Manes Posted March 31, 2023 Report Share Posted March 31, 2023 Hi, I installed NGK U5014 coils on a B18C4 turbo respecting the wiring (independent test ok) The vehicle starts but I have continuous misfires. I can't understand where it comes from knowing that the engine was running correctly with a Honda S300 beforehand. The mechanical cause therefore seems to be ruled out! In addition I have 2 new COP sets and changing them does not change anything. It's a G4X HC92. I put you a quick test drive log and the base map (nothing is adjusted for the moment I'm just trying to fix the problems) https://we.tl/t-QlCd4gMSXf (the log) Thx for your help map not tuned.pclx Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 1, 2023 Report Share Posted April 1, 2023 Under what conditions does it misfire? Are you sure it is not knocking its brains out? Your ignition table has 34deg advance at 150kpa and 38deg advance at 200Kpa, I cant imagine a honda on pump gas will like that much. The only other observation is in the early part of the log you have overrun fuel cut kicking in a lot and probably too much dwell for the VAG coils, but it looks different in the later part of the log and the map is different again, so I assume you have changed many settings since the log was done? Quote Link to comment Share on other sites More sharing options...
Manes Posted April 2, 2023 Author Report Share Posted April 2, 2023 the engine runs on ethanol and I agree the advance are extremely important but that's what gave the best results on the dyno. With less the egt flies away . The knock sensor was seeing less and less noise with the addition of advance on top of that ! In short, the engine needs all of this! It puts out 400 engine hp with a g25-550 at just over 1 bar. I actually changed a lot of things on the map but it seems that the problem is ultimately mechanical. the problem persists with the S300, the compression is good the ignition is present an injector problem seems likely... Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 2, 2023 Report Share Posted April 2, 2023 11 hours ago, Manes said: the engine runs on ethanol So did you attach the wrong map? The map you attached is only set up for pump gas, the stoich ratio and density etc are all petrol values, even crank enrichment etc is like 1/5 of what would typically be needed to get an ethanol engine to fire. Something is very wrong if it needs that much advance, like the cam timing is out or possibly base timing isn't set correctly or trigger sensor polarity is incorrect etc. B18's typically reach MBT about 26deg if the fuel can support it. You only ever see 34-38deg at full boost either with exotic slow-burning fuels or in very old school engines with hemi or bathtub chambers. Quote Link to comment Share on other sites More sharing options...
Manes Posted April 3, 2023 Author Report Share Posted April 3, 2023 The stoichiometric ratio only varies the display off I like working with gasoline afrs. As we know the afr being only the coefficient of the said fuel by the lambda it does not change anything. For the effective density I did not change it. We are currently in E60 and the oilman gives a density very close to gasoline. For the cranking enrichment on my first tries, I had actually upgraded everything for the cranking but didn't take the time to do it on the map I joined you. However, the vehicle starts very well. I agree with you, those are the results I usually get. This engine is forged and has a compression ratio of 9 instead of the more than 10 of origin. the advance are surely due to that i think. the camshafts have an adjustment close to the origin (increased crossing for more sweeping) and the beam is original so it would be surprising if there was a polarity problem The engine has a cnc worked cylinder head, 9 compression ratio, custom stainless steel exhaust manifold, 3 inch line, skunk 2 pro intake manifold Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 3, 2023 Report Share Posted April 3, 2023 11 minutes ago, Manes said: The stoichiometric ratio only varies the display off I like working with gasoline afrs. As we know the afr being only the coefficient of the said fuel by the lambda it does not change anything. For the effective density I did not change it. We are currently in E60 and the oilman gives a density very close to gasoline. That assumption is incorrect since you are using Modeled fuel equation. When using modelled fuel equation your "fuel table" is actually a VE table, from that and the calculated air density the ecu can calculate the mass of air that will be ingested into the cylinder. To then calculate the mass of fuel that is required to achieve your desired AFR it needs to know the correct stoichiometric ratio of that specific fuel. Since the injector flow rate is specified in volume per unit time, the ecu also needs to know the correct density for the specific fuel to calculate how much injection time is required to inject the correct mass of fuel. If you dont have the correct fuel, engine and injector properties when using modelled fuel equation you can end up with some of the compensations exaggerated and working against you. AFR will drift off target as boost or temperature changes etc. Quote Link to comment Share on other sites More sharing options...
koracing Posted April 3, 2023 Report Share Posted April 3, 2023 If you want to view Lambda in gasoline AFR you can use a math channel - but for the fuel model, the values do need to be entered correctly. Quote Link to comment Share on other sites More sharing options...
Manes Posted April 6, 2023 Author Report Share Posted April 6, 2023 I did not think about that ! Thank you for the information I will correct and make me a small math function to see the afr sp98 Quote Link to comment Share on other sites More sharing options...
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