so my lambda is titanium and was reading 0.45 so is very rich, this is why it is missing, just as i thought. unless the readings are getting muddied by the un-burned fuel on that missed cycle
mot woes
- Thread starter littlefeller
- Start date
Have you carried out a compression test Jason?
Tony.
Tony.
My OH's Mini had a misfire on cylinder 3, sometimes on a couple of cylinders which threw up a codes for the lambda and camshaft sensors. Changed both of these and it made no difference, turned out to be the spark plugs causing the misfire and throwing up a couple of incorrect codes.
no compression test yet, i would imagine it would be fine when warm, low when cold, i dont think the misfire is compression related, unless i have a slight valve problem. the rough cold start is normally sorted with an oil change, currently done about 7000-8000 miles on this oil, will change it before the test. it doesn't solve the misfire though but does improve it slightly (or im just imagining it). i have swapped the plugs, old plugs were a good colour and still working fine.
@Faheem here ya go, not so bad as removing the head. found this, this is our issue.
Situation 2
Binding HVA element.
Cause
An HVA element which is binding (element stuck in the extended position) will not allow a valve (intake or exhaust) to seat properly causing valve seat leakage.
This type of HVA failure may not cause a tapping/rattling noise but the customer complaint may be, "engine runs rough during the warm up phase and runs good when warmed up" and/or the "Check Engine" lamp is on.
If the "Check Engine" lamp is illuminated due to a binding HVA element(s) one or more misfire fault codes may be set in the Engine Control Module (ECM/DME).
Note: Basic troubleshooting should be performed First before checking for a binding HVA element to eliminate all other possible factors/components which could set the misfire faults such as low fuel level, a faulty spark plug, etc.
Troubleshooting Tips:
• If there is a binding HVA element in one or more cylinders as described above a misfire fault can typically be reproduced in the affected cylinders) by duplicating the conditions in which the misfire occurred according to the DME/ECM fault code description i.e., at engine temperature = X, engine speed = X, etc.
• A binding HVA element which is causing a misfire in one specific cylinder will not "move" to an other cylinder and will always cause a misfire fault in the affected cylinder.
• Performing the "Smooth-Running" test (found in the DME control unit functions section of DIS) will assist in pin pointing a cylinder with a binding HVA element.
A cylinder with a binding HVA element will indicate a high reading when compared to the other good cylinders.
• Since a binding HVA element may in some cases be intermittent (engine only runs rough when cold) if a cylinder leak down check is used for troubleshooting this should be performed when the problem exists, for example: compare the cylinder leakage rates to each other with a cold engine to determine the cylinder with the extreme leakage rate.
A cylinder with a binding HVA element will indicate a leakage rate above 15%.
Remove suspected HVA elements and visually inspect.
• A binding HVA element will typically have a high pressure piston (located in the centre of the HVA element body) which extends out approximately 3 mm further when compared to the other HVA elements removed from the cylinder head.
Replace any binding HVA element(s) and check others for extreme wear (deep grooves, scratches, etc.) which may also need to be replaced.
Note: Always reinstall used HVA elements in the same bore which they were removed from. This prevents possible binding due to different wear patterns between the bore in the HVA housing and HVA element.
Situation 2
Binding HVA element.
Cause
An HVA element which is binding (element stuck in the extended position) will not allow a valve (intake or exhaust) to seat properly causing valve seat leakage.
This type of HVA failure may not cause a tapping/rattling noise but the customer complaint may be, "engine runs rough during the warm up phase and runs good when warmed up" and/or the "Check Engine" lamp is on.
If the "Check Engine" lamp is illuminated due to a binding HVA element(s) one or more misfire fault codes may be set in the Engine Control Module (ECM/DME).
Note: Basic troubleshooting should be performed First before checking for a binding HVA element to eliminate all other possible factors/components which could set the misfire faults such as low fuel level, a faulty spark plug, etc.
Troubleshooting Tips:
• If there is a binding HVA element in one or more cylinders as described above a misfire fault can typically be reproduced in the affected cylinders) by duplicating the conditions in which the misfire occurred according to the DME/ECM fault code description i.e., at engine temperature = X, engine speed = X, etc.
• A binding HVA element which is causing a misfire in one specific cylinder will not "move" to an other cylinder and will always cause a misfire fault in the affected cylinder.
• Performing the "Smooth-Running" test (found in the DME control unit functions section of DIS) will assist in pin pointing a cylinder with a binding HVA element.
A cylinder with a binding HVA element will indicate a high reading when compared to the other good cylinders.
• Since a binding HVA element may in some cases be intermittent (engine only runs rough when cold) if a cylinder leak down check is used for troubleshooting this should be performed when the problem exists, for example: compare the cylinder leakage rates to each other with a cold engine to determine the cylinder with the extreme leakage rate.
A cylinder with a binding HVA element will indicate a leakage rate above 15%.
Remove suspected HVA elements and visually inspect.
• A binding HVA element will typically have a high pressure piston (located in the centre of the HVA element body) which extends out approximately 3 mm further when compared to the other HVA elements removed from the cylinder head.
Replace any binding HVA element(s) and check others for extreme wear (deep grooves, scratches, etc.) which may also need to be replaced.
Note: Always reinstall used HVA elements in the same bore which they were removed from. This prevents possible binding due to different wear patterns between the bore in the HVA housing and HVA element.
All very interesting. Are you sure that a good run would not sort this?
probably, coupled with an oil change, will be changing the oil sat morning and going on the Cotswold cruise sun (assuming mot is ok) so hopefully this will sort the cold starts (be summer soon so it will disappear anyway)
I think the cold start issue is a different problem (most likely the one above) to my misfire, the misfire is something else I think.
Fingers crossed for you.
Heres hoping
@littlefeller thanks for this. Are you sure that the misfire is not in any way connected to the cold start issue? I seem to have both when this issue occurs and whilst I don't have inpa, a standard code reader shows codes for the oxygen sensor and multiple misfires. The zeds driven everyday but prior to the oil change no matter how hard it was driven it didn't make a difference to the starting issue and gradually became worse until the oil was changed.
it could be related, but does your misfire go when you change the oil? i dont think mine did, though i will find out tomorrow. The lambda code seems to be related to the misfire codes, i dont get one without the other. the misfire code is thrown because of the measurements that are taken for each cylinder and compared to other cylinders hence the smoothness test in inpa once it goes out side a pre-set tolerance you get the misfire codes followed by the Lambda code, i know this because of the time these codes appear are the same, so same time, same engine speed and same engine temperature. they are all related, my misfire i can hear on idle doesn't throw a code for some reason, maybe it has a min rpm. although i cant be absolutely certain on this as it will only display the last code stored and not all of them, so for instance it will say error frequency 8, so i assume it has thrown this code 8 times but only displays the time of the last one. it would be nice to think this idle could be sorted with a play around with the lifters though. maybe this is what actually happens, BMW remove the head to re cut valve seats, but in order to do that you must remove the lifters, maybe they are repairing the misfire without even realizing it. will swap oil tomorrow and post findings.
might be worth using a flushing oil first to clean the lifters
my thoughts on this issue and why i dont think the two are related is this - im thinking the cold start issue is maybe related to some kind of engine breather issue, that is when stood and goes cold the air inside the engine cools and contracts thus drawing oil out of the lifters, it takes a few seconds on start up to replenish this oil, old oil is thinner so this happens more so than on new oil, thinking aloud what if i try a higher viscosity oil, on the last change i used 0w30, this now needs changing much sooner that the 10w30 (or was it 5w30) i used last time. maybe the misfire is sticking lifters while the cold start is no oil.
I think you will find that new oil is thinner than old oil
it thins out first, then thickens up as the miles pile up.
@littlefeller originally I did an oil change on the 17th December 16, I didn't use an engine flush nor any valve lifter treatment. I used 10w40 - as I had been doing for the past year and a half. Misfire remained after the oil change.
However, after Tony's suggestion I changed the oil again in early February, this time using an engine flush and the valve treatment and the misfire has gone, only on the odd occasion does it hesitate a little on a cold start.
However, after Tony's suggestion I changed the oil again in early February, this time using an engine flush and the valve treatment and the misfire has gone, only on the odd occasion does it hesitate a little on a cold start.
Took my oil out this eve, defo thinner than the oil going in, but it was warm and I have gone for a 5w30 this time ( had some in the shed) it may frost tonight so the morning will tell.
Well that's a suprise , the oddest thing has just happened, ok so I thought I would drive down the lane and back to get the new higher visosity oil circulating? Left it idling for 2 min first then when I got to the end of the lane ( about 8 min in total), temp gauge is now rising as it should what the heck is that all about. I have swapped it over from 0w30 to 5w30 and it seems to have fixed my cooling issue .
@t-tony ?
@t-tony ?
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could this oil have been the cause of all my mot issues?