A couple of 'features' or are they faults?!

Faults and Technical chat for the Vauxhall Astra K
griffin79
Posts: 11
Joined: Sun Feb 02, 2020 6:09 pm
Astra Model: Griffin 1.4T 150PS
Astra Colour: Summit White

A couple of 'features' or are they faults?!

Post by griffin79 » Mon Feb 17, 2020 3:27 pm

Since picking up my nearly new Astra (sub 500 miles), I've noticed a few of things which I'm not sure are faults or not. I have the 1.4T 150PS.

1. Hesitant in 1st gear when pulling away. No matter how smooth I am on the clutch, it often jerks - not by a massive amount but enough to make it not be smooth and seem like I don't have very good clutch control! Happens when cold and warm.

2. When off the throttle and in gear i.e going down hill, the engine has a momentary stutter - almost the same sort of feeling as if you were to increase the cruise control speed very briefly and then cancel it. Happens when cold and warm.

3. On a number of occasions, I've driven the car, dipped the clutch and the engine is revving away @ 2k revs for 5 seconds or so before then idling back down to tick over. Only experienced this when warm.
Also when starting the car up it takes about 15-20 seconds (when cold) to drop the revs from 12/1300 rpm to idle @ around 900rpm. When warm it can still take 10 seconds. Most cars I've had have tended to drop the revs to idle significantly sooner.

Normal quirks for the 1.4T or perhaps still running in?!

Cheers.
Last edited by griffin79 on Mon Feb 17, 2020 5:04 pm, edited 1 time in total.

AdieMcc
Posts: 1630
Joined: Sun Oct 09, 2016 6:25 am
Astra Model: Astra K 1.4T 150
Astra Options: Reversing sensors
Astra Colour: Black

Re: A couple of 'features' or are they faults?!

Post by AdieMcc » Mon Feb 17, 2020 4:03 pm

Should ease off the more miles you put on.
Astra K 1.4T 150 Nav. Black,18" wheels, sensors front/back, heated seats/steering wheel, shark fin aerial, washed every 2 days :D

griffin79
Posts: 11
Joined: Sun Feb 02, 2020 6:09 pm
Astra Model: Griffin 1.4T 150PS
Astra Colour: Summit White

Re: A couple of 'features' or are they faults?!

Post by griffin79 » Mon Feb 17, 2020 5:20 pm

Thanks AdieMcc.
Slightly off topic, but I notice you have a sharks fin aerial. Is it hard to fit? Where do you get one? I have a genuine need for one, not just for looks, so it would be worth knowing! Cheers

Redman
Posts: 993
Joined: Sat Aug 20, 2016 7:16 pm
Astra Model: Astra elite nav 150
Astra Colour: red

Re: A couple of 'features' or are they faults?!

Post by Redman » Mon Feb 17, 2020 9:31 pm

I have a 19 plate 1.4t 150 and mine has all your 3 points. Points 1 and 3, I believe are part of the petrol particulate cleaning method and emissions control . When no fuel is going into the engine e.g. going down hill the vvt puts oxygen into the exhaust system heating it up to burn the particulates off (slightly brakes engine). Petrol exhausts run hotter than diesel engines and with adding oxygen increases exhaust temp. Petrol particulate filters clean differently to diesels.
Point 2 possibly slight turbo lag.

Redman
Posts: 993
Joined: Sat Aug 20, 2016 7:16 pm
Astra Model: Astra elite nav 150
Astra Colour: red

Re: A couple of 'features' or are they faults?!

Post by Redman » Tue Feb 18, 2020 7:45 am

Here is an explanation to gdi regeneration

GPF regeneration can only be performed in “non power” conditions,  meaning that regeneration is normally achieved under deceleration. Deceleration increases the amount of oxygen following through the engine and exhaust system. This in turn raises the temperature of the GPF to around 400c – 700c, igniting the soot contained within the filter. 

In conditions where this is not possible, the vehicles engine management systems alters timing causing it to run lean. This “lean” burn increases oxygen and therefore GPF operating temperatures, allowing a regeneration to occur.

Valer
Posts: 36
Joined: Thu Feb 28, 2019 4:42 pm

Re: A couple of 'features' or are they faults?!

Post by Valer » Tue Feb 18, 2020 11:09 am

This may be of interest regarding Vauxhall GPF

Q/What conditions are required for the GPF to begin active/dynamic regeneration?
The following conditions must be fulfilled for regeneration to begin.
• a.) Engine running since start > 2 min
• b.) Calculated soot load >100% (value dependent on variant and MY)
• c.) Coolant temperature between 50°C and 115°C (=normal operation temperature), other component
temperature as well.
• d.) No GPF-relevant faults stored in system.
• e.) moderate dynamic driving profile, but no full load driving

Important:
To assure Active regeneration durations below 30min moderate speed > 60 km/h is recommended.
Prolonged low speed driving may lead to much longer Active Regenerations

Q/Under what conditions is Active regeneration interrupted/ended once it has started?

Normally when regeneration has been successfully completed, or:
• a.) After a variant and model year maximum dependent regeneration time (approximately 60 minutes) is
reached
• b.) If the engine is switched off or has stalled.
• c.) If during regeneration, a fault is detected on the components relevant for combustion (injection/intake
system).
• d.) Extremely transient driving (alternating heavy accel and decels) over a longer period
Note:
If a regeneration is interrupted once started but before it has been completed to an application specific level <<100%,
the regeneration lamps/messages re - illuminate on the next engine start (cold or hot) and regeneration begins again
once the operating conditions have been fulfilled.

Q/How long does it take to complete an active/dynamic regeneration?

• a.)In the most favourable case?
Depending on variant and model year minimum 15 minutes under motorway/cross-country driving.
b.) In the most unfavourable case?
1. Vehicle conditions such as long down-hill descents, frequent driving in the low-load range (city driving,
idling) allow the exhaust temperature to fall. If the conditions for triggering regeneration were fulfilled,
the active regeneration time can be extended up to 60 minutes (depending on engine type). If
complete regeneration is not possible within this period, the regeneration will be interrupted.

Q/Does regeneration affect the oil life similar to diesel?
No, because fuel which might enter oil sump during regeneration attempt will vaporize soon. Therefore no oil dilution.

Q/Are intact GPF sensors important for the Active regeneration procedure?
Yes, defective sensors will generally trigger a DTC which will inhibit active regeneration.

Redman
Posts: 993
Joined: Sat Aug 20, 2016 7:16 pm
Astra Model: Astra elite nav 150
Astra Colour: red

Re: A couple of 'features' or are they faults?!

Post by Redman » Tue Feb 18, 2020 11:54 am

That is good info Valer.

I am on the understanding most of the regeneration is done passively.

Calculated soot must be worked out similar to oil life I suppose, taking in to account how much passive regeneration conditions have been met and performed successfully etc.

I had a 16 plate 1.4t 150 from new and I didn't get the car stuttering down hill occasionally when fuel addition is off, or revving high suddenly. This prompted me to research the gpf a bit more.

Valer
Posts: 36
Joined: Thu Feb 28, 2019 4:42 pm

Re: A couple of 'features' or are they faults?!

Post by Valer » Tue Feb 18, 2020 1:33 pm

Redman wrote:
Tue Feb 18, 2020 11:54 am
That is good info Valer.

I am on the understanding most of the regeneration is done passively.

Calculated soot must be worked out similar to oil life I suppose, taking in to account how much passive regeneration conditions have been met and performed successfully etc.

I had a 16 plate 1.4t 150 from new and I didn't get the car stuttering down hill occasionally when fuel addition is off, or revving high suddenly. This prompted me to research the gpf a bit more.
The Q/A is from a Vx bulletin for technicians,i've no experience of GPF systems yet but the soot loading will no doubt take quite a few parameters into account,the system is very similar to the DPF on diesels which we all know and love ;) :lol:
It does have 2 temperature sensors and a pressure sensor to help with calculated soot loading and the pressure reading will be be an important factor in the calculation.

Stanreed
Posts: 7
Joined: Fri Mar 30, 2018 12:15 pm

Re: A couple of 'features' or are they faults?!

Post by Stanreed » Tue Feb 18, 2020 4:54 pm

griffin79 wrote:
Mon Feb 17, 2020 3:27 pm
Since picking up my nearly new Astra (sub 500 miles), I've noticed a few of things which I'm not sure are faults or not. I have the 1.4T 150PS.

1. Hesitant in 1st gear when pulling away. No matter how smooth I am on the clutch, it often jerks - not by a massive amount but enough to make it not be smooth and seem like I don't have very good clutch control! Happens when cold and warm.

2. When off the throttle and in gear i.e going down hill, the engine has a momentary stutter - almost the same sort of feeling as if you were to increase the cruise control speed very briefly and then cancel it. Happens when cold and warm.

3. On a number of occasions, I've driven the car, dipped the clutch and the engine is revving away @ 2k revs for 5 seconds or so before then idling back down to tick over. Only experienced this when warm.
Also when starting the car up it takes about 15-20 seconds (when cold) to drop the revs from 12/1300 rpm to idle @ around 900rpm. When warm it can still take 10 seconds. Most cars I've had have tended to drop the revs to idle significantly sooner.

Normal quirks for the 1.4T or perhaps still running in?!

Cheers.
I have the three problems you expose and my car is MY16 150PS.

MisterEChops
Posts: 60
Joined: Tue Oct 08, 2019 12:00 am

Re: A couple of 'features' or are they faults?!

Post by MisterEChops » Wed Feb 19, 2020 11:01 pm

griffin79 wrote:
Mon Feb 17, 2020 3:27 pm
1. Hesitant in 1st gear when pulling away. No matter how smooth I am on the clutch, it often jerks - not by a massive amount but enough to make it not be smooth and seem like I don't have very good clutch control! Happens when cold and warm.
You should move your seat either closer or further away, sounds like your reach of the clutch may be incorrect.

The other thing? Torque is severely limited in 1st gear to protect the clutch, just put the car into sport mode and this limitation is gone... but driveability is definitely downgraded over all.

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