ford would lock it down to premium to get those extra CAFE points.....manufacturers are seriously under the gun with future fuel economy requirements....

From a TON of guys on ecoboosted page...doubt it was very scientific. But many mentioned the change in mileage on the same daily commute they always take. Could be them easing off the throttle a bit to reinforce the idea, but if was a wave of guys.

Rich

 

[wasinger3000]

So what's the consensus on knock in relation to fuel economy. Is it more economical to run a higher octane to prevent knock which will reduce the amount of fuel sprayed in compensation of the knock. Or is it not worth the price increase over 87? I'm taking the f150 on a trip over 4k miles and it's not tuned so no need for 91.

I've read that using 93 gets better mileage and ends up being same money spent as using 87...but your vehicle would appreciate the higher octane, and is better for it.

Rich

Then u read a bad article...a fuels octane rating is its ability to resist preignition..common myth that higher octane yields better mpg and burns hotter....running higher octane fuel than what the vehicle was tuned for will only increase operating cost...the car doesn't appreciate anything....commanded lambda will remain the same no matter the fuel being used...

I've only watched about a 100 guys report on better mileage in their F150 ecoboost by moving up to premium...they all must be lying?

Rich

Well, what are their testing methods? Just like the track, there are too many variables to know.

If there was any advantage to MPG with premium, you can bet Ford would lock it down to premium to get those extra CAFE points.....manufacturers are seriously under the gun with future fuel economy requirements....

From a TON of guys on ecoboosted page...doubt it was very scientific. But many mentioned the change in mileage on the same daily commute they always take. Could be them easing off the throttle a bit to reinforce the idea, but if was a wave of guys.

Rich

I'll try 500 miles of 91 then 87 and see where it stands.