S40 (New) Engine 2.0D : S40 Starting and Rough Idle problem. Intermittent.

[Lewy-]

I've recently had an intermittent fault return on my Volvo S40 Diesel.
The fault had occured once before, then dissapeared by itself, but the other day returned and has continued on an intermittent basis.

The problem is that when trying to start the engine, it turns over and fires, but soon stalls.

However, if the engine fires, it runs very rough and at low RPM. As well as this, there is also black smoke from the exhaust pipe.

Could anyone give me an insight as to what could be causing this, and why it only happens on occasion?

I knew that black smoke usualy means running too rich, but this does not explain to me why the engine doesnt start yet sometimes does. And have never heard of this kind of problem being caused by a rich mixture.

Thankyou,

Lewis

[Lewy-]

Why can no one reply to this lol

[Lewy-]

Still no help

[Clan]

it is worth going for a new plastic throttle body , the flap can stick and cause exactly this . they are about £60 for the single one , probably more if you have a euro 4 twin throttle . Yes black smoke is too much fuel OR non enough air !

[Lewy-]

Originally Posted by Clan

it is worth going for a new plastic throttle body , the flap can stick and cause exactly this . they are about £60 for the single one , probably more if you have a euro 4 twin throttle . Yes black smoke is too much fuel OR non enough air !

Hey thanks for the help.

But i thought my S40 Has a hot wire air mass meter...so no flap! :S
Any advice? lol

[Clan]

Yes you still have an Air Mass Meter . The throttle flap shuts when you turn the engine off to prevent shuddering when you switch off .

[Lewy-]

Originally Posted by Clan

Yes you still have an Air Mass Meter . The throttle flap shuts when you turn the engine off to prevent shuddering when you switch off .

Okay thanks

Im probably just confusing myself....but is the similar OR the same thing to a throttle butterfly that petrol engines use to meter the air flow?

Thanks once again.

I shall take a look at the throttle flap.

Any further advice on where its located or how to test?

Thanks once again!

[Clan]

its similar to a petrol throttle flap but plastic . it doesnt meter the air in a petrol just allows more or less air in to regulate the power . Anyway it is the unit between the big boost pipe and inlet manifold with some sensors on and a vacuum operating capsule . remove the pipe and press the throttle closed against its fairly strong spring firmly , and any tendancy to stick then i would fit a new one .

[Lewy-]

Thanks once again for the good help!

Much apprecieated.

[MPlb21]

Hi

I've had this problem a couple of times usually when it's cold or the car hasn't been used for a week or so.

If it is a sticking (plastic) throttle body is there anything on it that can be lubricated to try to prevent it happening again or does it need replacing?

Whereabouts is this part of the throttle? Is it easy to locate or will it mean taking the engine to pieces?

Thanks