Dieselman
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Can you check it on the car battery to see if it reads ~12v as some of those readings are strange.
Try the MAS and Lambda on the same scale as the 12v test if that appears OK, just as a test.
Just thinking about it, it would be worth performing a driving check on the MAS as it could be that causing the high idle lambda reading but then causes lean condition under high airflow.
If you recall I thought the idle reading was high, I still think it is.
Any idea what happened with the lambda if the revs are raised above idle but in neutral.?
If they steady at 0.2/0.8v then the lambda is probably Ok and it points to the MAS again.
Try the MAS and Lambda on the same scale as the 12v test if that appears OK, just as a test.
Just thinking about it, it would be worth performing a driving check on the MAS as it could be that causing the high idle lambda reading but then causes lean condition under high airflow.
If you recall I thought the idle reading was high, I still think it is.
Any idea what happened with the lambda if the revs are raised above idle but in neutral.?
If they steady at 0.2/0.8v then the lambda is probably Ok and it points to the MAS again.
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gina2201
MB Enthusiast
Ok, I have a confession to make. The odd readings may have something to do with the fact that my voltmeter has different settings or symbols, two of which with a V and a different symbol above each. After testing the battery with the initial setting with a result of 26 changed the setting and it dropped to 12v !
Retried the lambda sensor test and got different figures than before.
At idle it read 0.7v
When driving steadily it went from 0.3v - 1.1v and when foot off accelerator it could be fairly regular at 0.34v. Even when it did misfire it stayed at this figure.
Retried the lambda sensor test and got different figures than before.
At idle it read 0.7v
When driving steadily it went from 0.3v - 1.1v and when foot off accelerator it could be fairly regular at 0.34v. Even when it did misfire it stayed at this figure.
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Dieselman
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Which figure.? 0.34 (a bit low but would be Ok for over-run) or 0.7, or switching.
It should switch at 1 second intervals between high and low. The idle figure seems a little high, but then so is the highest figure so that is probably meter error.
If you take 0.2v off each figure you have 0.5v at idle, and switching between 0.1 and 0.9, which means the sensor works OK.
It's strange that there was no change when misfiring...hmm..
It should switch at 1 second intervals between high and low. The idle figure seems a little high, but then so is the highest figure so that is probably meter error.
If you take 0.2v off each figure you have 0.5v at idle, and switching between 0.1 and 0.9, which means the sensor works OK.
It's strange that there was no change when misfiring...hmm..
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Are you sure it's a missfire?
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gina2201
MB Enthusiast
Suppose the meter could well be inaccurate. It might well be an idea to book it into an indy and I would after changing/having a go at most things.
The readings did switch between high and low at 1 second intervals. Quite consistent! The idle value didn't alter even when revving (this correct?)
I have been given a recommendation for a garage by my local GSF branch for a diagnostic/any work.
The readings did switch between high and low at 1 second intervals. Quite consistent! The idle value didn't alter even when revving (this correct?)
I have been given a recommendation for a garage by my local GSF branch for a diagnostic/any work.
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gina2201
MB Enthusiast
That's what I think it is, what else might make the car hold back such as this? I know it would be alot easier if you could drive it and experience it for yourself.
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Holding back?
Thats not a missfire.
Describe it as best you can
Thats not a missfire.
Describe it as best you can
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gina2201
MB Enthusiast
Ok,from cold (especially when I leave for work in the morning 6am) the car even in 1st and 2nd gear doesn't go forward when you put your foot down. It makes a noise as if it wants to go but something is holding it back, almost like go/stop/go/stop. I have to let off and apply the accelerator alot more steadily/progressive to get an even drive.
It often 'misses' or does this when accelerating from 2nd/3rd/4th but not if you apply the accerlerator slowly and gently. You can drive it fine then. But I think it must be running not 100% or as quick as it could be.
I did give it a good drive earlier and from 1st through to redline then 2nd it didn't misfire but it was more a progressive pressure on the pedal rather than straight to the floor. If that makes sense?
It often 'misses' or does this when accelerating from 2nd/3rd/4th but not if you apply the accerlerator slowly and gently. You can drive it fine then. But I think it must be running not 100% or as quick as it could be.
I did give it a good drive earlier and from 1st through to redline then 2nd it didn't misfire but it was more a progressive pressure on the pedal rather than straight to the floor. If that makes sense?
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Yes it does.
That is classic air mass sensor issue symptom. I think you may have to try one on there or get it diagnosed.
Are all the intake pipes secure?
That is classic air mass sensor issue symptom. I think you may have to try one on there or get it diagnosed.
Are all the intake pipes secure?
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gina2201
MB Enthusiast
As far as I'm aware but wouldn't hurt to check.
Someone I know also has a w202 C230k (silver one in my sig!), see if I can persuade him to let me borrow it....
Dieselman
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This is sounding more like the MAS again as the Lambda appears to work OK. (it switches with sensible figures).
When you tested the MAS was the meter set correctly.?
When you tested the MAS was the meter set correctly.?
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If its ok? It might be iffy too?
Check the intake pipes too.
Check the intake pipes too.
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gina2201
MB Enthusiast
Ummmm no!
I will do that tomorrow as it got too dark this evening but seems relatively simple to check.
Dieselman
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Aha..Leading us up the garden path....
Try it on a drive to get the maximum figure it can give. Can you remember the figures I suggested..?
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gina2201
MB Enthusiast
Aha..Leading us up the garden path....
Try it on a drive to get the maximum figure it can give. Can you remember the figures I suggested..?
Wasn't it 4.5/4.8?
I'll have to go back through the thread!
Dieselman
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LOL..yeah..
2v at idle rising to 4.5-4.8v at full revs.
2v at idle rising to 4.5-4.8v at full revs.
