V6 engine problem

The V6 has developed something of a problem. It; a bit odd really:

If I do something like fluff a gear change, and let the engine revs drop
too low, the engine management light comes on and the throttle respsonse
goes rather odd.
If you take your foot off the throttle and then put it back on (as in a
gear change) there is a very distinct lag (maybe a second plus) before
anything happens. It makes no difference where in the rev range you are,
or how fast you re-apply throttle. The power comes on without apparent
loss, it;s just 'late'. If you keep constant throttle you can hear the
engine pick up after the delay.

Shutting off and starting again always clears it (takes maybe a minute
for the light to go off) but the lag vanishes immediately.

Suggestions from the house?
--
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:

> The V6 has developed something of a problem. It; a bit odd really:
>
> If I do something like fluff a gear change, and let the engine revs drop
> too low, the engine management light comes on and the throttle respsonse
> goes rather odd.
> If you take your foot off the throttle and then put it back on (as in a
> gear change) there is a very distinct lag (maybe a second plus) before
> anything happens. It makes no difference where in the rev range you are,
> or how fast you re-apply throttle. The power comes on without apparent
> loss, it;s just 'late'. If you keep constant throttle you can hear the
> engine pick up after the delay.
>
> Shutting off and starting again always clears it (takes maybe a minute
> for the light to go off) but the lag vanishes immediately.
>
> Suggestions from the house?

It's ****ed. I'll take it off your hands without charge to save you the
hassle of scrapping it.
--
SteveH 'You're not a real petrolhead unless you've owned an Alfa Romeo'
www.italiancar.co.uk - Honda VFR800 - Hongdou GY200 - Alfa 75 TSpark
Alfa 156 TSpark - B6 Passat 2.0TDI SE - COSOC KOTL
BOTAFOT #87 - BOTAFOF #18 - MRO # - UKRMSBC #7 - Apostle #2 - YTC #

SteveH wrote:
> Catman > wrote:
>
>> The V6 has developed something of a problem. It; a bit odd really:
>>
>> If I do something like fluff a gear change, and let the engine revs drop
>> too low, the engine management light comes on and the throttle respsonse
>> goes rather odd.
>> If you take your foot off the throttle and then put it back on (as in a
>> gear change) there is a very distinct lag (maybe a second plus) before
>> anything happens. It makes no difference where in the rev range you are,
>> or how fast you re-apply throttle. The power comes on without apparent
>> loss, it;s just 'late'. If you keep constant throttle you can hear the
>> engine pick up after the delay.
>>
>> Shutting off and starting again always clears it (takes maybe a minute
>> for the light to go off) but the lag vanishes immediately.
>>
>> Suggestions from the house?
>
> It's ****ed. I'll take it off your hands without charge to save you the
> hassle of scrapping it.

Perm 2 from 4
1) Angle grinder
2) It's ****ed, I'll take it off your hands for a fiver *
3) **** in the tank
4) ginge

--
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 Fri, 23 Nov 2007 20:37:30 GMT, Catman
> wrote:

>The V6 has developed something of a problem.

Which one?

>Suggestions from the house?

<guess>

ecu getting daft inputs from..

O2 sensor
Throttle position sensor

</guess>

I'm just guessing though!

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

Zathras wrote:
> On Fri, 23 Nov 2007 20:37:30 GMT, Catman
> > wrote:
>
>> The V6 has developed something of a problem.
>
> Which one?

Oh, ah yes, I actually forgot I owned two.... The 24 valve job.
>
>> Suggestions from the house?
>
> <guess>
>
> ecu getting daft inputs from..
>
> O2 sensor
> Throttle position sensor
>
> </guess>
>
> I'm just guessing though!
>

Similar to my guesses....
Think is I can't figure out why if the sensor was duff the problem would
go away after restart.


--
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 Sat, 24 Nov 2007 14:46:40 GMT, Catman
> wrote:

>Think is I can't figure out why if the sensor was duff the problem would
>go away after restart.

The ecu may be resetting or it could (ho ho!) be a intermittent
connection to a sensor..more guesses though.

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

Zathras wrote:
> On Sat, 24 Nov 2007 14:46:40 GMT, Catman
> > wrote:
>
>> Think is I can't figure out why if the sensor was duff the problem would
>> go away after restart.
>
> The ecu may be resetting or it could (ho ho!) be a intermittent
> connection to a sensor..more guesses though.
>
Yeah. Needs a reader really. I'm kind of thinking there is some kind of
transient fault, which is toggling a 'limp home' type thing.

--
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 Sat, 24 Nov 2007 18:49:35 +0000, Catman blather'd thus:

> Zathras wrote:
>> On Sat, 24 Nov 2007 14:46:40 GMT, Catman
>> > wrote:
>>
>>> Think is I can't figure out why if the sensor was duff the problem
>>> would go away after restart.
>>
>> The ecu may be resetting or it could (ho ho!) be a intermittent
>> connection to a sensor..more guesses though.
>>
> Yeah. Needs a reader really. I'm kind of thinking there is some kind of
> transient fault, which is toggling a 'limp home' type thing.

You might check the TPS with an ohm meter (a REAL one: analog) before you
have it connected to The MotherShip. The TPS could be passing voltage in
the "0" (or "start") position thus on restart the ECU gets proper
signal... at SOME point in the travel it may have a discontinuity.

My knowing BIG words should impress ya, huh?



--
Dr E--
mhm 17x1
SGM #3
smeeter #13
FWAC:"Old No.-7"
Surgeon General-Relativity
Commodore/Upper-Half/1st Virginia Volunteers/CEsium Brigade
NF & TCIB. ATFFFIQ
------------------------------------------------------------------------------
"The flames kindled on the fourth of July, seventeen hundred and
seventy six, have spread over too much of the globe to be extinguished
by the feeble engines of despotism." -- Thomas Jefferson

Dr Entropy wrote:
> On Sat, 24 Nov 2007 18:49:35 +0000, Catman blather'd thus:
>
>> Zathras wrote:
>>> On Sat, 24 Nov 2007 14:46:40 GMT, Catman
>>> > wrote:
>>>
>>>> Think is I can't figure out why if the sensor was duff the problem
>>>> would go away after restart.
>>> The ecu may be resetting or it could (ho ho!) be a intermittent
>>> connection to a sensor..more guesses though.
>>>
>> Yeah. Needs a reader really. I'm kind of thinking there is some kind of
>> transient fault, which is toggling a 'limp home' type thing.
>
> You might check the TPS with an ohm meter (a REAL one: analog) before you
> have it connected to The MotherShip. The TPS could be passing voltage in
> the "0" (or "start") position thus on restart the ECU gets proper
> signal... at SOME point in the travel it may have a discontinuity.

Interesting thought. I would have thought that it would die every time
it passed that point though?
>
> My knowing BIG words should impress ya, huh?

Shocks would be closer

It did it again today, but this time I was tooling along at constant
throttle. Hit some kind of bump and it went. Beginning to smell like a
dodgy connection forcing it into some kind of limp hope mode to me.


--
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 Sun, 25 Nov 2007 16:39:19 +0000, Catman blather'd thus:

> Dr Entropy wrote:
>> On Sat, 24 Nov 2007 18:49:35 +0000, Catman blather'd thus:
>>
>>> Zathras wrote:
>>>> On Sat, 24 Nov 2007 14:46:40 GMT, Catman
>>>> > wrote:
>>>>
>>>>> Think is I can't figure out why if the sensor was duff the problem
>>>>> would go away after restart.
>>>> The ecu may be resetting or it could (ho ho!) be a intermittent
>>>> connection to a sensor..more guesses though.
>>>>
>>> Yeah. Needs a reader really. I'm kind of thinking there is some kind
>>> of transient fault, which is toggling a 'limp home' type thing.
>>
>> You might check the TPS with an ohm meter (a REAL one: analog) before
>> you have it connected to The MotherShip. The TPS could be passing
>> voltage in the "0" (or "start") position thus on restart the ECU gets
>> proper signal... at SOME point in the travel it may have a
>> discontinuity.
>
> Interesting thought. I would have thought that it would die every time
> it passed that point though?
>>
>> My knowing BIG words should impress ya, huh?
>
> Shocks would be closer

....i wuz tryin' t' be understating... Practicin' me "English". :smirk:
>
> It did it again today, but this time I was tooling along at constant
> throttle. Hit some kind of bump and it went. Beginning to smell like a
> dodgy connection forcing it into some kind of limp hope mode to me.


hmm. Have you checked all those fancy/funny 'lectronic connectors in
there yet? A good "wiggle test" could turn up something. It'll likely be
somfin' stoopid, y'know. Are they the Bosch ones? I've seen 'em with ropy
connection sometimes, even shiny-new.


--
Dr E--
mhm 17x1
SGM #3
smeeter #13
FWAC:"Old No.-7"
Surgeon General-Relativity
Commodore/Upper-Half/1st Virginia Volunteers/CEsium Brigade
NF & TCIB. ATFFFIQ
------------------------------------------------------------------------------
"The flames kindled on the fourth of July, seventeen hundred and
seventy six, have spread over too much of the globe to be extinguished
by the feeble engines of despotism." -- Thomas Jefferson