Could this be a lambda issue?
07-14-2009 | 06:16 AM
#1
Guest
Posts: n/a
Could this be a lambda issue?
1993 Audi 80 2.0 single point (ABT engine).
It's my dad's car, had it from new & been well serviced over the years. I'm
trying to diagnose poor top end performance and thinking it may be the
lambda sensor, or any other suggestions welcome.
Starts & drives well but gutless at top end. Up to about half throttle it
has plenty of pull but put your foot down for overtake or approaching
inclines and there isn't much there and takes a long time to build up
speed - usually have to knock it down the gears. Feels as though it wants
to go but a lack of fuelling at top end is holding it back. In fact if your
cruising along say at half throttle and plant your foot down it feels like
it actually slows down before very slowly starts to build up speed. TPS &
various other sensors appear ok (within Autodata spec) & checked for any
vacuum, air leaks. The injector unit to manifold rubber flange looked a bit
worn & cracked but I've replaced that.
Only thing I can think of is the lambda sensor as the cars done about 120k
miles on the original so was wondering if that could be on its way out and
slow at sending the correct signal to increase fuelling at top end?
It's my dad's car, had it from new & been well serviced over the years. I'm
trying to diagnose poor top end performance and thinking it may be the
lambda sensor, or any other suggestions welcome.
Starts & drives well but gutless at top end. Up to about half throttle it
has plenty of pull but put your foot down for overtake or approaching
inclines and there isn't much there and takes a long time to build up
speed - usually have to knock it down the gears. Feels as though it wants
to go but a lack of fuelling at top end is holding it back. In fact if your
cruising along say at half throttle and plant your foot down it feels like
it actually slows down before very slowly starts to build up speed. TPS &
various other sensors appear ok (within Autodata spec) & checked for any
vacuum, air leaks. The injector unit to manifold rubber flange looked a bit
worn & cracked but I've replaced that.
Only thing I can think of is the lambda sensor as the cars done about 120k
miles on the original so was wondering if that could be on its way out and
slow at sending the correct signal to increase fuelling at top end?
07-14-2009 | 06:22 AM
#2
Guest
Posts: n/a
Re: Could this be a lambda issue?
Redwood wrote:
> 1993 Audi 80 2.0 single point (ABT engine).
>
> It's my dad's car, had it from new & been well serviced over the
> years. I'm trying to diagnose poor top end performance and thinking
> it may be the lambda sensor, or any other suggestions welcome.
>
> Starts & drives well but gutless at top end. Up to about half
> throttle it has plenty of pull but put your foot down for overtake or
> approaching inclines and there isn't much there and takes a long time
> to build up speed - usually have to knock it down the gears. Feels as
> though it
> wants to go but a lack of fuelling at top end is holding it back. In
> fact if your cruising along say at half throttle and plant your foot
> down it feels like it actually slows down before very slowly starts
> to build up speed. TPS & various other sensors appear ok (within
> Autodata spec) & checked for any vacuum, air leaks. The injector
> unit to manifold rubber flange looked a bit worn & cracked but I've
> replaced that.
> Only thing I can think of is the lambda sensor as the cars done about
> 120k miles on the original so was wondering if that could be on its
> way out and slow at sending the correct signal to increase fuelling
> at top end?
blocked cat would be my first thought
> 1993 Audi 80 2.0 single point (ABT engine).
>
> It's my dad's car, had it from new & been well serviced over the
> years. I'm trying to diagnose poor top end performance and thinking
> it may be the lambda sensor, or any other suggestions welcome.
>
> Starts & drives well but gutless at top end. Up to about half
> throttle it has plenty of pull but put your foot down for overtake or
> approaching inclines and there isn't much there and takes a long time
> to build up speed - usually have to knock it down the gears. Feels as
> though it
> wants to go but a lack of fuelling at top end is holding it back. In
> fact if your cruising along say at half throttle and plant your foot
> down it feels like it actually slows down before very slowly starts
> to build up speed. TPS & various other sensors appear ok (within
> Autodata spec) & checked for any vacuum, air leaks. The injector
> unit to manifold rubber flange looked a bit worn & cracked but I've
> replaced that.
> Only thing I can think of is the lambda sensor as the cars done about
> 120k miles on the original so was wondering if that could be on its
> way out and slow at sending the correct signal to increase fuelling
> at top end?
blocked cat would be my first thought
07-14-2009 | 06:24 AM
#3
Guest
Posts: n/a
Re: Could this be a lambda issue?
In article <7c347tF255srkU1@mid.individual.net>,
Redwood <not@home.net> wrote:
> Starts & drives well but gutless at top end. Up to about half throttle
> it has plenty of pull but put your foot down for overtake or
> approaching inclines and there isn't much there and takes a long time
> to build up speed - usually have to knock it down the gears.
On full throttle most cars go open loop so the lambda sensor no longer
controls the mixture.
--
*The problem with the gene pool is that there is no lifeguard *
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
Redwood <not@home.net> wrote:
> Starts & drives well but gutless at top end. Up to about half throttle
> it has plenty of pull but put your foot down for overtake or
> approaching inclines and there isn't much there and takes a long time
> to build up speed - usually have to knock it down the gears.
On full throttle most cars go open loop so the lambda sensor no longer
controls the mixture.
--
*The problem with the gene pool is that there is no lifeguard *
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
07-14-2009 | 07:01 AM
#4
Guest
Posts: n/a
Re: Could this be a lambda issue?
"Mrcheerful" <nbkm57@hotmail.com> wrote in message
news
%Y6m.56114$OO7.51714@text.news.virginmedia.c om...
> Redwood wrote:
>> 1993 Audi 80 2.0 single point (ABT engine).
>>
>> It's my dad's car, had it from new & been well serviced over the
>> years. I'm trying to diagnose poor top end performance and thinking
>> it may be the lambda sensor, or any other suggestions welcome.
>>
>> Starts & drives well but gutless at top end. Up to about half
>> throttle it has plenty of pull but put your foot down for overtake or
>> approaching inclines and there isn't much there and takes a long time
>> to build up speed - usually have to knock it down the gears. Feels as
>> though it
>> wants to go but a lack of fuelling at top end is holding it back. In
>> fact if your cruising along say at half throttle and plant your foot
>> down it feels like it actually slows down before very slowly starts
>> to build up speed. TPS & various other sensors appear ok (within
>> Autodata spec) & checked for any vacuum, air leaks. The injector
>> unit to manifold rubber flange looked a bit worn & cracked but I've
>> replaced that.
>> Only thing I can think of is the lambda sensor as the cars done about
>> 120k miles on the original so was wondering if that could be on its
>> way out and slow at sending the correct signal to increase fuelling
>> at top end?
>
> blocked cat would be my first thought
It did have a new cat I think about 2 year ago. If I remember it snapped at
the joint where it connects to the exhaust so had to replace the whole cat
section, although I suppose even a newish cat can break up. It goes for an
MoT later this month so will get the garage have a good poke about see if
they can see anything. Not sure if this is also relevant but it idles ok
with no lumpiness but I notice that if you try and hold the revs at a steady
fast idle it fluctuates up & down slightly.
news
%Y6m.56114$OO7.51714@text.news.virginmedia.c om...> Redwood wrote:
>> 1993 Audi 80 2.0 single point (ABT engine).
>>
>> It's my dad's car, had it from new & been well serviced over the
>> years. I'm trying to diagnose poor top end performance and thinking
>> it may be the lambda sensor, or any other suggestions welcome.
>>
>> Starts & drives well but gutless at top end. Up to about half
>> throttle it has plenty of pull but put your foot down for overtake or
>> approaching inclines and there isn't much there and takes a long time
>> to build up speed - usually have to knock it down the gears. Feels as
>> though it
>> wants to go but a lack of fuelling at top end is holding it back. In
>> fact if your cruising along say at half throttle and plant your foot
>> down it feels like it actually slows down before very slowly starts
>> to build up speed. TPS & various other sensors appear ok (within
>> Autodata spec) & checked for any vacuum, air leaks. The injector
>> unit to manifold rubber flange looked a bit worn & cracked but I've
>> replaced that.
>> Only thing I can think of is the lambda sensor as the cars done about
>> 120k miles on the original so was wondering if that could be on its
>> way out and slow at sending the correct signal to increase fuelling
>> at top end?
>
> blocked cat would be my first thought
It did have a new cat I think about 2 year ago. If I remember it snapped at
the joint where it connects to the exhaust so had to replace the whole cat
section, although I suppose even a newish cat can break up. It goes for an
MoT later this month so will get the garage have a good poke about see if
they can see anything. Not sure if this is also relevant but it idles ok
with no lumpiness but I notice that if you try and hold the revs at a steady
fast idle it fluctuates up & down slightly.
07-14-2009 | 07:16 AM
#5
Guest
Posts: n/a
Re: Could this be a lambda issue?
Redwood wrote:
> 1993 Audi 80 2.0 single point (ABT engine).
>
> It's my dad's car, had it from new & been well serviced over the years. I'm
> trying to diagnose poor top end performance and thinking it may be the
> lambda sensor, or any other suggestions welcome.
>
> Starts & drives well but gutless at top end. Up to about half throttle it
> has plenty of pull but put your foot down for overtake or approaching
> inclines and there isn't much there and takes a long time to build up
> speed - usually have to knock it down the gears. Feels as though it wants
> to go but a lack of fuelling at top end is holding it back. In fact if your
> cruising along say at half throttle and plant your foot down it feels like
> it actually slows down before very slowly starts to build up speed. TPS &
> various other sensors appear ok (within Autodata spec) & checked for any
> vacuum, air leaks. The injector unit to manifold rubber flange looked a bit
> worn & cracked but I've replaced that.
>
> Only thing I can think of is the lambda sensor as the cars done about 120k
> miles on the original so was wondering if that could be on its way out and
> slow at sending the correct signal to increase fuelling at top end?
>
>
Has it got an air flow meter? Is it stuck?
> 1993 Audi 80 2.0 single point (ABT engine).
>
> It's my dad's car, had it from new & been well serviced over the years. I'm
> trying to diagnose poor top end performance and thinking it may be the
> lambda sensor, or any other suggestions welcome.
>
> Starts & drives well but gutless at top end. Up to about half throttle it
> has plenty of pull but put your foot down for overtake or approaching
> inclines and there isn't much there and takes a long time to build up
> speed - usually have to knock it down the gears. Feels as though it wants
> to go but a lack of fuelling at top end is holding it back. In fact if your
> cruising along say at half throttle and plant your foot down it feels like
> it actually slows down before very slowly starts to build up speed. TPS &
> various other sensors appear ok (within Autodata spec) & checked for any
> vacuum, air leaks. The injector unit to manifold rubber flange looked a bit
> worn & cracked but I've replaced that.
>
> Only thing I can think of is the lambda sensor as the cars done about 120k
> miles on the original so was wondering if that could be on its way out and
> slow at sending the correct signal to increase fuelling at top end?
>
>
Has it got an air flow meter? Is it stuck?
07-14-2009 | 07:22 AM
#6
Guest
Posts: n/a
Re: Could this be a lambda issue?
"Dave Plowman (News)" <dave@davenoise.co.uk> wrote in message
news:507aada9a2dave@davenoise.co.uk...
> In article <7c347tF255srkU1@mid.individual.net>,
> Redwood <not@home.net> wrote:
>> Starts & drives well but gutless at top end. Up to about half throttle
>> it has plenty of pull but put your foot down for overtake or
>> approaching inclines and there isn't much there and takes a long time
>> to build up speed - usually have to knock it down the gears.
>
> On full throttle most cars go open loop so the lambda sensor no longer
> controls the mixture.
I guess that would rule out the lambda then. It does seem fuel related
though and if you ease off the throttle you can feel it become more
responsive.
news:507aada9a2dave@davenoise.co.uk...
> In article <7c347tF255srkU1@mid.individual.net>,
> Redwood <not@home.net> wrote:
>> Starts & drives well but gutless at top end. Up to about half throttle
>> it has plenty of pull but put your foot down for overtake or
>> approaching inclines and there isn't much there and takes a long time
>> to build up speed - usually have to knock it down the gears.
>
> On full throttle most cars go open loop so the lambda sensor no longer
> controls the mixture.
I guess that would rule out the lambda then. It does seem fuel related
though and if you ease off the throttle you can feel it become more
responsive.
07-14-2009 | 07:58 AM
#7
Guest
Posts: n/a
Re: Could this be a lambda issue?
Hmmm
Is there a full/wide open throttle switch on it? What sensors are on the
throttle body since I am thinking two.
I suspect that after you ruled out the cat.
If the full/wide open throttle switch is not functioning then maybe the 02
sensor is not cutting out and allowing full power.
Again I am not familiar with the '93 Audi 80's there.
Of course I ASSuME that you check for any obstructions in the air intake
system. I have seen nests inside of air cleaner boxes along with leaves
restricting air flow.
JMHO
--
later,
(One out of many daves)
"Redwood" <not@home.net> wrote in message
news:7c3850F25tv3dU1@mid.individual.net...
> "Dave Plowman (News)" <dave@davenoise.co.uk> wrote in message
> news:507aada9a2dave@davenoise.co.uk...
>> In article <7c347tF255srkU1@mid.individual.net>,
>> Redwood <not@home.net> wrote:
>>> Starts & drives well but gutless at top end. Up to about half throttle
>>> it has plenty of pull but put your foot down for overtake or
>>> approaching inclines and there isn't much there and takes a long time
>>> to build up speed - usually have to knock it down the gears.
>>
>> On full throttle most cars go open loop so the lambda sensor no longer
>> controls the mixture.
>
> I guess that would rule out the lambda then. It does seem fuel related
> though and if you ease off the throttle you can feel it become more
> responsive.
>
Is there a full/wide open throttle switch on it? What sensors are on the
throttle body since I am thinking two.
I suspect that after you ruled out the cat.
If the full/wide open throttle switch is not functioning then maybe the 02
sensor is not cutting out and allowing full power.
Again I am not familiar with the '93 Audi 80's there.
Of course I ASSuME that you check for any obstructions in the air intake
system. I have seen nests inside of air cleaner boxes along with leaves
restricting air flow.
JMHO
--
later,
(One out of many daves)
"Redwood" <not@home.net> wrote in message
news:7c3850F25tv3dU1@mid.individual.net...
> "Dave Plowman (News)" <dave@davenoise.co.uk> wrote in message
> news:507aada9a2dave@davenoise.co.uk...
>> In article <7c347tF255srkU1@mid.individual.net>,
>> Redwood <not@home.net> wrote:
>>> Starts & drives well but gutless at top end. Up to about half throttle
>>> it has plenty of pull but put your foot down for overtake or
>>> approaching inclines and there isn't much there and takes a long time
>>> to build up speed - usually have to knock it down the gears.
>>
>> On full throttle most cars go open loop so the lambda sensor no longer
>> controls the mixture.
>
> I guess that would rule out the lambda then. It does seem fuel related
> though and if you ease off the throttle you can feel it become more
> responsive.
>
07-14-2009 | 08:21 AM
#8
Guest
Posts: n/a
Re: Could this be a lambda issue?
On Tue, 14 Jul 2009 11:16:15 +0100, Redwood <not@home.net> wrote:
> 1993 Audi 80 2.0 single point (ABT engine).
>
> It's my dad's car, had it from new & been well serviced over the years.
> I'm
> trying to diagnose poor top end performance and thinking it may be the
> lambda sensor, or any other suggestions welcome.
>
> Starts & drives well but gutless at top end. Up to about half throttle
> it
> has plenty of pull but put your foot down for overtake or approaching
> inclines and there isn't much there and takes a long time to build up
> speed - usually have to knock it down the gears. Feels as though it
> wants
> to go but a lack of fuelling at top end is holding it back. In fact if
> your
> cruising along say at half throttle and plant your foot down it feels
> like
> it actually slows down before very slowly starts to build up speed. TPS
> &
> various other sensors appear ok (within Autodata spec) & checked for any
> vacuum, air leaks. The injector unit to manifold rubber flange looked a
> bit
> worn & cracked but I've replaced that.
>
> Only thing I can think of is the lambda sensor as the cars done about
> 120k
> miles on the original so was wondering if that could be on its way out
> and
> slow at sending the correct signal to increase fuelling at top end?
>
>
How old's the fuel & air filter?
> 1993 Audi 80 2.0 single point (ABT engine).
>
> It's my dad's car, had it from new & been well serviced over the years.
> I'm
> trying to diagnose poor top end performance and thinking it may be the
> lambda sensor, or any other suggestions welcome.
>
> Starts & drives well but gutless at top end. Up to about half throttle
> it
> has plenty of pull but put your foot down for overtake or approaching
> inclines and there isn't much there and takes a long time to build up
> speed - usually have to knock it down the gears. Feels as though it
> wants
> to go but a lack of fuelling at top end is holding it back. In fact if
> your
> cruising along say at half throttle and plant your foot down it feels
> like
> it actually slows down before very slowly starts to build up speed. TPS
> &
> various other sensors appear ok (within Autodata spec) & checked for any
> vacuum, air leaks. The injector unit to manifold rubber flange looked a
> bit
> worn & cracked but I've replaced that.
>
> Only thing I can think of is the lambda sensor as the cars done about
> 120k
> miles on the original so was wondering if that could be on its way out
> and
> slow at sending the correct signal to increase fuelling at top end?
>
>
How old's the fuel & air filter?
07-14-2009 | 01:07 PM
#9
Guest
Posts: n/a
Re: Could this be a lambda issue?
In article <7c3850F25tv3dU1@mid.individual.net>, Redwood says...
> I guess that would rule out the lambda then. It does seem fuel related
> though and if you ease off the throttle you can feel it become more
> responsive.
Worn fuel pump giving low pressure at WOT?
Does it get an italian tuneup every so often?
--
Conor
www.notebooks-r-us.co.uk
I only please one person per day. Today is not your day. Tomorrow isn't
looking good either. - Scott Adams
> I guess that would rule out the lambda then. It does seem fuel related
> though and if you ease off the throttle you can feel it become more
> responsive.
Worn fuel pump giving low pressure at WOT?
Does it get an italian tuneup every so often?
--
Conor
www.notebooks-r-us.co.uk
I only please one person per day. Today is not your day. Tomorrow isn't
looking good either. - Scott Adams
07-15-2009 | 03:21 AM
#10
Guest
Posts: n/a
Re: Could this be a lambda issue?
Blah wrote:
> Redwood wrote:
>> 1993 Audi 80 2.0 single point (ABT engine).
>>
>> It's my dad's car, had it from new & been well serviced over the
>> years. I'm trying to diagnose poor top end performance and thinking it
>> may be the lambda sensor, or any other suggestions welcome.
>>
>> Starts & drives well but gutless at top end. Up to about half
>> throttle it has plenty of pull but put your foot down for overtake or
>> approaching inclines and there isn't much there and takes a long time
>> to build up speed - usually have to knock it down the gears. Feels as
>> though it wants to go but a lack of fuelling at top end is holding it
>> back. In fact if your cruising along say at half throttle and plant
>> your foot down it feels like it actually slows down before very slowly
>> starts to build up speed. TPS & various other sensors appear ok
>> (within Autodata spec) & checked for any vacuum, air leaks. The
>> injector unit to manifold rubber flange looked a bit worn & cracked
>> but I've replaced that.
>>
>> Only thing I can think of is the lambda sensor as the cars done about
>> 120k miles on the original so was wondering if that could be on its
>> way out and slow at sending the correct signal to increase fuelling at
>> top end?
>>
> Has it got an air flow meter? Is it stuck?
That was my thought- maybe a MAP sensor of a MAF or whatever it uses to
measure airflow in. I'm not familiar with the setup on this engine though.
> Redwood wrote:
>> 1993 Audi 80 2.0 single point (ABT engine).
>>
>> It's my dad's car, had it from new & been well serviced over the
>> years. I'm trying to diagnose poor top end performance and thinking it
>> may be the lambda sensor, or any other suggestions welcome.
>>
>> Starts & drives well but gutless at top end. Up to about half
>> throttle it has plenty of pull but put your foot down for overtake or
>> approaching inclines and there isn't much there and takes a long time
>> to build up speed - usually have to knock it down the gears. Feels as
>> though it wants to go but a lack of fuelling at top end is holding it
>> back. In fact if your cruising along say at half throttle and plant
>> your foot down it feels like it actually slows down before very slowly
>> starts to build up speed. TPS & various other sensors appear ok
>> (within Autodata spec) & checked for any vacuum, air leaks. The
>> injector unit to manifold rubber flange looked a bit worn & cracked
>> but I've replaced that.
>>
>> Only thing I can think of is the lambda sensor as the cars done about
>> 120k miles on the original so was wondering if that could be on its
>> way out and slow at sending the correct signal to increase fuelling at
>> top end?
>>
> Has it got an air flow meter? Is it stuck?
That was my thought- maybe a MAP sensor of a MAF or whatever it uses to
measure airflow in. I'm not familiar with the setup on this engine though.
