Technical Lumpy bumpy idle

[howardsam95]

Hi all,
Been having this for a while and i am getting a slight lumpy idle. Another issue is the revs differentiating slightly like pulsating.... Any ideas what this could be and right way around fixing it or finding it.
Cheers all,
Help appreciated

Sam

 

[fingers99]

First, do a compression test.

If all cylinders are similar on compression, get back.

 

[souleh]

Might be a dirty Idle Control Valve. Try cleaning the throttle body, there's a guide in the guides section.

 

[howardsam95]

Already cleaned the TB quite extensively. I know its not that unless mine has a fault. I will try a compression test on friday.

Sam

 

[yngprfsnl]

Hello,

I would buy a maxiscan OBDII scanner and throw up the diagnostic code for members to see. I bought one recently and it diagnosed a faulty O2 sensor. When I replaced it I got rid of my lumpy idle problems.

 

[Ziggy122]

hello OP

Have a look at the video on this thread
is this what your car is doing? the rev's bounce up and down like that?

As of yet - still to find a cause im affraid let alone a fix for me....

Ziggy

 

[howardsam95]

My OBDII reader hasnt picked up any codes. How other could i diagnose if this was the issue?

The compression test was consistent between all 4 cyclinders.

And ziggy the issue with mine isnt like that, the revs only bounce around by about 100. My issue only seems to be when hot, but can be slightly noticeable when cold, but more promenant on warn

Sam

 

[fingers99]

100 revs I'd not really worry about. Does it co-incide with the radiator fan coming on?

 

[howardsam95]

Its not the jumping that frustrates me, its the violentness of it. It really seems to jump around sometimes.
It doesnt come on with the fan, just happens every now and then

Sam