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Discussion Starter #1
Alright, I have started quite a few threads lately, but I have just found out how knowledgeable everyone on here is and I am full of issues/questions!

So throughout last summer I was having an issue where my logs would show as high as +7 knock but only when lightly accelerating (light or no boost at all). Also when cruising at a consistent speed anywhere for 60-80mph it would occur as well. It would never happen at WOT or even 3/4 throttle. It also does not happen every single time either so it seems quite inconsistent as well.

I have been through all of the threads on here back to 2013/14 or so and lots of other guys have had this issue, however not one thread posts any kind of resolution to the issue? Lots of suggestions are to just ignore it unless its happening at WOT. However! the big problem with this is, the positive knock reading absolutely kills my OAR - so when I do decide to floor it, the truck makes no power with OAR number usually sitting at Positive 0.80 or higher.

I have tried different gas over 6 months of driving and it occurred the exact same regardless of fuel grade or quality. Stock tune, Unleashed tune, Gearhead tune they all do it. The only slight bandaid fix was Torrie turned down the knock sensor sensitivity until I was only ever seeing +3 at most which helped the OAR a lot. Matt did not want to even begin tuning for the methanol until this was sorted which I can understand. The frustrating part is I have no idea how to sort it out!

My only guess as to what it could be would be the exhaust? somehow vibrating enough to trigger knock sensors - I have checked heat shields are solid and it is not contacting anything but the exhaust hangers. If it is the exhaust I am not sure how to go about correcting this then either!

Hopefully in the last 7+ years someone has found the resolution to this!!
 

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There should be no knock at cruise on flat ground because there is no load and you're in vacuum.

At partial throttle, not a concern, although it shouldnt be really high.

OAR does not chnage by throttle, it is the gas. Postive OAR means your gas is ****. I have -.99 on 93 in the summer, which is as good as it gets. Right now on winter 87 I see -.03 when i last checked. The scale is -1 to +1
 

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Common problem, especially with Canadian Gas. Happens in all gears (but more so with lower gears), at low rpm (below 2000) and with boost levels between 0 and 5 psi. And only when you are over 7.5psi will you start to see -KR.

The only solution is the spark tables need to be adjusted, especially for Canadian Gas.

And, if you were to find a tuner who would 're-work' the spark/rpm/load tables, you may spend a lot of money with minimal results as often lowering the spark advance in the tables doesn't entirely eliminate the problem.

I have driven countless miles on the highway with LOTS of -KR. The OAR barely moves. But when I pull into city traffic, whatever minor negative OAR I may have got on the highway is elimiated and the KR and OAR goes POSITIVE.

That is why I locked out the OAR years ago. I drove on the highway with the Stock Tune forcing the OAR to -.96 (lowest it would go), then I load an special tune I had made by Torrie to lock the OAR. When I load that tune, the OAR becomes permanently locked at -.96.

Yes, I will see +KR still at the low rpm/load (locking the OAR does not disable the knock sensor) except for Low rpm/load in low gears, my KR is either 0 or slightly negative.

BUT.... the truck performs MORE CONSISTENTLY!. With the OAR unlocked, my truck's performance is no where near as consistent with the OAR Locked. IT seems to have "good days" and "bad days". I now realize it has to do with the OAR and the type of driving I was doing. Lots of highway, next day truck runs good. Done a lot of city traffic, truck runs like crap. Locking the OAR eliminated this.

PS: Most tuners will NOT lock your OAR unless they are comfortable they you know the potential danger and know what to watch for. You MUST constantly monitor your spark advance and KR. If you notice ANY weird behavior (like +KR all over in all rpms/load ... possibly due to bad gas or poor octane gas), immediately remove the locked OAR tune and install the "unlocked" OAR tune ... or even the stock tune.
 

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Didn't Madmax overcome this issue finally?

I think so if I remember correctly.
And it was tuner expertise that helped him.

Although he is a 2.7, same issue.

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PPS: As Wooboost said, for the trucks engine perspective, at low rpm/load the risk is minimal. The mixture is not a volatile, and cylinder pressures are not as high as in wide-open throttle. As well, locking the OAR does not lock the KR (which is dangerous and done by a particular tuner to get the highest performance for his tunes ... often with disastrous results.

Just make sure you do lots of wide-open datalogs so the tuner can see the effect, and get the tune right for WOT (when things are more critical).


PPPS: I am doing experiments with Canadian Gas and adding Methanol. Even with M25, I still see some +KR at low rpm/load ... just showing the stock spark advance tables are too aggressive in the at range. Everywhere else, I have -KR. And that is with the OAR locked at -.96 and adding an extra 4* spark advance in WOT. And in WOT I show 11-12* total Spark Advance and the PCM has -2 to -4 KR. Truck runs like a scalded ape, and it looks like it can handle more spark advance in WOT.

Once I am finished, I will be making a post for those Canadians suffering from crumby gas, and how to add methanol to create an M25 mixture. I am also looking for a place that will sell me methanol in 55 gallon drums to lower cost. I found one wholesaler, but he said the smallest bulk they sell is a RailCar. Tempting.
 

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LSPI. I dealt with it on my old 2013 as well. As mentioned there’s not a whole lot you can do for it but make sure you run good oil, change it fairly often and run good quality fuel.

I never did figure it out with my 2013 and my 2017 2.7 did not have the issue neither does my 2019 3.5


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I've had a few instances where I also got some crazy part throttle KR on my 2011 and 2018. I don't however get it when running my 5* tunes. Maybe they addressed it, maybe not. But as Ike said. Good quality oil changed often, plus good quality fuel will help.
 

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Didn't Madmax overcome this issue finally?

I think so if I remember correctly.
And it was tuner expertise that helped him.

Although he is a 2.7, same issue.

Sent from my SM-N950U using Tapatalk
Not really. I just quit worrying about it. My tunes from Boostking are better than anything else I've run, except one tuner who desensitized my knock sensors in the areas where I have the knock. That took care of it too lol.

In my case, lowering the timing in the areas of the tune where I was getting the drastic spikes made it WORSE. Way worse. Oddly enough.

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Not really. I just quit worrying about it. My tunes from Boostking are better than anything else I've run, except one tuner who desensitized my knock sensors in the areas where I have the knock. That took care of it too lol.

In my case, lowering the timing in the areas of the tune where I was getting the drastic spikes made it WORSE. Way worse. Oddly enough.

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Well as usual, my senior recall was corrupt.

But at least your post is additional data for the other fellas.

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Even on e30 and e50 it was occurring. Mixed e85 and top tier 93. It did not seem to have anything to do with octane or actual fuel quality for me.

With other tunes the OAR will swing all the way down and back again within the same tank of fuel. Multiple times in a single trip even.

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Sounds like it could be something else other than actual knock. as stated, maybe the sensors are picking up some weird vibration. Maybe a funky turbo bearing or frozen blinker fluid or who knows what.
 

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It is all signs that the OEM Spark Tables need to be recalibrated, especially for lower rpms/load.

I fought something similar on another vehicle I was DIY tuning. Lowering the OEM spark advance in certain tables based on load/rpm fixed the problem.

Most tuners DO NOT tweak/tune the Spark Tables for normal part-throttle tuning. They don't charge enough to do this. And it can take a long time to get all the proper rpm/load values corrected. They rely on the OEM Spark Adavance tables especially for part-throttle, and those tables are wrong at low rpm/load.

What tuners typically only work on the TOP END performance that only that come into play in WOT. Many don't even tweak the OEM tables, but will go to some special table that deals with WOT. In the GM world, they call it "Power Enrichment". Not sure what the Ford engineers call their WOT/Power Enrichment tables.

PS: Just for a laugh, I put Race Gas additive to force my octane over 100. Top end was ALWAYS -KR. But still had a little +KR in the low rpm/load range. For ALL the vehicles with this same problem, it tells me Ford put a little too much Spark Advance at low rpm/load range knowing that it really isn't danger due to weak cylinder pressures, and you still have the KR.

What it does screw up is the OAR. The OAR gets skewed by the +KR in low part-throttle like city driving and almost ignores the high -KR I get on the highway or under load. It's like the OEM tables needs to have spark removed at the bottom part and added in the top part.
 

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In my case, lowering the timing in the areas of the tune where I was getting the drastic spikes made it WORSE. Way worse. Oddly enough.
Actually, that can happen. Or ... you lower it, and the +KR only goes down a little bit.

When I was in the GM world tuning, we concluded that the OEM tables (especially low rpm/load) were purposely given extra spark advance to help with throttle response. The more spark you add to the OEM tables (for part-throttle) will increase your throttle response. Removing timing from the Spark Tables (for part-throttle) will reduce your throttle response and even make it feel "spongy".

Luckily, those particular PCMs didn't have an OAR. Just a good old Knock Sensor. Which is basically, what I am doing now with the OAR disabled, and relying solely on the KR to add/remove spark advance. But with the OAR locked, my truck is faster and runs very consistent. No good days/bad days like I use to get with the OAR functioning.

As I said, Torrie and I are going to play with this a bit and see if we can correct it (and I can start using the OAR). But for the meantime, I locked my OAR at -.96.
 

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I'm not sure if @trev is still kicking around, but he was fighting this too. Not sure if he figured out the root cause.
That was when I got into this whole BS, and found my OAR was at +.99. All because I drove "in the city" from Abbotsford to Surrey.

The OAR is the culprit (and at this point, the OAR is undesirable IMO). The problem is the OEM Spark Tables at low rpm/low load. And lowering the spark advance may not even work.

If I had an "Adaptive Tune", my truck would run like crap.
 

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When I was testing with Mike at MPT we mailed down specific areas of the tune and conditions where the KR would occur, and I mean maxed out as many degrees as he had set in the tune.

Always the same thing, moderate load moderate throttle. It would hold until I let off the pedal. I could feel the truck fall flat on its face and if I were to try pressing on into the go pedal I wouldn't get much out of it until I released and tried again.

Anyway after nailing down where it was occurring, he removed a lot of timing just in those areas. I believe he said to less than stock values. This is with 93 in the tank mind you. Oddly enough, it made the situation way, WAY worse. I could hardly drive the truck. KR city no matter what I did. I could barely get to 55 mph a single time without KR just being flat pegged constantly and OAR going straight to a +.96 in a matter of minutes.

I got my log, pulled over, loaded an earlier revision that wasn't part of the experiment, and things were pretty normal after that with only the occasional part throttle issues. By the end of the next drive settled back to -.96.

I don't wholly know what to make of that experiment, but it was interesting. Mike said it was evidence to him that we were surely dealing with false knock.

The cause? That remains to be seen.

At 83,000 miles I'm over it. I can kind of hear when the engine is where it may be happening. I can tell by low rpms and a sort of whooooooosh sound of air moving. My guess is maybe the wastegates letting off boost. Or perhaps just the sound of boost in the engine when the rpms are low ish.

I manage it with a flick of the go pedal or a manual bump on the "-" button if I have to.

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@mwemaxxowner

Heh, heh. I remember when you first brought this up, and I even phoned you to "don't worry about the part-throttle KR ... it's normal". I still am of that view. In reality, low rpm/low load +KR generally will not cause any problems. High rpm, very different story.

FYI, I am going to work with Torrie and experiment with removing some spark advance at low rpm/low load. I have 3.5 so my engine might be a little different, but I expect to find the same thing as you (because I had this happen on previous vehicle that I was DIY tuning).

Also, with the OAR activated, have you ever monitored your KR? I found that if the PCM updated the OAR in a "negative direction" (i.e. a lower positive or higher negative), then the KR in areas where I was getting large negative values is now lower (as the OAR does affect the amount of total spark advance). And areas where the KR was slightly negative are now positive KR. Ditto on the reverse, if the OAR goes positive, I start to see more -KR all over.

Problem is, I can drive hundreds of miles on the highway all with -KR and get the OAR to a high negative value. BUT, the moment I pull into the city (and ours city has LOTS of hills), the KR immediately goes positive and causes the OAR to suddenly go from a nice negative to a dreaded positive value. ... in fact the city I live is an Indian Word, and I swear it means "Lots of F'ing Hills".

I have come to regard the OAR like "Communism". It sounds great in theory, but in practice it doesn't really work.

My happiest day with my truck was the day I locked the OAR (and got the PCM to ignore it).

PS: I can think the dealership for causing me to get back into this. I will explain in the future, when I have done more testing with Torrie. Hard right now, as the many of the roads are icy. AND, if dry, cold pavement doesn't grip well.

As well, I would prefer to do these tests when the ambient air temperature is closer to the temp of my past tests...for consistency.
 

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When this is going on, and the OAR gets worse (goes more positive) my KR still acts the same as it ever does. Adds here, pulls there, pulls a lot at medium loads (and maxed out even) and the truck falls on its face.

As mentioned, I don't really let it happen like that any more. Usually a bump down a gear and a bit of throttle and I avoid it. I also avoid certain tunes. All 5* performance tunes are out for me and all adaptive tunes for everybody are out.

I will also gear down as needed ahead of time if I see a challenging hill coming, especially if I'm towing. Avoid a problem altogether.

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I'm over figuring it out. Lol

I slapped a big ol band aid on it that works well enough and only then was I able to really enjoy my truck again.

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Discussion Starter #20
There should be no knock at cruise on flat ground because there is no load and you're in vacuum.

At partial throttle, not a concern, although it shouldnt be really high.

OAR does not chnage by throttle, it is the gas. Postive OAR means your gas is ****. I have -.99 on 93 in the summer, which is as good as it gets. Right now on winter 87 I see -.03 when i last checked. The scale is -1 to +1
Well no it doesnt change by throttle, however OAR is directly effected by Knock, more knock drives the number more negative which then also pulls timing back. On one single tank of 94 I can see -0.96 all the way to + 0.96 based on what the knock is doing.

Common problem, especially with Canadian Gas. Happens in all gears (but more so with lower gears), at low rpm (below 2000) and with boost levels between 0 and 5 psi. And only when you are over 7.5psi will you start to see -KR.

The only solution is the spark tables need to be adjusted, especially for Canadian Gas.

And, if you were to find a tuner who would 're-work' the spark/rpm/load tables, you may spend a lot of money with minimal results as often lowering the spark advance in the tables doesn't entirely eliminate the problem.

I have driven countless miles on the highway with LOTS of -KR. The OAR barely moves. But when I pull into city traffic, whatever minor negative OAR I may have got on the highway is elimiated and the KR and OAR goes POSITIVE.

That is why I locked out the OAR years ago. I drove on the highway with the Stock Tune forcing the OAR to -.96 (lowest it would go), then I load an special tune I had made by Torrie to lock the OAR. When I load that tune, the OAR becomes permanently locked at -.96.

Yes, I will see +KR still at the low rpm/load (locking the OAR does not disable the knock sensor) except for Low rpm/load in low gears, my KR is either 0 or slightly negative.

BUT.... the truck performs MORE CONSISTENTLY!. With the OAR unlocked, my truck's performance is no where near as consistent with the OAR Locked. IT seems to have "good days" and "bad days". I now realize it has to do with the OAR and the type of driving I was doing. Lots of highway, next day truck runs good. Done a lot of city traffic, truck runs like crap. Locking the OAR eliminated this.

PS: Most tuners will NOT lock your OAR unless they are comfortable they you know the potential danger and know what to watch for. You MUST constantly monitor your spark advance and KR. If you notice ANY weird behavior (like +KR all over in all rpms/load ... possibly due to bad gas or poor octane gas), immediately remove the locked OAR tune and install the "unlocked" OAR tune ... or even the stock tune.
See I guess what doesnt make sense to me about that is if it truly is canadian fuel as the problem, then why the problem does not vary regardless what octane rating or station I get the fuel from, also this seems to be an issue that occurs in the exact same way for owners around the US as well! I guess torrie did something similar with my OAR, he didnt lock it in but he did turn down sensitivity in the knock sensors which in turn resulted in the OAR always staying very negative!

Unfortunately it sounds like even those who have had the spark table adjusted to be a little more tame did not solve the problem either so that is kind of concerning!


LSPI. I dealt with it on my old 2013 as well. As mentioned there’s not a whole lot you can do for it but make sure you run good oil, change it fairly often and run good quality fuel.

I never did figure it out with my 2013 and my 2017 2.7 did not have the issue neither does my 2019 3.5


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from my understanding LSPI usually occurs in scenarios of higher boost, low engine speed, and high engine low. this occurs sometimes with little to no boost or engine load and does not seem to react any different other times when there is engine load or boost. Oil is always fresh and running 94 has not helped either!

Even on e30 and e50 it was occurring. Mixed e85 and top tier 93. It did not seem to have anything to do with octane or actual fuel quality for me.

With other tunes the OAR will swing all the way down and back again within the same tank of fuel. Multiple times in a single trip even.

Sent from my Moto Z3 Play using Tapatalk

Yes exactly what you are talking about sounds like my issue on a single tank my OAR will be from minimum to maximum multiple times within one drive to the store even. I have tried adding Octane boost (the stuff that actually works) to get my octane to the 97 or so rating and saw no difference. I have turned my meth controller to start spraying at 2 psi and still saw no change in knock - and we all know meth should nearly almost always prevent knock.

It just doesnt add up, are the factory settings on the sensors just too sensitive? does everyone have this issue also have an aftermarket exhaust which could be triggering it? the inconsistency of it also makes it challenging to understand what could be causing it that only happens every 2nd or 3rd time..
 
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