328 'grabs' when stopping at slow speed.

I have an N-reg BMW 328 SE Auto. My local garage recently replaced a
broken air hose somewhere which had suddenly started causing stalling
(wouldn't idle). And I took the opportunity to have a routine service
done, as the 'Inspection' indicators indicated it was due.

But now, when stopping at slow speed (e.g. edging forward in traffic),
I can no longer brake to a truly smooth halt. At the very last moment,
there's a short but sharp 'grab'.

Idling is now about 750 rpm instead of the 600 I recall, but I'm
assured both by my garage and from replies to a similar post over at
uk.rec.cars.maintenance that this is correct. But this definitely
makes my car less pleasant to drive. I took it back; mechanic came out
with me, acknowledged the behaviour, can't explain it, and says he'll
speak to Vines in nearby Crawley. Meanwhile, can anyone suggest a
likely cause please?



--
Terry, West Sussex, UK

In ,
Terry Pinnell > typed:
> I have an N-reg BMW 328 SE Auto. My local garage recently replaced a
> broken air hose somewhere which had suddenly started causing stalling
> (wouldn't idle). And I took the opportunity to have a routine service
> done, as the 'Inspection' indicators indicated it was due.
>
> But now, when stopping at slow speed (e.g. edging forward in traffic),
> I can no longer brake to a truly smooth halt. At the very last moment,
> there's a short but sharp 'grab'.
>
> Idling is now about 750 rpm instead of the 600 I recall, but I'm
> assured both by my garage and from replies to a similar post over at
> uk.rec.cars.maintenance that this is correct. But this definitely
> makes my car less pleasant to drive. I took it back; mechanic came out
> with me, acknowledged the behaviour, can't explain it, and says he'll
> speak to Vines in nearby Crawley. Meanwhile, can anyone suggest a
> likely cause please?

I'd try ACE Automotive near Billingshurst, West Sussex

Sorted out my E34 525i a treat.

Give Dale a call on 01403 701845

Jason Russell

In article >,
Terry Pinnell > wrote:
> I have an N-reg BMW 328 SE Auto. My local garage recently replaced a
> broken air hose somewhere which had suddenly started causing stalling
> (wouldn't idle). And I took the opportunity to have a routine service
> done, as the 'Inspection' indicators indicated it was due.

> But now, when stopping at slow speed (e.g. edging forward in traffic),
> I can no longer brake to a truly smooth halt. At the very last moment,
> there's a short but sharp 'grab'.

I gave you the likely cause last time you posted this. Why start a new
thread? And did you have the check I suggested done?

--
*Never test the depth of the water with both feet.*

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" > wrote:

>In article >,
> Terry Pinnell > wrote:
>> I have an N-reg BMW 328 SE Auto. My local garage recently replaced a
>> broken air hose somewhere which had suddenly started causing stalling
>> (wouldn't idle). And I took the opportunity to have a routine service
>> done, as the 'Inspection' indicators indicated it was due.
>
>> But now, when stopping at slow speed (e.g. edging forward in traffic),
>> I can no longer brake to a truly smooth halt. At the very last moment,
>> there's a short but sharp 'grab'.
>
>I gave you the likely cause last time you posted this. Why start a new
>thread? And did you have the check I suggested done?


Here's your reply from uk.rec.cars.maintenance in full, so others know
what we're on about:
---------
"Is this the roll out change to first gear? If so, sounds like the
idle sensor is out of adjustment - on my 528 if you come to a halt
with your foor still on the throttle even slightly - by left foot
braking - you'll get a thump into first.

Try pulling the throttle *up* with your foot and see if this makes a
difference. It might just be cable adjustment - if indeed it has a
cable."
---------

I wasn't sure I understood some of your points. For a start, what is a
'roll out change to first gear'? The behaviour I described is a short
'grab', as if brake pads suddenly lock, not a gear change. As I
mentioned, it's when edging forward in a traffic jam. Typical speed
probably well under 1 mph. And, as I said, I'd been told by the garage
(who said they'd checked with BMW) that idling speed was correct.

Also, I can find no cable adjustment. The pedal rests on some sort of
roller, but the lever is out of sight and I see nothing emerging at
that (very low) location inside the engine compartment. The mechanic
who came out with me muttered something vague about 'all done by
computer', but frankly I'm no longer confident in him.

There's no way I can pull the throttle up. Trying to do so makes no
difference to idle speed, and indeed I couldn't detect any movement of
the pedal; seems to be prevented from moving backwards.

I suspect it's just my ignorance of the terminology. I'll try quoting
your reply verbatim to my garage - but sooner or later it looks as if
I'd better get to a BMW dealer, which I'm beginning to regret not
doing at the outset. (The local garage is literally 5 mins walk, so
very hard to resist, especially when they claimed 'very familiar with
servicing BMWs'!)

--
Terry, West Sussex, UK

In article >,
Terry Pinnell > wrote:
> >I gave you the likely cause last time you posted this. Why start a new
> >thread? And did you have the check I suggested done?


> Here's your reply from uk.rec.cars.maintenance in full, so others know
> what we're on about:
> ---------
> "Is this the roll out change to first gear? If so, sounds like the
> idle sensor is out of adjustment - on my 528 if you come to a halt
> with your foor still on the throttle even slightly - by left foot
> braking - you'll get a thump into first.

> Try pulling the throttle *up* with your foot and see if this makes a
> difference. It might just be cable adjustment - if indeed it has a
> cable."
> ---------

> I wasn't sure I understood some of your points. For a start, what is a
> 'roll out change to first gear'?

It's the gearbox changing down as you roll to a halt.

> The behaviour I described is a short
> 'grab', as if brake pads suddenly lock, not a gear change.

But that's exactly what it feels like. It 'thumps' into first gear.

> As I mentioned, it's when edging forward in a traffic jam.

Now hang on - edging forward, or slowing down?

> Typical speed probably well under 1 mph. And, as I said, I'd been told
> by the garage (who said they'd checked with BMW) that idling speed was
> correct.

It's not exactly to do with that.

> Also, I can find no cable adjustment. The pedal rests on some sort of
> roller, but the lever is out of sight and I see nothing emerging at
> that (very low) location inside the engine compartment. The mechanic
> who came out with me muttered something vague about 'all done by
> computer', but frankly I'm no longer confident in him.

The gearbox is told in some way when the engine is at idle. And it's not
by the actual speed, as this of course varies slightly - cold or AC on.

> There's no way I can pull the throttle up. Trying to do so makes no
> difference to idle speed, and indeed I couldn't detect any movement of
> the pedal; seems to be prevented from moving backwards.

It was just a thought - but I'm not sure where the sensor that tells the
gearbox the throttle is closed is - quite likely part of the TPS etc.

> I suspect it's just my ignorance of the terminology. I'll try quoting
> your reply verbatim to my garage - but sooner or later it looks as if
> I'd better get to a BMW dealer, which I'm beginning to regret not
> doing at the outset. (The local garage is literally 5 mins walk, so
> very hard to resist, especially when they claimed 'very familiar with
> servicing BMWs'!)

You might do better with an auto specialist.

But make sure you go out in the car with a mechanic and demonstrate the
fault.

All I'm saying is your symptoms are *exactly* the same as I get on my ZF
auto if you left foot brake and keep a whiff of throttle on. It thumps
*badly* as it comes to rest and changes to first.

Thinks. Is it a Steptronic? Or can you select a second gear start? This
would soon show if my theory is correct.

--
*If you can read this, thank a teecher

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" > wrote:

>In article >,
> Terry Pinnell > wrote:
>> >I gave you the likely cause last time you posted this. Why start a new
>> >thread? And did you have the check I suggested done?
>
>
>> Here's your reply from uk.rec.cars.maintenance in full, so others know
>> what we're on about:
>> ---------
>> "Is this the roll out change to first gear? If so, sounds like the
>> idle sensor is out of adjustment - on my 528 if you come to a halt
>> with your foor still on the throttle even slightly - by left foot
>> braking - you'll get a thump into first.
>
>> Try pulling the throttle *up* with your foot and see if this makes a
>> difference. It might just be cable adjustment - if indeed it has a
>> cable."
>> ---------
>
>> I wasn't sure I understood some of your points. For a start, what is a
>> 'roll out change to first gear'?
>
>It's the gearbox changing down as you roll to a halt.

OK, understood now thanks.

>> The behaviour I described is a short
>> 'grab', as if brake pads suddenly lock, not a gear change.
>
>But that's exactly what it feels like. It 'thumps' into first gear.
>
>> As I mentioned, it's when edging forward in a traffic jam.
>
>Now hang on - edging forward, or slowing down?

Well, both! The 'grab' obviously happens after 'accelerating' to about
1-5 mph from the nth stop during a couple of miles worth of M25
traffic jam, and braking seconds later to the (n+1)th stop.

>> Typical speed probably well under 1 mph. And, as I said, I'd been told
>> by the garage (who said they'd checked with BMW) that idling speed was
>> correct.
>
>It's not exactly to do with that.
>
>> Also, I can find no cable adjustment. The pedal rests on some sort of
>> roller, but the lever is out of sight and I see nothing emerging at
>> that (very low) location inside the engine compartment. The mechanic
>> who came out with me muttered something vague about 'all done by
>> computer', but frankly I'm no longer confident in him.
>
>The gearbox is told in some way when the engine is at idle. And it's not
>by the actual speed, as this of course varies slightly - cold or AC on.

>> There's no way I can pull the throttle up. Trying to do so makes no
>> difference to idle speed, and indeed I couldn't detect any movement of
>> the pedal; seems to be prevented from moving backwards.
>
>It was just a thought - but I'm not sure where the sensor that tells the
>gearbox the throttle is closed is - quite likely part of the TPS etc.

TPS? Transmission Programming System?

>> I suspect it's just my ignorance of the terminology. I'll try quoting
>> your reply verbatim to my garage - but sooner or later it looks as if
>> I'd better get to a BMW dealer, which I'm beginning to regret not
>> doing at the outset. (The local garage is literally 5 mins walk, so
>> very hard to resist, especially when they claimed 'very familiar with
>> servicing BMWs'!)
>
>You might do better with an auto specialist.
>
>But make sure you go out in the car with a mechanic and demonstrate the
>fault.
>
>All I'm saying is your symptoms are *exactly* the same as I get on my ZF
>auto if you left foot brake and keep a whiff of throttle on. It thumps
>*badly* as it comes to rest and changes to first.

The failure of the mechanic to mention any of this clearly means he's
not truly qualified on the BMW finer points. When I took it back they
'cleaned the carbs and jets' (I think those were his words), and
'checked the idle speed, and couldn't find anything wrong.' As I
mentioned, he didn't argue that something was amiss when he
accompanied me shortly after for a run. His stated intention (Monday)
was to speak to Vines. However, he was apparently off ill for a day,
so I'll give it till Monday before chasing again. Don't really want to
let the local garage off the hook, as that cost me £258.

>Thinks. Is it a Steptronic? Or can you select a second gear start? This
>would soon show if my theory is correct.

Pretty sure I can start in 2nd. I'll check and report back.

When I tried it this morning (to check your 'pedal up' suggestion) one
thing I did establish was that I could virtually eliminate that final
'grab' by quickly easing off the brake at the very last moment. So
maybe I'm making heavy weather of this? Or maybe it really is nothing
to do with idling, and somehow a brakes or brake pad issue? But then,
what has changed? This routine 'Inspection Service' didn't touch the
brakes.

One other possibility is that maybe I've had a small split in that
'air hose' for years, and that somehow reduced the idling speed. Only
after its complete failure and replacement id my idling speed now
'correct', necessitating a new driving style?

--
Terry, West Sussex, UK

In article >,
Terry Pinnell > wrote:
> >> I wasn't sure I understood some of your points. For a start, what is a
> >> 'roll out change to first gear'?
> >
> >It's the gearbox changing down as you roll to a halt.

> OK, understood now thanks.

> >> The behaviour I described is a short
> >> 'grab', as if brake pads suddenly lock, not a gear change.
> >
> >But that's exactly what it feels like. It 'thumps' into first gear.
> >
> >> As I mentioned, it's when edging forward in a traffic jam.
> >
> >Now hang on - edging forward, or slowing down?

> Well, both! The 'grab' obviously happens after 'accelerating' to about
> 1-5 mph from the nth stop during a couple of miles worth of M25
> traffic jam, and braking seconds later to the (n+1)th stop.

But it only happens when slowing, not speeding up? Obviously you can't
slow without speeding up first, but I'm interested in when the grab
actually occurs.

> >> Typical speed probably well under 1 mph. And, as I said, I'd been told
> >> by the garage (who said they'd checked with BMW) that idling speed was
> >> correct.
> >
> >It's not exactly to do with that.
> >
> >> Also, I can find no cable adjustment. The pedal rests on some sort of
> >> roller, but the lever is out of sight and I see nothing emerging at
> >> that (very low) location inside the engine compartment. The mechanic
> >> who came out with me muttered something vague about 'all done by
> >> computer', but frankly I'm no longer confident in him.
> >
> >The gearbox is told in some way when the engine is at idle. And it's not
> >by the actual speed, as this of course varies slightly - cold or AC on.

> >> There's no way I can pull the throttle up. Trying to do so makes no
> >> difference to idle speed, and indeed I couldn't detect any movement of
> >> the pedal; seems to be prevented from moving backwards.
> >
> >It was just a thought - but I'm not sure where the sensor that tells the
> >gearbox the throttle is closed is - quite likely part of the TPS etc.

> TPS? Transmission Programming System?

Sorry - throttle position sensor.

> >> I suspect it's just my ignorance of the terminology. I'll try quoting
> >> your reply verbatim to my garage - but sooner or later it looks as if
> >> I'd better get to a BMW dealer, which I'm beginning to regret not
> >> doing at the outset. (The local garage is literally 5 mins walk, so
> >> very hard to resist, especially when they claimed 'very familiar with
> >> servicing BMWs'!)
> >
> >You might do better with an auto specialist.
> >
> >But make sure you go out in the car with a mechanic and demonstrate the
> >fault.
> >
> >All I'm saying is your symptoms are *exactly* the same as I get on my ZF
> >auto if you left foot brake and keep a whiff of throttle on. It thumps
> >*badly* as it comes to rest and changes to first.

> The failure of the mechanic to mention any of this clearly means he's
> not truly qualified on the BMW finer points. When I took it back they
> 'cleaned the carbs and jets' (I think those were his words),

I hope not as it has neither. It has fuel injection.

> and 'checked the idle speed, and couldn't find anything wrong.' As I
> mentioned, he didn't argue that something was amiss when he accompanied
> me shortly after for a run. His stated intention (Monday) was to speak
> to Vines. However, he was apparently off ill for a day, so I'll give it
> till Monday before chasing again. Don't really want to let the local
> garage off the hook, as that cost me £258.

Yes. It's always annoying when a fault isn't fixed.

> >Thinks. Is it a Steptronic? Or can you select a second gear start? This
> >would soon show if my theory is correct.

> Pretty sure I can start in 2nd. I'll check and report back.

> When I tried it this morning (to check your 'pedal up' suggestion) one
> thing I did establish was that I could virtually eliminate that final
> 'grab' by quickly easing off the brake at the very last moment. So
> maybe I'm making heavy weather of this? Or maybe it really is nothing
> to do with idling, and somehow a brakes or brake pad issue? But then,
> what has changed? This routine 'Inspection Service' didn't touch the
> brakes.

Well, the symptom I'm describing on my car requires both the brake and
accelerator to be depressed at once - and the accelerator only by a tiny
amount. Release either and the thump doesn't happen.

> One other possibility is that maybe I've had a small split in that
> 'air hose' for years, and that somehow reduced the idling speed. Only
> after its complete failure and replacement id my idling speed now
> 'correct', necessitating a new driving style?

I'd have thought you'd have seen an alteration of the idle speed on the
rev counter?

--
*The average person falls asleep in seven minutes *

Dave Plowman London SW
To e-mail, change noise into sound.

Terry Pinnell > wrote:

>"Dave Plowman (News)" > wrote:
>
>>In article >,
>> Terry Pinnell > wrote:
>>> >I gave you the likely cause last time you posted this. Why start a new
>>> >thread? And did you have the check I suggested done?
>>
>>
>>> Here's your reply from uk.rec.cars.maintenance in full, so others know
>>> what we're on about:
>>> ---------
>>> "Is this the roll out change to first gear? If so, sounds like the
>>> idle sensor is out of adjustment - on my 528 if you come to a halt
>>> with your foor still on the throttle even slightly - by left foot
>>> braking - you'll get a thump into first.
>>
>>> Try pulling the throttle *up* with your foot and see if this makes a
>>> difference. It might just be cable adjustment - if indeed it has a
>>> cable."
>>> ---------
>>
>>> I wasn't sure I understood some of your points. For a start, what is a
>>> 'roll out change to first gear'?
>>
>>It's the gearbox changing down as you roll to a halt.
>
>OK, understood now thanks.
>
>>> The behaviour I described is a short
>>> 'grab', as if brake pads suddenly lock, not a gear change.
>>
>>But that's exactly what it feels like. It 'thumps' into first gear.
>>
>>> As I mentioned, it's when edging forward in a traffic jam.
>>
>>Now hang on - edging forward, or slowing down?
>
>Well, both! The 'grab' obviously happens after 'accelerating' to about
>1-5 mph from the nth stop during a couple of miles worth of M25
>traffic jam, and braking seconds later to the (n+1)th stop.
>
>>> Typical speed probably well under 1 mph. And, as I said, I'd been told
>>> by the garage (who said they'd checked with BMW) that idling speed was
>>> correct.
>>
>>It's not exactly to do with that.
>>
>>> Also, I can find no cable adjustment. The pedal rests on some sort of
>>> roller, but the lever is out of sight and I see nothing emerging at
>>> that (very low) location inside the engine compartment. The mechanic
>>> who came out with me muttered something vague about 'all done by
>>> computer', but frankly I'm no longer confident in him.
>>
>>The gearbox is told in some way when the engine is at idle. And it's not
>>by the actual speed, as this of course varies slightly - cold or AC on.
>
>>> There's no way I can pull the throttle up. Trying to do so makes no
>>> difference to idle speed, and indeed I couldn't detect any movement of
>>> the pedal; seems to be prevented from moving backwards.
>>
>>It was just a thought - but I'm not sure where the sensor that tells the
>>gearbox the throttle is closed is - quite likely part of the TPS etc.
>
>TPS? Transmission Programming System?
>
>>> I suspect it's just my ignorance of the terminology. I'll try quoting
>>> your reply verbatim to my garage - but sooner or later it looks as if
>>> I'd better get to a BMW dealer, which I'm beginning to regret not
>>> doing at the outset. (The local garage is literally 5 mins walk, so
>>> very hard to resist, especially when they claimed 'very familiar with
>>> servicing BMWs'!)
>>
>>You might do better with an auto specialist.
>>
>>But make sure you go out in the car with a mechanic and demonstrate the
>>fault.
>>
>>All I'm saying is your symptoms are *exactly* the same as I get on my ZF
>>auto if you left foot brake and keep a whiff of throttle on. It thumps
>>*badly* as it comes to rest and changes to first.
>
>The failure of the mechanic to mention any of this clearly means he's
>not truly qualified on the BMW finer points. When I took it back they
>'cleaned the carbs and jets' (I think those were his words), and
>'checked the idle speed, and couldn't find anything wrong.' As I
>mentioned, he didn't argue that something was amiss when he
>accompanied me shortly after for a run. His stated intention (Monday)
>was to speak to Vines. However, he was apparently off ill for a day,
>so I'll give it till Monday before chasing again. Don't really want to
>let the local garage off the hook, as that cost me £258.
>
>>Thinks. Is it a Steptronic? Or can you select a second gear start? This
>>would soon show if my theory is correct.
>
>Pretty sure I can start in 2nd. I'll check and report back.
>
>When I tried it this morning (to check your 'pedal up' suggestion) one
>thing I did establish was that I could virtually eliminate that final
>'grab' by quickly easing off the brake at the very last moment. So
>maybe I'm making heavy weather of this? Or maybe it really is nothing
>to do with idling, and somehow a brakes or brake pad issue? But then,
>what has changed? This routine 'Inspection Service' didn't touch the
>brakes.
>
>One other possibility is that maybe I've had a small split in that
>'air hose' for years, and that somehow reduced the idling speed. Only
>after its complete failure and replacement id my idling speed now
>'correct', necessitating a new driving style?

FWIW, it starts OK in second.

I had another conversation with the local mechanic this morning. The
gist was that the air hose split could have caused the computer to
change its settings. My obvious question was "So, after you replaced
the air hose, why didn't the computer change the settings again to
match the new fuel/air proportions?" He said something about the
computer possibly being faulty, but I didn't really follow. Make any
sense?

--
Terry, West Sussex, UK