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Title: Missfire in cylinder-4 with adaptation of lambda heater not passed. MED 9.1 Post by: Albertoak on March 25, 2020, 08:10:33 AM Hey guys !!
Well, what the title says ... I would like to know if anyone has had the same thing in Med 9.1 I explain the situation ... Cold car, lambda heater adaptation and lambda, reset. I start the car and go for a ride. Back, adaptation of past lambda heater (I understand that it only does it from cold starts). I stand still with the engine started in idle. ALL missfire counters on all cylinders to 0. All ok. Following the above without moving. Reset adaptation of lambda and lambda heater. I stay still with the engine in idle and before long (I don't remember if 30sg, 1 minute ...) the missfire counter of cylinder 4 starts to count missfire until it reaches 29 in less than 2 minutes I think .... and come back again. Aim in general. that the car running and wot, there are no missfires, after rescaling maf almost does not delay ignition in wot (-1.5-2 degrees, above nothing), perfect lambdas at 0.82 and runs like a missile. change spark plugs and cylinder coils and it plays the same ... it's weird. I would like to understand why that happens .... because the engine is perfect. if anyone has a little idea. Good to Know. thanks!! Title: Re: Missfire in cylinder-4 with adaptation of lambda heater not passed. MED 9.1 Post by: bamofo on March 25, 2020, 08:40:54 AM Hey guys !! Well, what the title says ... I would like to know if anyone has had the same thing in Med 9.1 I explain the situation ... Cold car, lambda heater adaptation and lambda, reset. I start the car and go for a ride. Back, adaptation of past lambda heater (I understand that it only does it from cold starts). I stand still with the engine started in idle. ALL missfire counters on all cylinders to 0. All ok. Following the above without moving. Reset adaptation of lambda and lambda heater. I stay still with the engine in idle and before long (I don't remember if 30sg, 1 minute ...) the missfire counter of cylinder 4 starts to count missfire until it reaches 29 in less than 2 minutes I think .... and come back again. Aim in general. that the car running and wot, there are no missfires, after rescaling maf almost does not delay ignition in wot (-1.5-2 degrees, above nothing), perfect lambdas at 0.82 and runs like a missile. change spark plugs and cylinder coils and it plays the same ... it's weird. I would like to understand why that happens .... because the engine is perfect. if anyone has a little idea. Good to Know. thanks!! What are your fuel trims before you reset everything with your cable? ST and LT fuel trims before and after might point to why your seeing a random misfire. Title: Re: Missfire in cylinder-4 with adaptation of lambda heater not passed. MED 9.1 Post by: Albertoak on March 25, 2020, 08:44:58 AM What are your fuel trims before you reset everything with your cable? ST and LT fuel trims before and after might point to why your seeing a random misfire. they are normal values. sf at 0.2-0.3 and lf over 3. I still need to finish adjusting the rescaling of the intake yet .... But I do not understand the action of the ecu .... if the heater check is not passed lambda, is when it throws the missfires in cylinder 4 ... as soon as that check passes, everything is ok. Title: Re: Missfire in cylinder-4 with adaptation of lambda heater not passed. MED 9.1 Post by: bamofo on March 25, 2020, 08:47:07 AM they are normal values. sf at 0.2-0.3 and lf over 3. I still need to finish adjusting the rescaling of the intake yet .... But I do not understand the action of the ecu .... if the heater check is not passed lambda, is when it throws the missfires in cylinder 4 ... as soon as that check passes, everything is ok. So shut the car off, reset it, keyoff keyon, then repeat. my Q7 flashes almost every light on the dash if i try to do that while its running. Title: Re: Missfire in cylinder-4 with adaptation of lambda heater not passed. MED 9.1 Post by: Albertoak on March 25, 2020, 08:57:36 AM So shut the car off, reset it, keyoff keyon, then repeat. my Q7 flashes almost every light on the dash if i try to do that while its running. mmm you gave me an idea .... to reset without starting the car. only active contact .... but I'm still looking for an explanation to that ... Title: Re: Missfire in cylinder-4 with adaptation of lambda heater not passed. MED 9.1 Post by: bamofo on March 25, 2020, 09:52:53 AM mmm you gave me an idea .... to reset without starting the car. only active contact .... but I'm still looking for an explanation to that ... You just reset all the controls for the Lambda Sensors. Including Heating. Log what the O2 sensor is doing while you do that if your interested in it. Someone else will have to help you from here.. i just wouldnt reset it while its running.. If your arm hurts when you hit it but its fine all the rest of the time... then just dont hit it.. Title: Re: Missfire in cylinder-4 with adaptation of lambda heater not passed. MED 9.1 Post by: Albertoak on March 25, 2020, 10:37:23 AM You just reset all the controls for the Lambda Sensors. Including Heating. Log what the O2 sensor is doing while you do that if your interested in it. Someone else will have to help you from here.. i just wouldnt reset it while its running.. If your arm hurts when you hit it but its fine all the rest of the time... then just dont hit it.. a quick solution would be to deactivate the lambda heater diagnosis and that's it ... but I think it is a slop. if the lambda heater breaks, you don't know ... I'm going to try logging in when it happens. Title: Re: Missfire in cylinder-4 with adaptation of lambda heater not passed. MED 9.1 Post by: Albertoak on March 26, 2020, 11:28:29 AM This is for everyone who reads, says nothing or wants to solve it hahahaha. I like to contribute to this forum.
In the end it was a problem of MAF rescaling. Rescale the maf correctly and 0 missfires. Perfect adaptation values and 0 delays. |