Technical 2013 Panda 1.2 rough idle and failing emissions test.

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Technical 2013 Panda 1.2 rough idle and failing emissions test.

Mot emmisions test machine reading over 1.4 not a large leak of air into exhaust?

The highest reading I have previously seen was 1.2 caused by a 25mm diameter hole and a split , both in the middle pipe.

But I guess a smaller hole in a low pressure region(hadn't considered that) could have a similar effect .

I do hope we get some pictures so we can see for ourselves

Looking forward to the pictures too. 1.4 may be huge value, but this car sure hasn’t got a 1”-2” Hole in the exhaust, as we’d All have heard it coming by now. Let’s see what the issue looks like when we have further info. Forum diagnosis like this can be very interesting!
 
FYI
The rear silencer (factory spec.) Is tilted forward slightly.. and has tiny (@3mm) hole as a drain

So seeing damp..or drips isnt conclusive


Is the back box peeling like an onion..?

Thats what I generally see :eek:

back box looks in good condition, pretty much no rust. the rest of the exhaust (pipe) is rusty.
 
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I'd put my money on that the exhaust is Not the problem. With a figure as high as that it would sound like a formula 1 car if it was exhaust related. Look for low fuel pressure, air leaks round the inlet manifold, a partially blocked injector or the issue with the carbon canister, over filling with fuel can damage it.
 
I had the same issue with a new Skoda Favorit GLXIE on its first MOT it was always a little hesitant, the dealer could not find the fault and eventually gave up. I found the spring in the fuel pressure regulator to be broken at its lower part, a new spring cured the issue. Hesitation cured too, all down to low fuel pressure.
 
I had the same issue with a new Skoda Favorit GLXIE on its first MOT it was always a little hesitant, the dealer could not find the fault and eventually gave up. I found the spring in the fuel pressure regulator to be broken at its lower part, a new spring cured the issue. Hesitation cured too, all down to low fuel pressure.

Failed 1st MOT on emissions.. thats not good.

What were the figures?

I know some panda TAs have issues when COLD
 
A very high mot test lambda calculated reading means massively excess oxygen in exhaust gasses

Remember the mot test co was low and a pass and the hc was low and a pass.
These readings point to the fuel air ratio in the engine being correct.
 
A very high mot test lambda calculated reading means massively excess oxygen in exhaust gasses

Remember the mot test co was low and a pass and the hc was low and a pass.
These readings point to the fuel air ratio in the engine being correct.

In fact, CO and HC numbers were precisely ZERO in each case - too good to be true? I've never seen any zero's for HC or CO on any of my previous MoT's, so something might not be completely in order with that MoT testing kit maybe? Smells fishy I think.....
 
back box looks in good condition, pretty much no rust. the rest of the exhaust (pipe) is rusty.
Is this observation with the car on ramps or on the ground?

For clarity If your engine keeps running with tail pipe completely blocked (damp rag ,glove , potato , whatever) then the exhaust is likely holed somewhere and you are more my likely to hear a leak by hissing or blowing.

Everyone is guessing or assuming what your car sounds like. Do you know if it sounds loud or blow? It's ok to say if you don't know and dont have any experience of blowing exhaust sounds.

Many thanks

Jack
 
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On the Favorit the HC was zero as well and the lambda was high, too long ago to remember the actual figures, they replaced the sensor and went through the exhaust and even tried a new CAT. It must have had a gallon of injector cleaner too. Actually I'd complained to Skoda about the hesitation from new with no success, Skoda under VW had rubbish support at the time. A friend loaned me a fuel pressure gauge and it was around 20% low.
 
Is this observation with the car on ramps or on the ground?

For clarity If your engine keeps running with tail pipe completely blocked (damp rag ,glove , potato , whatever) then the exhaust is holed somewhere.

Everyone is guessing or assuming what your car sounds like. Do you know if it sounds loud or blow? It's ok to say if you don't know and dont have any experience of blowing exhaust sounds.

Many thanks

Jack

It's important to get a good seal on the exhaust outlet to stall an engine. Modern systems with an ECU will compensate when you try to stall an engine by upping the fuel delivery, this can be by trying to move of at low revs in second gear or by choking the exhaust. Go and try to stop another Panda that way, it's not easy!!!!!
 
In fact, CO and HC numbers were precisely ZERO in each case - too good to be true? I've never seen any zero's for HC or CO on any of my previous MoT's, so something might not be completely in order with that MoT testing kit maybe? Smells fishy I think.....
Omg thanks Rings,

I didn't spot that at all , silly me just looking at pass fail.

It is almost as if the test probe wasn't in the exhaust gasses at all isn't it?

Very fishy indeed.

Everything I have said till now is null and void .

Thanks for the peer review Ringa.

Question for op are any exhaust fumes coming from the tail pipe at all?

Does the car sound quiet at tail pipe?

May have hissing sound?

Can you feel exhaust gasses exiting tail pipe?
 
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Is this observation with the car on ramps or on the ground?

For clarity If your engine keeps running with tail pipe completely blocked (damp rag ,glove , potato , whatever) then the exhaust is holed somewhere.

Everyone is guessing or assuming what your car sounds like. Do you know if it sounds loud or blow? It's ok to say if you don't know and dont have any experience of blowing exhaust sounds.

Many thanks

Jack


Thread title states poor running..

In itself a 'minor' exhaust leak shouldnt be that big a contributor..

Like you say.. probably not seeing the bigger picture here

Often oil and water temps will play a part in diagnosis..

Did we see any of this data?
 
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Coolant is filled and no air in system.

I have to note also that the issue is not there on a cold start and starts when the engine starts to get warm and the revs drop to normal idle, which at the moment is around 770 rpm.

Thanks..

Not there when cold.. still pointing to something other than JUST the exhaust


Do you still get the MIL ?

Charlie
 
It's important to get a good seal on the exhaust outlet to stall an engine. Modern systems with an ECU will compensate when you try to stall an engine by upping the fuel delivery, this can be by trying to move of at low revs in second gear or by choking the exhaust. Go and try to stop another Panda that way, it's not easy!!!!!
Ok Murphy I have heard you.


Ringa has pointed out massive flaw in mot emmisions report
So we have to go back to square one as Charlie is suggesting
 
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Thanks..

Not there when cold.. still pointing to something other than JUST the exhaust


Do you still get the MIL ?

Charlie
If the mot centre did put the probe in exhaust and got those readings

It is consistent with the exhaust being completely block somewhere ahead of the tailpipe . The exact opposite of what I previously thought , wierd.

Op does the car drive with very poorly with low power?
 
Interesting looking at the RPM they used on the test. This is the official gov document that describes the procedure (see page 5) and lists the test criteria (see page 47 in the annex for the specific values for a 2013 Panda with 1.2 69bhp engine). It says there the RPM should be between 2300 and 2500 for the fast idle test, and oil temperature minimum 93C. I don't know how much difference it would make doing the test at the higher revs they used... (if any). They show there 'natural idle' should be between 660 and 760 rpm (which yours was), not the 500-1500 limit shown on your test results. Did they have the tester set up for the correct car??
https://assets.publishing.service.g...-standards-for-road-vehicles-19th-edition.pdf
Back to my previous comment, a catalyst should convert all CO to CO2 - so a 'perfect' reading is zero. As the catalyst ages and degrade, the value will creep up. The figure fro HC should ideally also be zero, and no un-burned fuel or oil should get past the catalyst. (One reason whty you no longer see older cars blowing blue oily smoke -- partly because oil seals are better, but mainly because Cat's are converting it all)
 
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