K24A3 & 310ccm cold engine jerks at low throttle

K-Series Programmable ECU Calibration updates / downloads
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sivo535
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K24A3 & 310ccm cold engine jerks at low throttle

Post by sivo535 »

Hello, have you met anyone with the fact that even in ekd the maps are relatively well tuned to +- 5% that a cold engine jerks at low throttle? It only happens until the engine reaches approx. 65-70°C. When the engine is warmed up, the engine no longer jerks, and the AFR also sits beautifully. The INOVATE LSU4.9 wide-spectrum lambda input to the ecu via the ELD pin is mounted. The closed loop is still ensured by the serial DENSO narrowband lambda probe. I don't know how to deal with it, I tried to add it to enriched when the engine was cold, but that didn't help either. When the temperature is low, the ECU drives the AFR CDM to 14.7:1 after a few seconds, which I think is bad, and I can't find how to set it so that the AFR adjusts it more slowly during engine warm-up.
I am attaching the LOG and the MAP in the log, notice the 36-41 seconds where tearing was recorded
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Spunkster
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Re: K24A3 & 310ccm cold engine jerks at low throttle

Post by Spunkster »

You need to have the secondary oxygen sensor enabled to run in closed loop.
sivo535
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Re: K24A3 & 310ccm cold engine jerks at low throttle

Post by sivo535 »

Why secondary O2?
For me, the system runs in a closed loop, I use primary O2 and so far everything has worked and is still working, the only problem is when the engine is cold.
Early on, the ECU instructs it to go to 14.7:1, even if it has a low temperature.

Explain to me why it is necessary to have a secondary o2? ECU is PRA with HONDATA V3
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Spunkster
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Re: K24A3 & 310ccm cold engine jerks at low throttle

Post by Spunkster »

This is how it was designed to work. As it says in the product info: https://www.hondata.com/products/kpro/kpro-s2000

see the notes
sivo535
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Re: K24A3 & 310ccm cold engine jerks at low throttle

Post by sivo535 »

But I don't have an S2000 or a PRB unit, I have a single PRA where both inputs are on O2 narrowband and I say that the closed loop is running and even the AFR that I monitor after warming up is fine, the only problem is when the engine is cold. When the engine warms up, it runs fine according to the O2 sensor. I also see a signal from the O2 sensor and it regulates the S.TRIM map. It responds to the primary lambda, so the closed loop is definitely running.

I didn't find anything in the description that would exclude the use of an O2 priar, and as I write, I don't have an S2000 or a PRB ECU.

Anything else that could be causing this jerking when the engine is cold?
PS: It is not a problem to repin the O2 sensor to the secondary one, but I don't see the point in that since oab are narrowband.
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Spunkster
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Re: K24A3 & 310ccm cold engine jerks at low throttle

Post by Spunkster »

Sorry I misunderstood, and thought you had a S2000.

I've not heard anyone else having an issue like this. What vehicle is this in?
sivo535
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Re: K24A3 & 310ccm cold engine jerks at low throttle

Post by sivo535 »

It is a SWAP K24A3 with a gearbox in a Z4 case, but the gears are from the original k24A3 6-speed manual, Injectors are 310ccm with K20A2. The exhaust pipes are still original, but the continuation is a custom-made stainless steel exhaust with an end muffler with an electronic valve that switches between the direct and damped tracts. There are two lambdas on the exhaust manifold, one with a Denso 4 cable and the other with a BOSH LSU4.9 controller from INOVATIVE. Its output is connected to the ELD pin and also to the on-board computer where I can see the current values. It's all installed in a 2000 Civic EK3.

I noticed in the logs that it happens immediately and the narrow-band lambda heats up to operating temperature and the system switches to close loop. I don't understand why he tries to achieve afr 14.7:1 in the 39 seconds after the start, when the engine is still only 25°C. This is a bad enrichment and AFR can be seen in the maps he attached. See Image.
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Spunkster
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Re: K24A3 & 310ccm cold engine jerks at low throttle

Post by Spunkster »

PRA ECU's really should only be used in an actual EP3 Type R Civic and should not be used for engine swaps. This is why we do not even socket or use these ECU's for US markets as we know it may cause some undesired effects when not used in an EP3.
sivo535
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Re: K24A3 & 310ccm cold engine jerks at low throttle

Post by sivo535 »

That's not an explanation. Since HONDATA supports ecu with PRA code, it must have treated behavior.
I would like someone from vivo to explain to me why AFRCDM tells edu to set the ratio to 14.7:1 as soon as it goes into closed loop already at a temperature of 25°C. If anyone knows where this course can be set or what is wrongly set in my calibration, I will be grateful.
sivo535
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Re: K24A3 & 310ccm cold engine jerks at low throttle

Post by sivo535 »

So problem solved. The problem was in the wrong setting of the corrections and the fuel pressure regulator after disconnecting the negative pressure gave a higher pressure than it was originally set, therefore the map was 10% out of the optimal ratio and since the engine is in open loop mode when the lambda is cold, when it warms up he tried to correct it immediately and took fuel, which caused the hesitation, so the map is fine-tuned, the delay cut is turned off, and wow, it sounds great both in the cold and in the heat
EbayJesus
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Re: K24A3 & 310ccm cold engine jerks at low throttle

Post by EbayJesus »

Hey sivo535, i'm also using a pra ecu with k24a3, what calibration did you use it to start with? thanks a lot
sivo535
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Re: K24A3 & 310ccm cold engine jerks at low throttle

Post by sivo535 »

At the beginning, I tried the original, which Hondata's offer for the K24A3 engine is included in Others, but I didn't really like it when I found out that the VTEC turns on this map already at 1800 rpm. so I looked at the map with the TSX and that was a better basis, so I tried the map with the TSX, it suited me better, also because I use a 310cc injector that had the original TSX to split from the k24A3, which has 270cc. The rest is already in the debugging of the maps
EbayJesus
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Re: K24A3 & 310ccm cold engine jerks at low throttle

Post by EbayJesus »

did you manage to turn on the car with the tsx base map? Did you get any errors in kpro?
sivo535
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Re: K24A3 & 310ccm cold engine jerks at low throttle

Post by sivo535 »

Yes, I managed to run the map with TSX on the PRA controller with euro civic type r. It is already reasonably tuned, only the fully open throttle is fine-tuned when there is no time to run to the dyno. The engine has already driven 30,000 km, after 4 oil changes and a check of the throttle body and clutch mechanism, everything is still in order. The mixture constantly follows INNOVATE WIDEBAND and I watch the recordings when my afr moves outside the allowed hysteresis. For now, I want to be satisfied, but I want to upgrade the Honda to the V4 version, I currently drive the V3
EbayJesus
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Re: K24A3 & 310ccm cold engine jerks at low throttle

Post by EbayJesus »

Thank you very much, I'll try with that.
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