Vauxhall Astra SXi judder

Hi

I have a problem with my 2002 Astra 16v SXi (30,000 miles on clock), I
believe the symptoms are connected. When cruising along, if I go to give it
a small amount of throttle (just to maintain speed) the car judders, as
though the engine can't make up it's mind if it should be starting to
accelerate or not. When in slow moving traffic in first gear if I am only
just giving it a small amount of throttle to move along (around 1500 revs),
the car can suddenly seem to cut out with the result I suddenly slow down
although it doesn't stall, it's then 'bouncy' for several seconds
afterwards. It will do this in all gears but being in 1st gear in slow
moving traffic with a judder is much more noticeable when the revs drop and
it's like slamming on the brakes but with no brake lights to warn anyone
behind! The problem is always when I just very slightly accelerate and it's
the same if the car is hot or cold. It's only just started doing this and
seems to be getting worse.

The car is LPG and Petrol with the problem on both fuel types. A search on
the net seemed to point to the EGR value but I believe the ECOTEK engines on
newer models did away with this?

Any ideas what might be causing this problem before I take it to the garage
so I have some idea what they should be looking at.

Regards

Phil

 

ERG
MAF sensor
ICV

i'd go for the idle control valve first if fitted.

easy to do.

this should give you the idea:

http://82.34.50.33/sytemsandsoftwar...automotive/How_to/General/ecotecidlevalve.htm

mike

 

Hi

Thanks for the info, will give it a go.

Regards

Phil

 

First place I would look with a gas powered car is ignition system. LPG will
throw up any weaknesses you have in that area.
common problems are timing issues-gas needs advancing about 8-10 degrees
past the petrol setting. Another area is ht leads.
If your engine has them instead of the coil pack arrangement then try
re-routing them so they do not touch each other. When the insulation starts
to break down or get a bit damp, or even just under load they can arc to
ground, causing the plug not to fire, or worse case is arcing to another
lead and firing the wrong plug at the wrong time! If you are really unlucky
it fires the plug on the induction stroke and causes a premature explosion
in the cylinder and inlet manifold because the inlet valve is open and the
flame spreads. this usually means kissing goodbye to your airflow meter!

Mike

 

Have you any engine warning lights coming on?
Could be a misfire. If it is doing it on both fuels then I would suspect DIS
coil pack, plugs or if you are really unlucky TCU module on LPG.
You need to get it sorted soon cos if you fry your cat it will cost you a
fortune.

 

Hi Mike

Thanks for the reply. I was thinking it could be the ignition system but it
only happens when I slightly accelerate, i.e. go from coasting to just
touching the accelerator it will judder, it's as though the engine can't
decide if it should be going or not, but when I accerelate harder rather
than just a trickle to maintain speed, or drive up hill etc there is never a
problem, which sort of made me think it might be something else as the
judder only happens in very specific scenerios and I know when it will
happen now. The judder only lasts a few seconds and only happens with very
light acceleration, putting my foot down and it's as smooth as anything.
The LPG system is a Vauxhall fitted one and it does the same thing on
petrol, no HT leads.

I take your point about getting it looked at, however whenever I have had
these sorts of odd problems I have never found a garage ever fix it first go
and you end up going back half a dozen times each time costing a fortune,
hence trying to get all the info I can, so thanks for the advice.

There has never been any indication of a problem from the engine management
light, which means the garage will be clueless quite likely!

I'll let you know how I get on.

Regards

Phil

 

Hi

Thanks for the info.

No management warning lights.

I'll phone up the garage and book it in. Would it be the ignition system?
There is nothing random about the judder as it happens in the same places on
the way home from work, always after coasting along then just accelerating
very slightly or while slowly moving in traffic, again when just touching
the accelerator? Idle is completely steady, it never stalls and no starting
problems, just this hesitation on very slight acceleration.

Regards

Phil

 

Hi

Just had a look at the car and removed the top plastic ECOTEK cover. First
thing I noticed is part of the wiring loom was warn away exposing some wires
and the copper of an orange wire! This had be worn away due to the ECOTEK
cover screws being overtightened at some point (I had thought since having
the car it never seem quite fitted correctly) dislodging a rubber grommet
that holds the cover clear of the engine. Without the grommet in place the
cover was tightened down too far and so it's edge sat on top of the wiring
loom. What disgusts me is this car has been serviced by a Vauxhall garage,
the last time only a couple of months ago and they replaced spark plugs so
had this top off, and no mechanic has thought to sort it out or seen the
wear on the wiring loom and it's very easy to spot! It took me 5 minutes to
reseat the rubber grommet and have it fitted back properly. I don't think
that is a cause of my problems as the small amount of exposed copper was
only touching the plastic and not shorting against anything.

I removed the coil pack, it was all very clean and will see about swapping
it was a friends Astra now that I know how easy they are to get at, but what
was odd, on loosening one of the screws, (far left one) I could hear a hiss
of escaping air as it was first turned.

Just adding to this thread really to moan about that fact the cover wasn't
fitted correctly and could have potentially caused me a breakdown.

Regards

Phil

 

If you have access to a donor car try swapping the air mass meter if the
coil pack doesn't help.

 

Has the car had the upgraded software with the EGR valve written out?

Cheers

D

 

This is interesting. I hadn't heard of this before. Can you point me to any
links please



Thanks

 

Hi

I've since read about this although not sure it applies to the 16v 1.6, only
the 8v seems to be involved with this change. I've removed the EGR valve
for a clean (it hadn't been blocked off), it looked okay and appeared closed
rather than stuck open and on my model it has the 4 wire connection so if it
gets stuck it "should" trigger an engine management fault, which I've seen
none. I will see if it seems any better for having had a clean and a squirt
of lubricant and will ask the Vauxhall garage about it, but shouldn't they
have picked this up on a service, the last being only a few months ago? It
is a 2002 model and someone reported that at some point the firmware was
updated to "chatter" the valve periodically to stop it becoming dirty and
stuck so removing the need for the fix. Of course you read so many things
on the internet you never know what is correct or not.

Regards

Phil

 

Hi

Just for future people searching on a similar problem an update to what has
happened.

After removing and cleaning/spraying with lubricant the EGR valve it's been
like driving a new car. The judder/hesitation has gone, it pulls away
smoothly and it accelerates so much better, it's a pleasure to drive again.

As it seems a clean/oil is only ever a short term fix I have ordered a new
EGR valve. Your mileage may vary but at least my mileage is judder free now


Regards

Phil