2.0 JTS problems - Alfa Romeo Forum
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(Post Link) post #1 of 5 Old 20-08-12 Thread Starter
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Help 2.0 JTS problems


I've got myself a 2005 156, 2.0 JTS with around 100k km on the clock which I have a couple of problems with.

1. The engine's uneven. It's mostly noticeable on idle, where it jerks some, but, usually isn't VERY noticeable, unless you stand behind her and listen to the exhaust. It's pretty noticeable there...
2. It consumes way too much. It's not that much of a problem for me, as I don't drive a lot, but it seems to be a symptom. 10l/100km of mostly highway driving and 14l+/100km of very short (2-4km, but basically without any stops) daily communes.
3. The thing that seems suspicious to me in the ecuscan is Air Flow graph, which shows something around 24kg/h+ at idle. From what I've heard it's way too much, but, perhaps, someone could correct me. I would also be grateful for any clues on what else should I look at on ECUScan.
3a. For what it's worth, the lambda graphs seem to go together in pairs, at idle running around 2.4v and 0.030v respectively.

4. Sometimes (quite rarely and usually when it's pretty cold/damp), the MCSF lamp starts blinking and blinks for a minute or two, until I rev the car a bit. It, then, leaves some mis-firing on 3-rd cylinder errors on the ecuscan.
5. Sometimes, quite rarely, pre-cat lambda 2 goes out, but then (after erasing the error, resetting the self-adaptation and sometimes some plugging it back and forth) the error goes off and would not reappear for quite a long time.

If someone could make something of all this data, or, at least request some more data, I would be extremely grateful

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The idling / misfire is probably the coilpack on no. 3 cylinder.

The consumption / air flow may be related to the MAF, try spraying some electrical contact cleaner on it and possibly cleaning VERY gently with cotton buds.

The Lambda error is 99% likely to be a faulty wiring connector - a well known issue with the JTS engine. Some folks chop the connectors off and solder the wires, or use new connectors. You'll probably find that although you get the Motor Control System Failure alert, and the engine light come on, the car still runs fine. Just clear the code if it bugs you.

Looking at all the faults as a whole, some people have reportedly cured similar snags by cleaning the connectors in the large wiring connector on the bulkhead.

Hope this helps.
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(Post Link) post #3 of 5 Old 22-08-12 Thread Starter
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Thanks, will try and see!
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GT Jtdm with Q2

I had error codes suggesting the 3rd coilpack. When I took it in for a service I was told that it could just be the spark plug on it's way out. Mine were due fairly soon and since changing them I haven't had the MCSF come on again. Just a thought...
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156 2.0 JTS

Mine was a problem in the wiring loom, but I only found that out after replacing plugs, coil pack, and my nerves
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airflow , consumption , jts , mcsf , problems

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