What's my shudder

My 156 2002 2.0 JTS has developed a shudder. Feels a bit like an automatic
changing gear - a misfire or perhaps fuel/air not getting through properly
or enough.

It happens when accelerating hard at lower (2000-3000 revs). 2 or 3 times,
the shudders also cause the computer to splutter the standard "Engine
control system failure - go to dealer". To avoid the shudder, I just back
off a little on the accellerator.

It is in for its 60k service next month - is that a spark plug change
service?

GT wrote:
> My 156 2002 2.0 JTS has developed a shudder. Feels a bit like an automatic
> changing gear - a misfire or perhaps fuel/air not getting through properly
> or enough.
>
> It happens when accelerating hard at lower (2000-3000 revs). 2 or 3 times,
> the shudders also cause the computer to splutter the standard "Engine
> control system failure - go to dealer". To avoid the shudder, I just back
> off a little on the accellerator.
>
> It is in for its 60k service next month - is that a spark plug change
> service?
>
>
Sounds like a misfire. IIRC the plugs are indeed changed.

--
Catman MIB#14 SKoGA#6 TEAR#4 BOTAFOF#38 Apostle#21 COSOC#3
Tyger, Tyger Burning Bright (Remove rust to reply)
116 Giulietta 3.0l Sprint 1.7 156 TS 145 2.0 Cloverleaf 156 V6 2.5 S2
Triumph Sprint ST 1050: It's blue, see.
www.cuore-sportivo.co.uk

On Mon, 24 Sep 2007 10:41:55 GMT, Catman
> wrote:

>GT wrote:
>> My 156 2002 2.0 JTS has developed a shudder. Feels a bit like an automatic
>> changing gear - a misfire or perhaps fuel/air not getting through properly
>> or enough.
>>
>> It happens when accelerating hard at lower (2000-3000 revs). 2 or 3 times,
>> the shudders also cause the computer to splutter the standard "Engine
>> control system failure - go to dealer". To avoid the shudder, I just back
>> off a little on the accellerator.
>>
>> It is in for its 60k service next month - is that a spark plug change
>> service?
>>
>>
>Sounds like a misfire. IIRC the plugs are indeed changed.

With that mileage and age, I'd wonder if the MAF (Mass Airflow Meter)
was gubbed.

--
Z
Scotland
Alfa Romeo 156 2.4JTD Veloce Leather
'Oil' be seeing you..
(Email without 'Alfa' in subject are auto-deleted..sorry!)

Zathras wrote:
> On Mon, 24 Sep 2007 10:41:55 GMT, Catman
> > wrote:
>
>> GT wrote:
>>> My 156 2002 2.0 JTS has developed a shudder. Feels a bit like an automatic
>>> changing gear - a misfire or perhaps fuel/air not getting through properly
>>> or enough.
>>>
>>> It happens when accelerating hard at lower (2000-3000 revs). 2 or 3 times,
>>> the shudders also cause the computer to splutter the standard "Engine
>>> control system failure - go to dealer". To avoid the shudder, I just back
>>> off a little on the accellerator.
>>>
>>> It is in for its 60k service next month - is that a spark plug change
>>> service?
>>>
>>>
>> Sounds like a misfire. IIRC the plugs are indeed changed.
>
> With that mileage and age, I'd wonder if the MAF (Mass Airflow Meter)
> was gubbed.
>

Certainly plausible, although I would be slightly surprised if it did
that IYSWIM. The other thing that just springs to mind is a failure of
the throttle sensor pot. Don't they get grubby? If it's same rev range,
same gear liklihood would be similar throttle position....

--
Catman MIB#14 SKoGA#6 TEAR#4 BOTAFOF#38 Apostle#21 COSOC#3
Tyger, Tyger Burning Bright (Remove rust to reply)
116 Giulietta 3.0l Sprint 1.7 156 TS 145 2.0 Cloverleaf 156 V6 2.5 S2
Triumph Sprint ST 1050: It's blue, see.
www.cuore-sportivo.co.uk

"Catman" > wrote in message
m...
> Zathras wrote:
>> On Mon, 24 Sep 2007 10:41:55 GMT, Catman
>> > wrote:
>>
>>> GT wrote:
>>>> My 156 2002 2.0 JTS has developed a shudder. Feels a bit like an
>>>> automatic changing gear - a misfire or perhaps fuel/air not getting
>>>> through properly or enough.
>>>>
>>>> It happens when accelerating hard at lower (2000-3000 revs). 2 or 3
>>>> times, the shudders also cause the computer to splutter the standard
>>>> "Engine control system failure - go to dealer". To avoid the shudder, I
>>>> just back off a little on the accellerator.
>>>>
>>>> It is in for its 60k service next month - is that a spark plug change
>>>> service?
>>>>
>>>>
>>> Sounds like a misfire. IIRC the plugs are indeed changed.
>>
>> With that mileage and age, I'd wonder if the MAF (Mass Airflow Meter)
>> was gubbed.
>>
>
> Certainly plausible, although I would be slightly surprised if it did that
> IYSWIM. The other thing that just springs to mind is a failure of the
> throttle sensor pot. Don't they get grubby? If it's same rev range, same
> gear liklihood would be similar throttle position....

Happens in 4th and 5th - not in that rev range for long in the other 3. It
seems to be around the same rev range. However on the family holiday to
France and back, I didn't tend to rev much higher than 4000 anyway, so can't
truely confirm that.

I thought it might be dirty fuel, but the problem has persisted for over a
month now and several fill-ups in 3 countries.

It feels like the engine either isn't getting enough air or enough fuel, or
the fuel just isn't burning properly - best description would be a cough,
before returning to normal.

I think it was a little worse when I filled up with 'normal' unleaded
instead of the 98 octane stuff, but I may have just imagined it!

Its not really a major problem and only happens now and again, when I am
really pushing it. It quickly splutters through the problem and then
accelerates OK again.

What level of detail is given when interrogating the computer for past error
messages? Will there be a record of which part caused the problem (on the 3
occasions when the computer complained).

"Catman" > wrote in message
m...
> GT wrote:
>> My 156 2002 2.0 JTS has developed a shudder. Feels a bit like an
>> automatic changing gear - a misfire or perhaps fuel/air not getting
>> through properly or enough.
>>
>> It happens when accelerating hard at lower (2000-3000 revs). 2 or 3
>> times, the shudders also cause the computer to splutter the standard
>> "Engine control system failure - go to dealer". To avoid the shudder, I
>> just back off a little on the accellerator.
>>
>> It is in for its 60k service next month - is that a spark plug change
>> service?
>>
>>
> Sounds like a misfire. IIRC the plugs are indeed changed.

Would a misfire get worse when the engine is hotter? This does!

Also I have noticed that the temperature gauge moves much more these days.
It used to warm up to 70 degrees, then hardly ever move practically
regardless of driving (motorway speed down to a queue used to cause it to
rise). Nowadays it warms up to nearer 80 degrees and fluctuates much more -
over 90 and down to about 75 degrees. Is this perhaps an age thing (4yr old
2.0 JTS) or could it be related to dying sparks?

GT wrote:
> "Catman" > wrote in message
> m...
>> GT wrote:
>>> My 156 2002 2.0 JTS has developed a shudder. Feels a bit like an
>>> automatic changing gear - a misfire or perhaps fuel/air not getting
>>> through properly or enough.
>>>
>>> It happens when accelerating hard at lower (2000-3000 revs). 2 or 3
>>> times, the shudders also cause the computer to splutter the standard
>>> "Engine control system failure - go to dealer". To avoid the shudder, I
>>> just back off a little on the accellerator.
>>>
>>> It is in for its 60k service next month - is that a spark plug change
>>> service?
>>>
>>>
>> Sounds like a misfire. IIRC the plugs are indeed changed.
>
> Would a misfire get worse when the engine is hotter? This does!

Could do, if it's running lean, that may make the engine hotter. Cause
and effect are swapped.

C
>
> Also I have noticed that the temperature gauge moves much more these days.
> It used to warm up to 70 degrees, then hardly ever move practically
> regardless of driving (motorway speed down to a queue used to cause it to
> rise). Nowadays it warms up to nearer 80 degrees and fluctuates much more -
> over 90 and down to about 75 degrees. Is this perhaps an age thing (4yr old
> 2.0 JTS) or could it be related to dying sparks?
>
>


--
Catman MIB#14 SKoGA#6 TEAR#4 BOTAFOF#38 Apostle#21 COSOC#3
Tyger, Tyger Burning Bright (Remove rust to reply)
116 Giulietta 3.0l Sprint 1.7 156 TS 145 2.0 Cloverleaf 156 V6 2.5 S2
Triumph Sprint ST 1050: It's blue, see.
www.cuore-sportivo.co.uk

"Catman" > wrote in message
.. .
> GT wrote:
>> "Catman" > wrote in message
>> m...
>>> GT wrote:
>>>> My 156 2002 2.0 JTS has developed a shudder. Feels a bit like an
>>>> automatic changing gear - a misfire or perhaps fuel/air not getting
>>>> through properly or enough.
>>>>
>>>> It happens when accelerating hard at lower (2000-3000 revs). 2 or 3
>>>> times, the shudders also cause the computer to splutter the standard
>>>> "Engine control system failure - go to dealer". To avoid the shudder, I
>>>> just back off a little on the accellerator.
>>>>
>>>> It is in for its 60k service next month - is that a spark plug change
>>>> service?
>>>>
>>>>
>>> Sounds like a misfire. IIRC the plugs are indeed changed.
>>
>> Would a misfire get worse when the engine is hotter? This does!
>
> Could do, if it's running lean, that may make the engine hotter. Cause and
> effect are swapped.

Drive through to work this morning and it didn't shudder once and the
temperature barely rose above 70, whilst my speed rarely fell bellow!