Anger
Senior Member
- First Name
- Nick
- Joined
- Sep 24, 2018
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- 4
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- 380
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- 227
- Location
- Greece
- Vehicle(s)
- FK7,RW2,RD1,RD5,RE5,RU1,FK1,FN2,EP3
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- #16
Mini update on my fuel trims.
Despite having the stock intake installed, fuel trims remain negative. After googling, came across this paragraph:
" Excessive crankcase vapors or a flooded EVAP canister can also mimic excess fuel, especially at idle. If the oil hasn’t been changed in a long time, especially in an older engine with a bit of blow-by, fuel in the oil can drive total fuel trim negative. Often simply changing the oil will demonstrate this condition by returning the fuel trim numbers to normal."
This makes me think about the oil dilution issue. This is only the second winter I have the car but the first tuned and most importantly, the first when I monitor the engine. I had checked the oil levels two to three weeks ago and it was slightly overfilled but not concerning. At the time however, ambient temps were normal to high. I do a daily commute of 20 minutes/ 22 km and the car is warmed up properly only when I get to work and actually have to switch it off. The proper way of understanding if the engine is heated up is the oil temp, not the water temp. Since we cannot monitor oil temps, what I do is turn the heater on and see if the water temp drops. If it does, my guess is that the engine is not warm enough. I start driving after 1 minute when I do a cold start, drive very conservatively for 10-12 minutes and then drive slightly faster or a gear down for another 10 minutes when the weather is cold.
I have arranged for a full service next week (I do oil change at 5000-6000km max, now I have 30000km and will also do MTF, rear diff and spark plugs) but I will return the car to stock tomorrow and do the oil/oil filter change as soon as possible and see how things go. I will not unlock Ktuner from the car so I can monitor the engine on the factory maps.
UPDATE: Today I changed oil and oil filter. In theory, oil change filter included is 3.5 liters. We did 3.3, started the car for the filter to fill up and re checked. The dipstick showed it was missing 500ml which stroke as weird. Added another 200, still showed that it needed another 250ml. I did not add them. Stopped at 3.5 as the manual states.
I drove for only 3km back to work. The trims are already looking better. I will check for another 2 days and see how the trims go. First impression is that the fuel trims issue was caused by oil dilution.
UPDATE 2: Fuel trims with the stock airbox went back to normal. Only slightly negative. Reinstalled the PRL SRI and trims are also back to normal, dead 0 on highway with steady throttle and slightly negative in traffic. All I do now is let the car idle for 3 minutes instead of 1 after a cold start.
It seems that the issue was oil dilution. Tbh the ambient temps dropped back to 32-37F while my testing after the oil change it was about 45-50. Will keep monitoring.
Despite having the stock intake installed, fuel trims remain negative. After googling, came across this paragraph:
" Excessive crankcase vapors or a flooded EVAP canister can also mimic excess fuel, especially at idle. If the oil hasn’t been changed in a long time, especially in an older engine with a bit of blow-by, fuel in the oil can drive total fuel trim negative. Often simply changing the oil will demonstrate this condition by returning the fuel trim numbers to normal."
This makes me think about the oil dilution issue. This is only the second winter I have the car but the first tuned and most importantly, the first when I monitor the engine. I had checked the oil levels two to three weeks ago and it was slightly overfilled but not concerning. At the time however, ambient temps were normal to high. I do a daily commute of 20 minutes/ 22 km and the car is warmed up properly only when I get to work and actually have to switch it off. The proper way of understanding if the engine is heated up is the oil temp, not the water temp. Since we cannot monitor oil temps, what I do is turn the heater on and see if the water temp drops. If it does, my guess is that the engine is not warm enough. I start driving after 1 minute when I do a cold start, drive very conservatively for 10-12 minutes and then drive slightly faster or a gear down for another 10 minutes when the weather is cold.
I have arranged for a full service next week (I do oil change at 5000-6000km max, now I have 30000km and will also do MTF, rear diff and spark plugs) but I will return the car to stock tomorrow and do the oil/oil filter change as soon as possible and see how things go. I will not unlock Ktuner from the car so I can monitor the engine on the factory maps.
UPDATE: Today I changed oil and oil filter. In theory, oil change filter included is 3.5 liters. We did 3.3, started the car for the filter to fill up and re checked. The dipstick showed it was missing 500ml which stroke as weird. Added another 200, still showed that it needed another 250ml. I did not add them. Stopped at 3.5 as the manual states.
I drove for only 3km back to work. The trims are already looking better. I will check for another 2 days and see how the trims go. First impression is that the fuel trims issue was caused by oil dilution.
UPDATE 2: Fuel trims with the stock airbox went back to normal. Only slightly negative. Reinstalled the PRL SRI and trims are also back to normal, dead 0 on highway with steady throttle and slightly negative in traffic. All I do now is let the car idle for 3 minutes instead of 1 after a cold start.
It seems that the issue was oil dilution. Tbh the ambient temps dropped back to 32-37F while my testing after the oil change it was about 45-50. Will keep monitoring.
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