I'm no expert, so please take my response with caution, and I'm currently googling etc.
But as I understand it, disconnecting the lambda should force the car into its closed loop state. If so, and if the lambda is at fault then the car should improve its idle etc. If it doesn't then it might point to an issue elsewhere such as the TPS etc, suggesting the lambda is fine.
The other option is to buy the MBE cable and watch the value in Easymap which I believe should oscillate between two values, sorry can't remember what. From my research I believe the ECU has to keep changing the mixture slightly to permit the O2 to determine the difference between ambient and that in the exhaust. Well that's my understanding. If the value is static or way out then it would indicate the O2 at fault.
May be someone with more knowledge can add some more here?
I am no expert either but I think that if the lambda is faulty the ECU would detect that and go to open loop anyway. So disconnecting the lambda might make no difference for some or all of the time.
Personally, I would want to get to the bottom of the problem rather than just accept it. It’s a modern engine which should run smoothly, particularly if it did before. If it doesn’t idle properly then it probably doesn’t run properly when driving and the engine is on-load - it’s just far less noticeable.
Changing the lambda sensor is a bit of a shot in the dark but as it gets very hot is maybe more likely to fail, maybe. There are other sensors too such as ambient temp, engine temp, barometric pressure etc. which could be the cause.
Mine has its original sensor from 2015, I had the uneven idle etc until changing to RBTBs in 2016. After the RBTBs were fitted the popping and banging increased of course.
More recently I’ve fitted a decat pipe. Still the same lambda sensor.
Without using Easimap to see what's truly going on, debugging a problem like this is, I'm afraid, going to be a somewhat hit-or-miss affair. For example, it could be due to a faulty lambda sensor, poor earthing, or a poor lambda connection. But it could also be due to a TPS problem such that the idle position is not being translated into the correct mapping site -- without seeing what Easimap has to say, you won't be able to tell. The irony is that cash spent on unnecessary replacements adds up to the point where you're well on the way to affording a diagnostic cable!
I understand your reluctance to shell out on an MBE cable (yes, they are crazy expensive, but at least the software is free!), but I feel that's really the only viable DIY solution given your remote IoM location.
If it's any help, I have an MBE cable which I'll happily lend you, provided you're willing to pay two-way postage and insurance. If you're interested, just PM me your postal address plus a contact email address too. But I won't be able to send it off until the end of next week as I'm abroad at the moment.
Yes, mine has a Lambda. Does anyone know what they're from?
If it's the same as my Duratec 420, shipped last year then its a MG Rover MHK10006, with a description of Lambda Oxygen Sensor - CSR.
Rimmerbros seem to have them in for about 50quid.
Cheers for that Minty. How do we test if it's the lambda?
I'm no expert, so please take my response with caution, and I'm currently googling etc.
But as I understand it, disconnecting the lambda should force the car into its closed loop state. If so, and if the lambda is at fault then the car should improve its idle etc. If it doesn't then it might point to an issue elsewhere such as the TPS etc, suggesting the lambda is fine.
The other option is to buy the MBE cable and watch the value in Easymap which I believe should oscillate between two values, sorry can't remember what. From my research I believe the ECU has to keep changing the mixture slightly to permit the O2 to determine the difference between ambient and that in the exhaust. Well that's my understanding. If the value is static or way out then it would indicate the O2 at fault.
May be someone with more knowledge can add some more here?
+ Swapping in a good one and looking for changes. But that won't catch some bad connections. And it does need to be a good one.
Jonathan
Thanks and agreed Jonathan, although it would be handy to diagnose before purchasing.
I'm only aware of the main loom connection for the O2, and of course the main ECU harness plug. Anywhere else of concern connectivity wise?
I am no expert either but I think that if the lambda is faulty the ECU would detect that and go to open loop anyway. So disconnecting the lambda might make no difference for some or all of the time.
Personally, I would want to get to the bottom of the problem rather than just accept it. It’s a modern engine which should run smoothly, particularly if it did before. If it doesn’t idle properly then it probably doesn’t run properly when driving and the engine is on-load - it’s just far less noticeable.
Changing the lambda sensor is a bit of a shot in the dark but as it gets very hot is maybe more likely to fail, maybe. There are other sensors too such as ambient temp, engine temp, barometric pressure etc. which could be the cause.
Mine has its original sensor from 2015, I had the uneven idle etc until changing to RBTBs in 2016. After the RBTBs were fitted the popping and banging increased of course.
More recently I’ve fitted a decat pipe. Still the same lambda sensor.
Still idles pretty much perfectly.
Re #25:
Without using Easimap to see what's truly going on, debugging a problem like this is, I'm afraid, going to be a somewhat hit-or-miss affair. For example, it could be due to a faulty lambda sensor, poor earthing, or a poor lambda connection. But it could also be due to a TPS problem such that the idle position is not being translated into the correct mapping site -- without seeing what Easimap has to say, you won't be able to tell. The irony is that cash spent on unnecessary replacements adds up to the point where you're well on the way to affording a diagnostic cable!
I understand your reluctance to shell out on an MBE cable (yes, they are crazy expensive, but at least the software is free!), but I feel that's really the only viable DIY solution given your remote IoM location.
If it's any help, I have an MBE cable which I'll happily lend you, provided you're willing to pay two-way postage and insurance. If you're interested, just PM me your postal address plus a contact email address too. But I won't be able to send it off until the end of next week as I'm abroad at the moment.
JV