My car has been lazy starting from cold for a while now, and lately it has started to idle ever so slightly roughly, but only sometimes and it goes away when I rev it and allow it to idle again.

A couple of months ago I replaced the CTS which cured the issue...for about 2 weeks. I've also cleaned my ICV but do not know whether it is functioning properly or not.

I have changed the plugs and posted a picture of the old plugs which I was told looked healthy.

At the start of the year the car was hit and written off...after fixing it and driving it for a bit it lost coolant and overheated..I assumed this was a leaky rad from being hit so replaced it, and it didn't ever overheat again.

Old air filter was pretty clogged as where I was over summer was very dusty, and the lazy starting did begin in summer. New filter is going in soon, so will see if that helps.

What would be the best way to proceed? What tests should I do to definitively rule out the HG having failed or to detect it? Can I test my ICV with a multimeter? If so, how? If I get a sniff test done, and it says it is fine, will this be a definitive proof that the HG is sealing properly? If I run the car for 15sec before it can heat the coolant and then remove the rad cap and it has pressurised will that indicate that the HG is gone?

Really not sure what to do, but want the car to run properly. Other than slightly rough idle, it pulls fine through the whole rev range.

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61k miles Ph.1 Diablo '6 Project Thread

Run the car up to temperature via driving it, and then allow it to stand overnight.

Take the rad cap off in the morning. There should be no pressure there. If there is, there is something amiss.

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"Supercharged - 454.1bhp/317.5lb/ft"
Peugeot 306 GTi-6
2000 (X), Moonstone

Oh, to add...when I bled the radiator...when the car got right up to temperature the coolant suddenly started bubbling a lot. Am I correct in assuming that until it is up to temperature the coolant sitting in the block is isolated from the rad so no combustion gases would come out through the rad cap opening until the thermostat opened?

If the coolant was being pressurised, basically it shouldn't pressurise the rad until the thermostat opens, correct?

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61k miles Ph.1 Diablo '6 Project Thread

Sniff test being a Co2 monitor in the header tank?

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Red Rallye - Rolling "restoration"

Wishbone Polybushes available

And if the HG is dead and leaking to water, we'll see the hydrocarbon levels rise as the engine is running?

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Red Rallye - Rolling "restoration"

Wishbone Polybushes available

Yes. Generally, the fluid used is a blue colour when you start the process and as hydrocarbons enter it, the fluid goes a green/yellow colour if the HG is going.

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"Supercharged - 454.1bhp/317.5lb/ft"
Peugeot 306 GTi-6
2000 (X), Moonstone

You can't use an MOT emissions tester, a 'sniff tester' is a proper piece of equipment using fluids. It's not something you can just stick in the header tank like you can poke it up the exhaust of a car.

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"Supercharged - 454.1bhp/317.5lb/ft"
Peugeot 306 GTi-6
2000 (X), Moonstone

remove the lip thats formed inside your ICV. the metal valve head on the stepper motor will have squashed an air flow messing up lip in the plastic housing.

bit of emery paper after youve taken it apart and bobs your uncle. fanny's your aunt and maybe your cars idle might fix itself.

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the world is changed by people in sheds

hm...... which means...... either somethigns getting hot and expending messing up a tollerance. which i doubt

or when the ecu switches over to "operating tempreture" ecu running mode, one of the sensors it takes its reading from is on its way out.

have you replaced the o2 lambda sensor yet? this be the main one after your engine gets up to temp

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the world is changed by people in sheds

No. I haven't noticed a drop-off in fuel economy at all so the O2 sensor seems to be doing its job.
I did suspect a sensor for quite a while. I'd like to test them all with a multimeter I'm just not sure exactly how.

I really must emphasise that the "running rough" is ever so slight and that passengers don't even notice it. I can just see the needle twitching ever so slightly and can feel it a tiny bit. It is definitely there though, when it does occur.


I think the starter motor is fine, it is cranking just as fast as it should from the sound of it, just it is cranking for too long when cold and sometimes needs throttle encouragement. My air filter was very dusty from back home and that's being changed.

As for sensors, like I said above, I'd like to test sensors that could potentially be causing this I'm just not sure how. Can anyone give me an idea of how to do this? I've already replaced the CTS. When I put a new airbox in I might try resetting the ECU just to see what happens.

I'd still like to get this sniff-tested though as that'll tell me for sure.

So anyone know how to test any sensors that might be the problem? Edit: just found the FAQ

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61k miles Ph.1 Diablo '6 Project Thread

Certainly sounds like it, as I said above if you continue to drive it you are risking the head being totally f**ked and not only that but if your oil is being affected doing damage to the bottom end hence It's no coincidence a lot of people suffer bottom end failure shortly after having headgasket repairs.

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Ryan

buy some tools and get busy, it won't fix itself!

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306 rallye reproduction decals (full sets/individual decals) | 306 b-pillar textured vinyl weatherstrips
306 slam panel esso stickers | 306 yellow / orange / pension fund red side door badges
gti6 inlet manifold badges | 306 rear boot badges (p2/p3)
winner of Extraction of toys from prams with outstanding vigour award 2009 [source: gti6 owners club]

If your fairly handy with spanners have a go yourself, although it may be a bit daunting they aren't that hard to do. If you can do it yourself you'll be looking at about £300 to fix it.

Edit: just seen your reply so I'd say do it, only 'special' tool you will need really is a good torque wrench

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Ryan