General lumpy tickover

[iainbja]

Hi can anyone shed any light on this problem with my Seicento Sporting. It's a 2000 car 60k mile runs well starts spot on but a tickover it's a touch lumpy not terrible but not totally even. At the rear you can hear it popping a touch in the exhaust. As soon as you touch the gas it's perfect and it does not effect the running on the road. Tick over is steady at 750 revs on the rev counter.

Cheers Iain

 

[rallycinq]

Remove and replace each plug lead in turn and note which, if any, cause no change.

Cheers

SPD

 

[Madmike]

I have this on my Cinq Sporting also
As Iain says, it's not terribly bad, once I give it a rev it's fine, and it never causes issues, BUT, I'm just curious as to what causes it?? I'd imagine myself it's almost *bordering* on running rich or does that sound ridiculous?

Anyway, rallycinq, you mentioned trying the leads. I will give this a shot, but I'm curious...... what will this prove or disprove? I have just fitted new plugs recently and it's the same as it was before. Would it be related to coils or leads?

 

[clock34]

thought they always ran a tad lumpy anyway... expecially in traffic with the fan on or at night with the lights on.

 

[rallycinq]

I have this on my Cinq Sporting also
As Iain says, it's not terribly bad, once I give it a rev it's fine, and it never causes issues, BUT, I'm just curious as to what causes it?? I'd imagine myself it's almost *bordering* on running rich or does that sound ridiculous?

Anyway, rallycinq, you mentioned trying the leads. I will give this a shot, but I'm curious...... what will this prove or disprove? I have just fitted new plugs recently and it's the same as it was before. Would it be related to coils or leads?

Cinq sporting is entirely different to a 2000 Sei.

The problem is related to ignition or compression, there is only one injector.

By removing and replacing each plug lead in turn will identify which cylinder 'missing'.

Once you have identified the cylinder(s) you can take the diagnostic further, by swapping the lead from a known good cylinder and see whether the 'miss' stays in the same place or not.

Assuming it does, swap the coils, check again, and so forth until you get an answer.

Report back.

Cheers

D