Sluggish xu10j4rs

[sherman306]

My xsara vts just feels abit flat sometimes and.doesn't pick up like I think it should any ideas?

[willJspears]

How do you drive it? (if you get what I'm saying). The torque band doesn't come in until about 4k. Under that they're not really that quick.

[Piggy]

Likely to be a sensor issue, perhaps a dying TPS or lambda.

That or maybe it could do with a good service? When were plugs last changed?

[RetroPug]

Is it bogging down, and does it go away once it is up to temperature?
If there are flat spots in acceleration at low revs it could be the TPS or the CTS, especially if it goes away once warmed up.

[sherman306]

It feels.intermittent and some.times when I'm in neutral you rev it and just revs up like.a 1.2 then other times revs up real nice

[Niall]

Cts or lambda is my bet.

[sherman306]

Cts? Coolant temp?

[Niall]

Yep

[sherman306]

Ah cool thanks for the info guys

[RetroPug]

Does it clear once the car is up to temperature?
Normally bogging down when cold is due to the car running too lean for the lower temperatures, which is either the coolant temperature sensor (you guessed correctly), or possibly the throttle position sensor (TPS) not reading correctly when you're at part throttle.

It is possible to test these sensors with a multimeter for correct voltages etc.

Sometimes an idle control valve (ICV) on its way out makes the car bog down and low throttle and when rolling in gear.

[Ruan]

Had the cambelt done recently?!

Seen so many J4RSs perform like dogs after a cambelt change due to them not knowing how to set the timing correctly...

[sherman306]

I don't know about the timing belt but as it's not a consistent problem I wouldn't of thought it was that and how do I test them?

[sherman306]

Right had the snapon ethos connected up to do some live data and all sensors are performing ok apart from the second lambda sensor is showing 0.00 but I wouldn't of thought that would be causing the sluggishness as it's just a diagnosis sensor not linked to mixture?

[luke306rallye]

There's only one lambda sensor that's why.

[sherman306]

2 mate I've seen them with my.own eyes

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Post cat and pre cat

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Might add the engine Is actually in.a xsara vts but it can't be much diff same engine code and all

[powerandtorque]

The engine management is different on Phase 2 Xsara VTS's compared to the earlier Phase 1 Xsara's and 306's. It's multiplex with 3 plugs on the ECU and amongst other things has two lambda's as mentioned.

The 2nd lambda is there to check the performance of the CAT - fuelling is controlled by the 1st lambda.

The basic engine is fundementally the same though, as are the majority of the sensors.

[sherman306]

So the second lambda fault wouldn't cause my sluggish running?

[Niall]

It could be depending on how these ECUs work. Most with 2 lambdas purely use the second one to see if the cat is working and if not flag up a fault. Others if they detect the cat isn't working then they will still try to correct the emissions as much as possible.

[sherman306]

It's a 4 wire one if that makes any difference

[Niall]

It's a 4 wire one if that makes any difference

Nope. Just means its heated with a proper earth