Cheekano
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« on: March 31, 2022, 02:30:23 AM »
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Good Day,
I have installed an RS4 MAF on my Focus ST 2.5 and currently dialing it down.
I have scaled the MSHFMU based on the numbers posted on here and currently have set both FKKVS and KFKHFM to 1.
I am currently logging both STFT and LTFT.
My question is, if there are discrepancies on the STFT, how do I know which map to tweak?
Thanks in advance
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prj
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« Reply #1 on: March 31, 2022, 08:46:44 AM »
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If your injectors are stock and the factory did a half decent job then you should not set FKKVS to 1... keep it stock.
And then you know what map you have to edit.
Of course it's Ford so...
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Cheekano
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« Reply #2 on: March 31, 2022, 09:48:27 PM »
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Thanks. Yes, I'm still on stock injectors.
And yes, I agree that Ford isn't really the most consistent. It's weird because on the Focus RS bin file, the FKKVS are all set to 1...but on the RS500 bin file, it has changes (not all 1s).
Both of them have changes on the KFKHFM but is the same values for both.
Is it suitable to just change the FKKVS to 1 and tweak the KFKHFM to suit the new MAF?
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IamwhoIam
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« Reply #3 on: April 01, 2022, 02:32:29 AM »
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What kind of RS4 MAF have you installed and what kind of bonnet mods have you done in order to install what I think you've installed in your Focus RS?
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I have no logs because I have a boost gauge (makes things easier)
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prj
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« Reply #4 on: April 01, 2022, 05:12:14 AM »
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Thanks. Yes, I'm still on stock injectors.
And yes, I agree that Ford isn't really the most consistent. It's weird because on the Focus RS bin file, the FKKVS are all set to 1...but on the RS500 bin file, it has changes (not all 1s).
Both of them have changes on the KFKHFM but is the same values for both.
Is it suitable to just change the FKKVS to 1 and tweak the KFKHFM to suit the new MAF? If you have stock injectors then use whatever FKKVS came with the car. FKKVS is to adjust injectors and fueling system. KFKHFM is to adjust MAF. To be more exact FKKVS affects only injection time KFKHFM affects the load calculations. If your fuel trims were fine on whatever FKKVS there was before, and now you changed only MAF, then you should not touch FKKVS at all. Modify KFKHFM so that it works like before. After that once you change injectors start adjusting FKKVS. |
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Cheekano
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« Reply #5 on: April 01, 2022, 04:20:16 PM »
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What kind of RS4 MAF have you installed and what kind of bonnet mods have you done in order to install what I think you've installed in your Focus RS?
I don't have an RS. I have a ST but fitting in the K16 on it from the RS. All my intake from the airbox to the lower manifold is not stock anymore. |
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nyet
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« Reply #6 on: April 01, 2022, 04:26:24 PM »
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FKKVS is to adjust injectors and fueling system
Question: is FKKVS more relevant for injector specific non-linearities or fuel pressure/pump/rail/return (if none) variance? Or a combination of both, all at once... that is to say, if you change injector but nothing else, would there be more changes than changing fuel system but nothing else, or ... can't say, it depends on the interaction between both? |
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ME7.1 tuning guideECUx PlotME7Sum checksumTrim heatmap toolPlease do not ask me for tunes. I'm here to help people make their own. Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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Cheekano
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« Reply #7 on: April 01, 2022, 04:29:24 PM »
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If you have stock injectors then use whatever FKKVS came with the car.
FKKVS is to adjust injectors and fueling system. KFKHFM is to adjust MAF.
To be more exact FKKVS affects only injection time KFKHFM affects the load calculations.
If your fuel trims were fine on whatever FKKVS there was before, and now you changed only MAF, then you should not touch FKKVS at all. Modify KFKHFM so that it works like before.
After that once you change injectors start adjusting FKKVS.
Ah I see. Thank you for the explanation, it makes much more sense now. It also explains why the RS500 have different values on the FKKVS as it's technically have more boost and advance timing on some areas so it richens the afr more through FKKVS. |
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prj
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« Reply #8 on: April 01, 2022, 04:35:05 PM »
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Question: is FKKVS more relevant for injector specific non-linearities or fuel pressure/pump/rail/return (if none) variance?
Or a combination of both, all at once... that is to say, if you change injector but nothing else, would there be more changes than changing fuel system but nothing else, or ... can't say, it depends on the interaction between both?
Both. Injectors are not 100% linear. EV14 are very good of course. But both. Ah I see. Thank you for the explanation, it makes much more sense now. It also explains why the RS500 have different values on the FKKVS as it's technically have more boost and advance timing on some areas so it richens the afr more through FKKVS.
The last statement is completely wrong. FKKVS is not a fuel map. It is there to correct for non-linearity of the fueling system. You really need to get the basics right. It's not a shitty oldschool ECU with a single map. It KNOWS what "afr" (lambda) it is requesting. It also knows what the actual is from a wideband sensor and it runs closed loop. FKKVS has exactly 0 effect on request. The reason it is different is most likely because the fuel system is different - I don't know anything about Ford variants. If you were to just increase values in FKKVS you would NOT get more fuel because it would pull exactly the same amount back through WBO2 (on narrowband you would, but beside the point). The reason it exists is because the fueling system is not linear and it is there to correct the output of the calculation so that actual lambda matches request. Same as KFKHFM is there to correct the MAF value so that load (and calculated ps_w) matches reality. None of these maps are used for mixture control. For mixture control (setpoint) on ME7 only LAMBTS, LAMFA and ATR are used when not in start mode. |
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« Last Edit: April 01, 2022, 04:40:16 PM by prj »
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Cheekano
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« Reply #9 on: April 02, 2022, 08:39:46 AM »
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Both. Injectors are not 100% linear. EV14 are very good of course. But both.
The last statement is completely wrong. FKKVS is not a fuel map. It is there to correct for non-linearity of the fueling system.
You really need to get the basics right. It's not a shitty oldschool ECU with a single map. It KNOWS what "afr" (lambda) it is requesting. It also knows what the actual is from a wideband sensor and it runs closed loop.
FKKVS has exactly 0 effect on request. The reason it is different is most likely because the fuel system is different - I don't know anything about Ford variants.
If you were to just increase values in FKKVS you would NOT get more fuel because it would pull exactly the same amount back through WBO2 (on narrowband you would, but beside the point).
The reason it exists is because the fueling system is not linear and it is there to correct the output of the calculation so that actual lambda matches request. Same as KFKHFM is there to correct the MAF value so that load (and calculated ps_w) matches reality.
None of these maps are used for mixture control. For mixture control (setpoint) on ME7 only LAMBTS, LAMFA and ATR are used when not in start mode.
Okay, thanks. AFAIK, hardware-wise, they are identical. I'll do some more digging especially on the fueling side to see why the discrepancy. |
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Cheekano
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« Reply #10 on: April 02, 2022, 11:50:08 PM »
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UPDATE:
So I compared both bin files in detail and it seems another map difference is the KPNDSOL - Low pressure set point values (manifold injection). There's zero results on google about it but looking at the information, it seems to be the minimum fuel rail pressure (returnless system). Hope someone can confirm?
The one on the RS500 has different values, which could be the reason why the FKKVS is different on that one.
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curamrdan
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« Reply #11 on: April 03, 2022, 02:56:05 AM »
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Its quite some time i touched ford, but one important difference. Facelift vehicles have returnless fuel system with mechanical regulator inside fuel tank and its NOT pressure referenced, so KPNDSOL is doing nothing there and you run out of injector pretty quickly. RS500 is a facelift.
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prj
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« Reply #12 on: April 05, 2022, 08:11:53 AM »
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If you only changed the MAF, simply leave everything alone, change the main curve, and then change KFKHFM if it's off anywhere, and job done.
If you change the injectors, change KRKTE, and then change FKKVS.
You don't really need to set everything to all 1, but you need to learn how to plot corrective matrix graphs from fuel trim and overlay them to get new values...
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Cheekano
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« Reply #13 on: April 07, 2022, 03:33:28 AM »
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Its quite some time i touched ford, but one important difference. Facelift vehicles have returnless fuel system with mechanical regulator inside fuel tank and its NOT pressure referenced, so KPNDSOL is doing nothing there and you run out of injector pretty quickly. RS500 is a facelift.
Yes, the one I have is a returnless system. If you only changed the MAF, simply leave everything alone, change the main curve, and then change KFKHFM if it's off anywhere, and job done.
If you change the injectors, change KRKTE, and then change FKKVS.
You don't really need to set everything to all 1, but you need to learn how to plot corrective matrix graphs from fuel trim and overlay them to get new values...
Thank you for the replies, I appreciate it. I think I have got the concept of it now. The RS4 MAF is now installed and somewhat running okay. I used the RS4 MLHFM definitions and transpose the values over. Intervention was kicking in at first. Tried adjusting it based on STFT but was not working too well for me as the values don't quite line up - so I remembered what you mentioned and I tweaked the KFKHFM based on rl_w and rlsol_w difference - and it worked a lot better though some places I'm still seeing a dip/increase. I initially was set on keeping the MLHFM values the same for the RS4 as I'm feeling a bit sacrilegious editing it but I saw a few posts that it's actually easier to edit MLHFM and leave KFKHFM and FKKVS alone as there is less editing involved so I might try it that way as well. |
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prj
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« Reply #14 on: April 07, 2022, 05:08:37 AM »
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MLHFM should not be modified.
KFKHFM is the one you need to modify. And it should be modified based on fuel trim.
Log load, rpm, fuel trim.
Plot it as a matrix graph.
Create a correction overlay, correct it.
Also, not a single log was posted in this thread. Better start doing that.
You like to assume a fuck ton. Most likely you have not had any "intervention" either, more like overboost and throttle shut or something else.
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