182 Misfire and Rattle

[si_hartlepool]

If the car has been stood for a while (over a few hours usually) i get a hesitation under acceleration and a misfire if i lift off or change gear. This last about 2 minutes on first start up only, then it runs fine. I've been told this is pretty normal as they over fuel when cold however, it has only started in the last 2 months.

When the car starts driving normally (after 2 minutes approx) there is a rattle on acceleration. It only occurs on anything over half throttle and starts around 2k revs. It sounds sort of like an exhaust blow with a metallic 'tinkle' at the same time. I've changed the cat to manifold gasket as i thought this was blowing and causing it, but it hasn't made a difference. The exhaust now isn't blowing at all.

I've researched this rattle for months and had no joy solving it. Do i have to live with the noise and the misfires or has anyone experienced similar symptoms?

I would really appreciate some advice.

Cheers,

Simon

 

[jonzii]

Your hesitation problem sounds like what mine used to do. A new O2 sensor cured it!

 

[si_hartlepool]

Your hesitation problem sounds like what mine used to do. A new O2 sensor cured it!

Was it only hesitating when it was first started?

 

[Faboka]

Does after about 2 minutes it goes to normal like a flick of a switch?

That's the issue I'm having. Took some logs of the O2 sensor today and to me it looks wrong which would indicator a new sensor.

 

[si_hartlepool]

Does after about 2 minutes it goes to normal like a flick of a switch?

That's the issue I'm having. Took some logs of the O2 sensor today and to me it looks wrong which would indicator a new sensor.

Yeah

Is this the pre cat one you're talking about?

 

[davemittell]

If its from cold then o2 sensor won't be doing much as ecu will be in open loop after it warms up a bit ecu will go into closed loop and start adjusting the mixture, this may be what you are experiencing as the improvement. Is the 02 sensor switching once warm?
Have you checked temp sensor readings? if faulty then the car doesnt know if its hot or cold therefore could give similar issues.

 

[Faboka]

Yeah

Is this the pre cat one you're talking about?

Yeah. Been meaning to swap it with post but it's a little tight to undo

 

[si_hartlepool]

If its from cold then o2 sensor won't be doing much as ecu will be in open loop after it warms up a bit ecu will go into closed loop and start adjusting the mixture, this may be what you are experiencing as the improvement. Is the 02 sensor switching once warm?
Have you checked temp sensor readings? if faulty then the car doesnt know if its hot or cold therefore could give similar issues.

It's only when cold, its fine when warm.

How do i check temperature readings?

 

[CR1S]

Mine does this, I just ignore it tbh and wake people up haha

 

[davemittell]

with diagnostic equipment is the easiest way. If not you could check resistances/ voltages being produced by the temp sensor although difficult to explain unless you know what you are doing.

 

[davemittell]

Just thinking about this the sports do always idle lumpy for emissions purposes.
However you do say its only done it for the last few months, have you done the obvious like checked/changed the plugs etc?

 

[si_hartlepool]

I Will be checking the plugs tomorrow and will report back

 

[jonzii]

Was it only hesitating when it was first started?

Yeah, would disappear within a couple of minutes.

 

[si_hartlepool]

I've checked the plugs and coil pack. They're both fine.

What's next? Lambda?

 

[BurnyC]

The rattle with metallic 'tinkle' noise is exactly what I've got pretty much - I've narrowed it down to the join between the cat to the rest of the system. I had it bodged and it went away for a few weeks, came back again. This part of the system and the join you've already done are the common ones.

 

[si_hartlepool]

The rattle with metallic 'tinkle' noise is exactly what I've got pretty much - I've narrowed it down to the join between the cat to the rest of the system. I had it bodged and it went away for a few weeks, came back again. This part of the system and the join you've already done are the common ones.

I've ordered some high temperature silicone to try and seal this joint properly.

Thanks for the heads up. Hopefully this will sort it.

 

[si_hartlepool]

Silicone has done the trick No blowing or misfiring up to now!

Thanks everyone

 

[johnofox]

Silicone has done the trick No blowing or misfiring up to now!

Thanks everyone

Did this ever come back or was it fully sorted? I literally have the same problem but it has come in stages... originally the high-pitched exhaust type noise from when I bought the car, last month or so the emissions light flashed occasionally when idling (more so before the car was warm, but sometimes when in heavy traffic for a long time) and now it is misfiring and losing power until fully warmed up.

In danger of doing the old "change everything, fix nothing" routine here...!

 

[si_hartlepool]

It came back....the cat to centre sleeve wasn't sealing as it was sitting in a V shape; as apposed to sitting straight.

In the end i got sick of it and fitted a decat Haha, now there is no problems at all!

I don't know what would have fixed it if i left the cat in. It seemed too heavy at the join to the centre section and that's why it was sagging in a V shape. Perhaps it was because the milltek is heavy as it has 3 silencers from the cat back.

Hope that makes sense...

 

[si_hartlepool]

It still pops when cold but i believe that's normal.

 

[johnofox]

It still pops when cold but i believe that's normal.

Mine's always popped a little too. I got a cheap scanner on it and it said "multiple/random cylinder misfire" and 02 sensor fault. I cleared these and it changed to "cylinder 3 misfire". Wonder if it might be coil pack/injector and the O2 sensor could be an old code.