A Cars forum. AutoBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AutoBanter forum » Auto makers » Audi
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Could this be a lambda issue?



 
 
Thread Tools Display Modes
  #11  
Old July 15th 09, 10:04 AM posted to uk.rec.cars.maintenance,alt.autos.audi
Duncan Wood[_3_]
external usenet poster
 
Posts: 37
Default Could this be a lambda issue?

On Wed, 15 Jul 2009 08:21:34 +0100, Chris Bartram
> wrote:

> 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.


It's got one. The normal plug it into Vag-Com applies butodds are it's an
air or fuel flow restriction.
Ads
  #12  
Old July 15th 09, 10:58 AM posted to uk.rec.cars.maintenance,alt.autos.audi
Tim..[_2_]
external usenet poster
 
Posts: 10
Default Could this be a lambda issue?


"Redwood" > wrote in message
...
> 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 / exhaust is mine. NOT Lambda sensor.

Or cam timing incorrect.

Tim.

>


  #13  
Old July 15th 09, 02:25 PM posted to uk.rec.cars.maintenance,alt.autos.audi
Redwood
external usenet poster
 
Posts: 14
Default Could this be a lambda issue?

"Duncan Wood" > wrote in message
newsp.uw3p5xwrhaghkf@lucy...
> On Wed, 15 Jul 2009 08:21:34 +0100, Chris Bartram
> > wrote:
>
>> 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.

>
> It's got one. The normal plug it into Vag-Com applies butodds are it's an
> air or fuel flow restriction.


Thanks for the replies, it does sound like a fuelling problem. I'll get
hold of a fuel pressure gauge and check the correct pressure is reaching the
injection unit. Autodata says to manually trigger the pump and reading
should be between 0.8 & 1.2 bar and hold at 0.5 bar after 5 mins. Should at
least rule out any filter, blockage or pump probs. It's got good pick up
if, for e.g, I knock it into 2nd gear to turn into a side road with a steep
incline. As soon as I press the throttle it will pull very well up hill from
low speed but get to a certain point and nothing much happens at the top end
of the throttle range.


  #14  
Old July 15th 09, 02:45 PM posted to uk.rec.cars.maintenance,alt.autos.audi
Dave Plowman (News)
external usenet poster
 
Posts: 1,533
Default Could this be a lambda issue?

In article >,
Redwood > wrote:
> Thanks for the replies, it does sound like a fuelling problem. I'll get
> hold of a fuel pressure gauge and check the correct pressure is
> reaching the injection unit. Autodata says to manually trigger the
> pump and reading should be between 0.8 & 1.2 bar and hold at 0.5 bar
> after 5 mins. Should at least rule out any filter, blockage or pump
> probs.


The fuel pressure effects the entire engine range. If it were wrong it
wouldn't idle properly either. I suppose a blocked filter could have more
effect at high demand, though.

The range of 0.8 - 1.2 bar seems awfully wide to me - on mine a couple of
PSI makes a big difference. Although of course the pressure does change
depending on engine vacuum. But I'd expect the static pressure to be much
more accurate than that.

--
*Real men don't waste their hormones growing hair

Dave Plowman London SW
To e-mail, change noise into sound.
  #15  
Old July 15th 09, 04:44 PM posted to uk.rec.cars.maintenance,alt.autos.audi
Duncan Wood[_3_]
external usenet poster
 
Posts: 37
Default Could this be a lambda issue?

On Wed, 15 Jul 2009 14:45:06 +0100, Dave Plowman (News)
> wrote:

> In article >,
> Redwood > wrote:
>> Thanks for the replies, it does sound like a fuelling problem. I'll get
>> hold of a fuel pressure gauge and check the correct pressure is
>> reaching the injection unit. Autodata says to manually trigger the
>> pump and reading should be between 0.8 & 1.2 bar and hold at 0.5 bar
>> after 5 mins. Should at least rule out any filter, blockage or pump
>> probs.

>
> The fuel pressure effects the entire engine range. If it were wrong it
> wouldn't idle properly either. I suppose a blocked filter could have more
> effect at high demand, though.
>


Yup, if the filters clogged they're fine at low demand & bad at full bore.

> The range of 0.8 - 1.2 bar seems awfully wide to me - on mine a couple of
> PSI makes a big difference. Although of course the pressure does change
> depending on engine vacuum. But I'd expect the static pressure to be much
> more accurate than that.
>


1 bar sounds low anyway.
  #16  
Old July 15th 09, 06:11 PM posted to uk.rec.cars.maintenance,alt.autos.audi
Dave Plowman (News)
external usenet poster
 
Posts: 1,533
Default Could this be a lambda issue?

In article <op.uw38osczhaghkf@lucy>,
Duncan Wood > wrote:
> > The range of 0.8 - 1.2 bar seems awfully wide to me - on mine a couple
> > of PSI makes a big difference. Although of course the pressure does
> > change depending on engine vacuum. But I'd expect the static pressure
> > to be much more accurate than that.
> >


> 1 bar sounds low anyway.


Indeed. My old SD1 runs at 36 psi - and most modern vehicles are higher.

--
*You sound reasonable......time to up my medication

Dave Plowman London SW
To e-mail, change noise into sound.
  #17  
Old July 15th 09, 06:30 PM posted to uk.rec.cars.maintenance,alt.autos.audi
Redwood
external usenet poster
 
Posts: 14
Default Could this be a lambda issue?

"Duncan Wood" > wrote in message
newsp.uw38osczhaghkf@lucy...
> On Wed, 15 Jul 2009 14:45:06 +0100, Dave Plowman (News)
> > wrote:
>
>> In article >,
>> Redwood > wrote:
>>> Thanks for the replies, it does sound like a fuelling problem. I'll get
>>> hold of a fuel pressure gauge and check the correct pressure is
>>> reaching the injection unit. Autodata says to manually trigger the
>>> pump and reading should be between 0.8 & 1.2 bar and hold at 0.5 bar
>>> after 5 mins. Should at least rule out any filter, blockage or pump
>>> probs.

>>
>> The fuel pressure effects the entire engine range. If it were wrong it
>> wouldn't idle properly either. I suppose a blocked filter could have more
>> effect at high demand, though.
>>

>
> Yup, if the filters clogged they're fine at low demand & bad at full bore.
>
>> The range of 0.8 - 1.2 bar seems awfully wide to me - on mine a couple of
>> PSI makes a big difference. Although of course the pressure does change
>> depending on engine vacuum. But I'd expect the static pressure to be much
>> more accurate than that.
>>

>
> 1 bar sounds low anyway.


Got a fuel filter ordered for tomorrow. I'm assured it's had all filters
changed at every yearly service, but with the fuel filter hidden away under
the back end somewhere I will make sure & fit a new one anyway. The 1 bar
figure is the regulated pressure when measured with the gauge fitted inline
between the fuel inlet pipe & the injection unit - if that sounds more
feasible.


  #18  
Old July 15th 09, 09:07 PM posted to uk.rec.cars.maintenance,alt.autos.audi
[email protected]
external usenet poster
 
Posts: 1
Default Could this be a lambda issue?

On Wed, 15 Jul 2009 18:30:22 +0100, "Redwood" > wrote:

>"Duncan Wood" > wrote in message
>newsp.uw38osczhaghkf@lucy..


>> 1 bar sounds low anyway.

>
>Got a fuel filter ordered for tomorrow. I'm assured it's had all filters
>changed at every yearly service, but with the fuel filter hidden away under
>the back end somewhere I will make sure & fit a new one anyway. The 1 bar
>figure is the regulated pressure when measured with the gauge fitted inline
>between the fuel inlet pipe & the injection unit - if that sounds more
>feasible.
>


One Bar is about right for a SPI system. They run much lower than MPI.

Graham
  #19  
Old July 16th 09, 12:13 AM posted to uk.rec.cars.maintenance,alt.autos.audi
Dave Plowman (News)
external usenet poster
 
Posts: 1,533
Default Could this be a lambda issue?

In article >,
> wrote:
> One Bar is about right for a SPI system. They run much lower than MPI.


Didn't realise Audi ever used a SPI system - although the OP did say so.

--
*A woman drove me to drink and I didn't have the decency to thank her

Dave Plowman London SW
To e-mail, change noise into sound.
  #20  
Old July 16th 09, 02:36 PM posted to uk.rec.cars.maintenance,alt.autos.audi
Doki
external usenet poster
 
Posts: 10
Default Could this be a lambda issue?


"Redwood" > wrote in message
...
> 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?


I'd thrash the hell out of it for a while and see if it picks up...

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
1925 Lancia Lambda RonandRachel Auto Photos 0 February 9th 09 07:58 AM
320i Lambda Drawing Request Scott Buchanan BMW 0 January 27th 08 04:58 PM
Q:How to check Lambda? Asus BMW 4 August 21st 05 09:51 PM
how can i tell location of lambda sensor b1 s1 ? blueyo Audi 0 March 5th 05 06:40 PM
Catalytic Convertor Lambda Probe Ian Gaskell Audi 0 May 21st 04 05:14 PM


All times are GMT +1. The time now is 04:39 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AutoBanter.
The comments are property of their posters.