Knock / Ignition adaptations

[S54B32]

Interested as well to know what normal ranges are considered to be, the lower the better I get that, just wonder what most healthy engines are showing in this regard.
I'm glad my "spread" is fairly even across all cylinders for what it's worth.

In my opinion that’s not looking very good, if your tune is based on CSL PD31. If I remember correct, the max knock adaption is limited there to 2.00°cr. So it can‘t go any higher than 2.00°. So if all knock adaptions are maxed out to max, you have to much ignition advance in your tune for you engine or wrong fuel.

I got similar results with wrong fuel in tank, I mapped my CSL based tune to 102 octan (German premium fuel) and when I put 98 in my tank I also have 2.00° across all cylinders.

[sapote]

the CPS sensors are probably ready to be changed as I'm around 70k.

I would leave the old but perfectly working sensor alone. NASA would love to use the parts that had survived the tough screening tests. NASA don't use the brand new parts just out of the oven, but subjecting them in a series of stress tests before approving the parts.

[Cubieman]

These are my "normal" numbers. It does run slightly rich as you can see by slightly low LTFTs (normally about 0.92-0.93 on both banks)

Seem a bit closer to zero than some here, assuming zero is perfect?

I had similar numbers before I modded out the car, once the Karb intake went on and it was tuned etc.

Not sure what to do about it if anything, the CPS sensors are probably ready to be changed as I'm around 70k. But something tells me it's just how my car runs now with a different intake, no MAF, and different exhaust.

[Shonky]

These are my "normal" numbers. It does run slightly rich as you can see by slightly low LTFTs (normally about 0.92-0.93 on both banks)

Seem a bit closer to zero than some here, assuming zero is perfect?

[sapote]

I replaced both CPS and the vanos adaptations got cut down in half (-2/-4 to -1/-2) which was nice..

Sorry to pop the bubble but replacing CPS's is like using a different yardstick to measure Usain Bolt's speed -- longer stick says he ran 8 yd/sec and shorter stick measured 10 yd/sec. As the vanos timing wasn't adjusted then nothing really changed.

As about ignition adaption, I wonder these values were for certain rpm, as ignition timing varies according to rpm: less advance at low rpm and more advance at higher rpm.
The value is heavily depending on the condition of the combustion chamber; more carbon built up or hot temperature could lead to detonation and so more negative adaptation. Higher compression tend to have more negative adaptation.

[Tbonem3]

Anyone have anything else to contribute?

I've been doing a lot of maintenance on my new S54, but it's still around -4 across all 6 cyl. I replaced both CPS and the vanos adaptations got cut down in half (-2/-4 to -1/-2) which was nice. But ignition stayed at about -4 across all 6 cyl.

So the car is sensing too much fuel, not enough air, and is pulling back? But the air filter and MAF are new and the intake tract is clean/smooth, airbox is clean inside. Every sensor and filter has been replaced except for crank and knocks. Vanos solenoid from besian, but that could still be an issue maybe.

Checked for vacuum leaks, though vacuum issues would cause lean condition I think. Ignition is pulled across all 6 cyl so not a bad plug, coil or injector. No issues with fueling as far as start up/idle. Idle is rock steady.

Very confusing. Car runs strong, no codes, but I want perfect.

I do have catless headers (cats now in sect 1), but I'm not sure how relocating cats would cause changes to AFR. I didn't think you *needed* a tune after fitting catless headers (though it is recommended ofc)

I'm thinking I need to do a vanos test.

[Tbonem3]

Ya I wonder too. I, too, have even #s.

My silvergrey car has really low #s for vanos and ignition, and that car runs like a top, so I think we are being hindered. I've done a fair amount of work lately, but not driven the car much, so I think I need to drive it hard for a while and see if there's improvement while we wit for more info.

[Cubieman]

Interested as well to know what normal ranges are considered to be, the lower the better I get that, just wonder what most healthy engines are showing in this regard.
I'm glad my "spread" is fairly even across all cylinders for what it's worth.

[Tbonem3]

Any updates?

I'm getting around -3 to -4 on all cylinders. Car feels strong, but it does seem to be holding back and a little "surgey" No codes, so I'm not sure if I should just replace knock sensors, crankshaft position sensor, etc.. Already did coils, plugs, air filter, fuel filter, valve adjust, vanos solenoid/seals.

[Neil I]

Knock adaptations are a good thing, as the DME is retarding the ignition timing to prevent possible engine damage caused by pre-ignition or detonation. Unfortunately reducing ignition advance is generally bad for power, so I guess one other question is how often does the DME refresh these knock adaptations? If it's a frequent thing then what we are seeing could just be a 'snapsho't which could be due to a tank of bad gas/fuel of applying too much engine load at low rpm, causing knock etc.

[ATB88]

Yeah to be clear I'm not saying that my knock adaptations are an issue but providing them as an example. I'm more trying to get an idea of what "good" and "bad" knock adaptations are (or if trying to classify them in that way is even sensible), and for example, if there's even a sense in which comparing yours to mine is a sensible thing to do, and if we can say that yours are worse. Also what kinds of problems we can learn about with these values if we are experiencing problems with how our cars are running.

[Neil I]

Thanks for posting these questions, I have a similar issue and was going to do the same. My ignition adaptations are slightly worse than yours, but the car seems to run perfectly with no error codes.



I checked a few things on the weekend, just so that I could eliminate these as possible causes of knock. These were - valve clearances - all within spec and the majority at the smaller end of the clearance range, spark plug gaps - all correct, and compression test - max deviation across all cylinders was 4psi. Engine is on 57k miles so I'm assuming the injectors are still in good condition. The coil packs were replaced last year, so are practically new.

Hopefully someone will be able to answer your questions and explain more about these values

[ATB88]

My intent with this thread isn't to try and diagnose a particular problem that I'm having, but to learn more about what these values are, what they tell you, and when/how it would make sense to use them as a diagnostic tool. I'm a curious and I'm just trying to learn and understand as much as I can about how our DME runs things. But if my car's particular values below do point to a problem, then all the more interesting. Sorry if the below points to me not really knowing what I'm talking about -- I don't and that's kind of the point, I'd like to change that

Knock Adaptations:

My understand of knock adaptations: these numbers tell you the number of crankshaft degrees that spark/ignition timing on any particular cylinder is being advanced/retarded in order to optimize combustion and have the engine run smoothly (minimize knock). The DME builds these based on data collected over time from the knock sensors, I presume? I'm also guessing that the point of the DME doing this is so that it can still run well when you have a bad coil, plug, injector etc that isn't behaving quite as the engine expects, is

I just read mine with my Schwaben tool and they read:

Cyl 1: -4.41 deg
Cyl 2: -2.81 deg
Cyl 3: -2.81 deg
Cyl 4: -0.81 deg
Cyl 5: -2.41 deg
Cyl 6: -3.21 deg

So, it looks like ignition timing is being pulled to varying degrees across all cylinders. Car is running stock tune, 93.x octane (I fill with a mixture of 100 octane and 91).

Question 1: I'm also guessing that the point of the DME having this capability is so that it can still run well when you have a bad coil, plug, injector etc that isn't behaving quite as the engine expects, is this right? Is there a sense in which knock adaptations are also important to account for natural manufacturing variability between different cars or different cylinders/valves on the same car? Does it make sense to compare knock adaptations from one car to another, and is there an objective standard of where you should want them to be (say, close to 0), or is it just as-is information that has more to do with quirks of your particular engine vs. how well it's objectively running?

Question 2: Cyls 2,3,5 are all pretty close to each other, with Cyls 1, 4, 6 looking like possible outliers. Does it matter if these numbers are uniform or could non-uniformity point at potential problems?

Question 3: Do any of these numbers being high (say, like cyl 1 in my case) indicate a potential for loss in performance? I've read people say things like "my DME's pulling timing" as a negative. Is that in reference to these numbers or would that refer to something else?

Idle Synchronisation Adaptations:

I haven't really ever seen/heard these values discussed before. Is it because they're not very informative/meaningful? Would be interesting to know what they mean.

My Schwaben tool gives values in microseconds (uS) for each cylinder. For example, mine look like

Cyl 1: +100
Cyl 2: -77
Cyl 3: -23
Cyl 4: -64
Cyl 5: -34
Cyl 6: +98

Interestingly the cylinders with the highest deviations (1 and 6) in these adaptations are also those with the highest timing retardation in the Knock adaptation. Any relationship between the two?

Thanks for any information any of the more knowledgeable people are able to give me about this, I'd really like to learn more!