Uneven Acceleration

[mlkey]

Hi,

 

Newbie poster here. Picked up my C5 2.0 110 HDI today, a 52 plate with 82k on it. I have noticed an issue under acceleration, no idea how to describe it but will try.

 

When accelerating gently I notice sometimes there is like a pulsing of power, like accerate one second, hold back one second, accelerate one second, hold back one second. Its almost like your dabbing the brakes very gently for a second at a time, or like an aircon compressor putting load on the engine.

 

I have tried with the air con off, also it does not seem to do it all the time. Not sure if I am imagining the next part.. When I collected the car it did not have much fuel in, I drove the 40 miles home and did not notice this problem. I then filled it up, and it was shortly after that I started tp notice the problem.

 

Grateful for any assistance anyone can offer.

 

Mike.

[mlkey]

Me again,

 

I will post this here in case anyone else comes across the same problem. It was the EGR valve. I disconnected the vacuum pipe, and blanked it off at the solenoid, it has been as good as gold since, and went straight through the MOT. Covered 9000 miles since this, getting mid 50's to the gallon with mixed roads.

 

Hope this is of use to someone.

 

Hi,

 

Newbie poster here. Picked up my C5 2.0 110 HDI today, a 52 plate with 82k on it. I have noticed an issue under acceleration, no idea how to describe it but will try.

 

When accelerating gently I notice sometimes there is like a pulsing of power, like accerate one second, hold back one second, accelerate one second, hold back one second. Its almost like your dabbing the brakes very gently for a second at a time, or like an aircon compressor putting load on the engine.

 

I have tried with the air con off, also it does not seem to do it all the time. Not sure if I am imagining the next part.. When I collected the car it did not have much fuel in, I drove the 40 miles home and did not notice this problem. I then filled it up, and it was shortly after that I started tp notice the problem.

 

Grateful for any assistance anyone can offer.

 

Mike.

[DaveHerns]

So does the EGR valve not serve any useful function ? I would have thought your emissions would be too high with it disconnected ?

[Randombloke]

So does the EGR valve not serve any useful function ? I would have thought your emissions would be too high with it disconnected ?

 

The EGR reduces emissions, and new vehicles are equipped with them to ensure they comply with legislation and type approval that they must adhere to.

 

The emissions tests in the MOT are usually not as stringent as the regulations for new vehicles, so it may be that the car will still pass the MOT with the EGR valve bypassed. It will also produce slightly more power.