Hi does any member know RPM that the governor should cut in to protect the engine on my 2008 1.4TDi PD car, the reason I ask is that I was talking to a mechanic at my local garage where I take it for the MOT and he said that the way they test the emissions is to get the car to running temperature and the floor the accelerator until the governor cuts in to limit the top engine rpm, this is done 3 times and a average is taken of the 3 readings, and he recommended giving the car good revving  before the MOT to get rid of the rubbish as I only do short journeys, now I have tried revving the engine  to  about 5000rpm which is well into the red and I have not noticed any limiting, so when is this governor meant to cut in to protect the engine?? 

Give your car a good hot run down the road and rev the nuts off it if you really must, but no point sitting revving it.

Is it going to fail anyway, what is wrong with it?

Probably about 5k. But they drop off in power well before that.

Do they do that to all cars? Is that really standard MOT precedure?

Edited 6 February, 201610 yr by fabiamk2SE

They do rev the engine to test diesel emissions, but I've never seen it done 3 times. (I have been present at every MOT all my cars have ever had)

 

There is nothing wrong with your car being able to rev to 5K but if you want to give it a good blowout your better off driving it and getting some heat into it.

They do rev the engine to test diesel emissions, but I've never seen it done 3 times. (I have been present at every MOT all my cars have ever had)

There is nothing wrong with your car being able to rev to 5K but if you want to give it a good blowout your better off driving it and getting some heat into it.

Ah okay. Not petrols then? They dont get redlined on the emissions test?

Edited 6 February, 201610 yr by fabiamk2SE

Ah okay. Not petrols then? They dont get redlined on the emissions test?

For a diesel my MOT man just give it a quick rev and its done. He sometimes put the probe in the dipstick to make sure the engine is up to temperature but unlike most people that tend to drop their car off, I take the car and he does it there and then, they don't have the hassle of having to warm it up.

 

For petrol engines they hold the revs at a set speed and monitor the Lambda reading CO's and HC's. They also check the readings at idle also

 

I'm sure there are some more knowledgeable people on the subject that may correct me if i'm wrong

Edited 6 February, 201610 yr by SuperbTWM

For a diesel my MOT man just give it a quick rev and its done. He sometimes put the probe in the dipstick to make sure the engine is up to temperature but unlike most people that tend to drop their car off, I take the car and he does it there and then, they don't have the hassle of having to warm it up.

For petrol engines they hold the revs at a set speed and monitor the Lambda reading CO's and HC's. They also check the readings at idle also

I'm sure there are some more knowledgeable people on the subject that may correct me if i'm wrong

Very interesting. Thankyou for your input! (:

Any idea what the set RPM is? 3k or something?

I could do with an MOT station like yours .

Cheers.

Very interesting. Thankyou for your input! (:

Any idea what the set RPM is? 3k or something?

I could do with an MOT station like yours .

Cheers.

Yea, somewhere around there, maybe between 2500-3000

 

It is useful knowing who is testing your car. If they don't like something I will go down into the pit so I can see for myself which can sometimes help rather than getting under it myself and wonder where the issue was.

Thanks to you all for your advice, my main concern was that if there was a fault with the governor it could damage the engine when they do the emissions test,  I was trying to find out at what rpm the engine should be limited to,  probably me being a bit paranoid. thanks again for the advice.

Thanks to you all for your advice, my main concern was that if there was a fault with the governor it could damage the engine when they do the emissions test,  I was trying to find out at what rpm the engine should be limited to,  probably me being a bit paranoid. thanks again for the advice.

 

You replicate it as George suggests. 

 

Just make sure its fully up to temperature first.. then maybe let it rev out. 2nd or 3rd gear would be the easiest.