Author Topic: Alfa 159 JTD 2.4 Diesel Engine Problems!!!  (Read 24186 times)

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Alfa 159 JTD 2.4 Diesel Engine Problems!!!
« on: December 08, 2011, 06:40:21 PM »
 Hi Everyone,

 I have a 159 JTD 2.4 Diesel which is really driving me crazy! The problem is the engine runs roughly, paricularly under acceleration and appears to get better if I accelerate hard. At the same time the tacho seems to dip up and down when the engine goes wrong. I have taken my poor car to the dealer who has already changed the thermostat and related sensors and charged me $850! The problem is still there. Now they have sent all the injectors to be cleaned and they are saying that maybe I need a new injector? The car has only travelled 65000km and I don't drive it very hard! Can someone out there please help me as I don't think the dealer knows what he is doing?

Thank you


Evan Bottcher

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Re: Alfa 159 JTD 2.4 Diesel Engine Problems!!!
« Reply #1 on: December 08, 2011, 07:29:12 PM »
The most common problem with the diesel seems to be blockage of the EGR valve (exhaust gas recirculation).  On our car this has caused rough idle, and generally poor acceleration and fuel economy.  At idle the tacho shows the engine stumbling gently for a bit, then clearing.  Theory is that it's worse in Australia than elsewhere due to poor fuel quality compared to Europe.  We've had this twice in 15,000km the first time accompanied by an engine-fault message, the second time recently without any message.  Both times it's required removal and cleaning of the valve, which is not a huge job.

The other common problem is the DPF (particulate filter) in the exhaust clogging, especially if you drive short distances.  The DPF needs to 'regen' basically by closing a solenoid valve and running a very rich mixture, until all the soot in the filter burns away.  If you don't drive a decent distance at a fairly constant speed, it can't regen.  I think if the DPF cannot regen you get a specific message on the dash.

However - these are really common faults with the 2.4 JTDm, and I'd expect a genuine Alfa dealer to identify those problems immediately - so it's quite possibly something else.

Which state are you in?
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Re: Alfa 159 JTD 2.4 Diesel Engine Problems!!!
« Reply #2 on: December 08, 2011, 08:08:28 PM »

I've a 1.9JTD.

It could be anything from a coked EGR or DPF as Evan says to a split boost hose, dodgy sensor or a crap battery (yes, happened to me)

First step... What error codes does their examiner display.. they have pulled the error codes from the ECU yes ?
These codes will isolate which sensors are faulting or reading out of spec which will help diagnose the correct problem
If they haven't (or can't) then they're just replacing things willy, nilly - which is just going to get expensive for you.

'66 Duetto (lacework of doom)
'73 1600 GT Junior (ensconced)
'03 156 1.9JTD Sportwagon (daily driver)


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Re: Alfa 159 JTD 2.4 Diesel Engine Problems!!!
« Reply #3 on: December 08, 2011, 09:39:54 PM »
 Thank you for your answers so far. Unfortunately it is not the EGR valve, firstly had it cleaned under warranty, then replaced for several hundred dollars at about 60.000km. The dealer has all the right equipment but none of the answers! I guess I will just have to keep paying out money for them to experiment. Just how good are these cars? I am really sad, such a nice looking car but I can't find a dealer who knows what they are doing! To have so many expensive things go wrong at such low km is very sad.



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Re: Alfa 159 JTD 2.4 Diesel Engine Problems!!!
« Reply #4 on: December 18, 2011, 10:56:00 AM »
Check that the duct from the air flow meter to the turbo inlet is tight at the inlet to the turbo. The crimped hose clip is often loose. Replace it with a screwed clamp. Fixed all the rough running on mine immediately.