Hi All,

A mate is trying to sort an Avensis, if you slowly take the revs up to
about 3k it starts dropping and rasing it's revs, like a boy racer
would, revving it at the lights? ;-(

He's scoped the injectors and they are definatly cutting in and out
(with the drop / raise in revs).

The camshaft sensor checks out ok, as did the map and throttle
position sensors.

The lamba sensor is running flat out all the time (above .9V) and he
has swapped out a coil with no change in symptoms.

Anyone know where he can get access to the crankshaft sensor and/or
has anyone seen this particular fault before please?

All the best ..

T i m

On Mon, 28 Jul 2008 13:39:05 GMT, news@spaced.me.uk (T i m) wrote:


>Anyone know where he can get access to the crankshaft sensor 

Update, he's found and scoped that now ... fine.

>and/or
>has anyone seen this particular fault before please?
>
>All the best ..
>
>T i m

"T i m"  wrote in message 
news:488dc919.23489796@news.btconnect.com...
> Hi All,
>
> A mate is trying to sort an Avensis, if you slowly take the revs up to
> about 3k it starts dropping and rasing it's revs, like a boy racer
> would, revving it at the lights? ;-(
>
> He's scoped the injectors and they are definatly cutting in and out
> (with the drop / raise in revs).
>
> The camshaft sensor checks out ok, as did the map and throttle
> position sensors.
>
> The lamba sensor is running flat out all the time (above .9V) and he
> has swapped out a coil with no change in symptoms.
>
> Anyone know where he can get access to the crankshaft sensor and/or
> has anyone seen this particular fault before please?
>
> All the best ..
>
> T i m
>
>

If the lambda is showing a constant 0.9v, then either it's broken (unlikely 
as they're far more likely to fail to 0v), or the ECU isn't entering into 
closed loop control.

I'd start by checking the coolant temp sensor, and for any obvious leaks 
around the inlet manifold.

"T i m"  wrote in message 
news:488dc919.23489796@news.btconnect.com...
> Hi All,
>
> A mate is trying to sort an Avensis, if you slowly take the revs up to
> about 3k it starts dropping and rasing it's revs, like a boy racer
> would, revving it at the lights? ;-(
>
> He's scoped the injectors and they are definatly cutting in and out
> (with the drop / raise in revs).
>
> The camshaft sensor checks out ok, as did the map and throttle
> position sensors.
>
> The lamba sensor is running flat out all the time (above .9V) and he
> has swapped out a coil with no change in symptoms.
>
> Anyone know where he can get access to the crankshaft sensor and/or
> has anyone seen this particular fault before please?

Check the intake trunking after the MAF for a split that is opening, and 
allowing un-metered air in...

tim..

On Mon, 28 Jul 2008 16:11:14 +0100, "moray"
 wrote:


>If the lambda is showing a constant 0.9v, then either it's broken (unlikely 
>as they're far more likely to fail to 0v), 

Ok thanks. An update on that is that he took the lambda sensor out,
cleaned it, gave it a tap and it seems to be behaving itself now.
However is has made no difference to the main fault.

>or the ECU isn't entering into 
>closed loop control.

That was his next thought and was considering sending it away for
testing.
>
>I'd start by checking the coolant temp sensor, 

He says he will check that (so thanks) but feels it may be ok as he
thinks it also runs the in car temp gauge (and that's ok)?

>and for any obvious leaks 
>around the inlet manifold. 

He's checked that but even with one of the big inlet pipes off it does
the same thing (suggesting it would have to be a pretty big leak)?

He will do some more checks and report back (thanks).

All the best ..

T i m

On Mon, 28 Jul 2008 17:30:14 +0100, "Tim.."
 wrote:


>Check the intake trunking after the MAF for a split that is opening, and 
>allowing un-metered air in...

Thanks for that Tim but he suggests this model is pre the MAF system?

All the best ..

T i m

"T i m"  wrote in message 
news:488f08df.19324796@news.btconnect.com...
> On Mon, 28 Jul 2008 17:30:14 +0100, "Tim.."
>  wrote:
>
>
>>Check the intake trunking after the MAF for a split that is opening, and
>>allowing un-metered air in...
>
> Thanks for that Tim but he suggests this model is pre the MAF system?
>

I may be wrong, but I am pretty sure Toyota never used a MAP system, so 
therefore you will find a hot wire or hot film mass air flow sensor on the 
airbox.

Tim..

On Tue, 29 Jul 2008 13:55:08 +0100, "Tim.."
 wrote:

>
>"T i m"  wrote in message 
>news:488f08df.19324796@news.btconnect.com...
>> On Mon, 28 Jul 2008 17:30:14 +0100, "Tim.."
>>  wrote:
>>
>>
>>>Check the intake trunking after the MAF for a split that is opening, and
>>>allowing un-metered air in...
>>
>> Thanks for that Tim but he suggests this model is pre the MAF system?
>>
>
>I may be wrong, but I am pretty sure Toyota never used a MAP system, so 
>therefore you will find a hot wire or hot film mass air flow sensor on the 
>airbox.

Hmmm, well, my mate seems pretty convinced it isn't a MAF system and
if it helps, I watched him use a hand vacuum pump to progressively put
a vacuum on a doodad up on the bulkhead and watch it's output go from
1 to 4 volts or so ... ?

There are some wires going into the airbox but we believe that is the
inlet air temperature sensor?

I've just looked with him and there are no other wies between there
and the throttle position sensor / idle control valve?

All the best ..

T i m

p.s. He has just shown me a loose MAF sensor and I can't see anything
like that in there either. :-(

"T i m"  wrote in message 
news:488f25e2.26751906@news.btconnect.com...
> On Tue, 29 Jul 2008 13:55:08 +0100, "Tim.."
>  wrote:
>
>>
>>"T i m"  wrote in message
>>news:488f08df.19324796@news.btconnect.com...
>>> On Mon, 28 Jul 2008 17:30:14 +0100, "Tim.."
>>>  wrote:
>>>
>>>
>>>>Check the intake trunking after the MAF for a split that is opening, and
>>>>allowing un-metered air in...
>>>
>>> Thanks for that Tim but he suggests this model is pre the MAF system?
>>>
>>
>>I may be wrong, but I am pretty sure Toyota never used a MAP system, so
>>therefore you will find a hot wire or hot film mass air flow sensor on the
>>airbox.
>
> Hmmm, well, my mate seems pretty convinced it isn't a MAF system and
> if it helps, I watched him use a hand vacuum pump to progressively put
> a vacuum on a doodad up on the bulkhead and watch it's output go from
> 1 to 4 volts or so ... ?
>
> There are some wires going into the airbox but we believe that is the
> inlet air temperature sensor?
>
> I've just looked with him and there are no other wies between there
> and the throttle position sensor / idle control valve?
>
> All the best ..
>
> T i m
>
> p.s. He has just shown me a loose MAF sensor and I can't see anything
> like that in there either. :-(

In which case, I stand corrected and it must be a MAP system, given your 
mate was miti-vacc-ing the map sensor!

You would be best to post *all* info over at 
http://www.bba-reman.co.uk/forums where the expert guys will be able to shed 
some of their knowledge.

Tim.

On Mon, 28 Jul 2008 16:11:14 +0100, "moray"
 wrote:


>I'd start by checking the coolant temp sensor,

Using the IR thermometer the temp of the engine was 40 deg C and at
that temp the temp sensor was ~2K ohms (within spec I believe).

All the best ..

T i m

On Tue, 29 Jul 2008 17:09:13 +0100, "Tim.."
 wrote:


>> p.s. He has just shown me a loose MAF sensor and I can't see anything
>> like that in there either. :-(
>
>In which case, I stand corrected and it must be a MAP system, given your 
>mate was miti-vacc-ing the map sensor!

;-)
>
>You would be best to post *all* info over at 
>http://www.bba-reman.co.uk/forums where the expert guys will be able to shed 
>some of their knowledge.

Oh, ok Tim, who are these folk please (I have looked at the link and
got through to a Forum etc).

All the best ..

T i m

T i m  gurgled happily, sounding much like they were
saying:
 
>>I'd start by checking the coolant temp sensor,

> Using the IR thermometer the temp of the engine was 40 deg C

What do you mean by "the temp of the engine"? What were you measuring?
The coolant temp sensor is dipped into the water jacket of the head and 
is measuring the temperature of the water as it passes around the head. 
It's very likely different elsewhere in the engine, and sure as hell 
different to the outside of the head.

On 29 Jul 2008 19:08:29 GMT, Adrian  wrote:

>T i m  gurgled happily, sounding much like they were
>saying:
> 
>>>I'd start by checking the coolant temp sensor,
>
>> Using the IR thermometer the temp of the engine was 40 deg C
>
>What do you mean by "the temp of the engine"? What were you measuring?
>The coolant temp sensor is dipped into the water jacket of the head and 
>is measuring the temperature of the water as it passes around the head. 
>It's very likely different elsewhere in the engine, and sure as hell 
>different to the outside of the head.

Fair enough, my point was with a warm engine [1], the resistance of
the temp sensor was within max / min range and looked 'good' on the
internal gauge (so wasn't actually faulty).

So, any idea what the actual fault is please Adrian?

All the best ..

T i m

[1] The general mass of the block rather than engine mount or some
other irrelevant place. ;-)