Not a Vectra but my wifes Astra is pinking

[spatch]

I know this is not a Vectra but I want to pick peoples brains here on this forum.

The car is an Astra 1.6 16V Elegance. The problem, as the title suggests, is that it is pinking, but only when the clutch is being engaged whilst changing up gear. As soon as the clutch is fully engaged the pinking stops. It must have something to do with too much advance when initially under load as the clutch is engaged.

In the olden days you could just retard the distributor but this is obviously not an option here. We have tried using good quality fuel (the previous owner always used supermarket fuel) and this has made a bit of a difference - but it still does it. This weekend I will reset the ECU to see if that helps.

I would appreciate if someone could offer any other ideas as the only other alternative would be to take it to Vauxhall.

Cheers,

[Ste]

If it is advancing too much when under hard load, and all the position sensors and pressure sensors and MAF sensor and temperature sensors and O2 sensor(s) are working fine, then the only other thing is the fuelling and timing map is inaccurate. If this was the case EVERY Astra with the same mapping would have the same problem.

Quick questions would be how do you know it is pinking on clutch depression after 'lifting off' or 'planting down' the accelerator? What are the symptoms?

How old is the car, and when was the timing belt and tensioner done?

[spatch]

Thanks for the response

If it is advancing too much when under hard load, and all the position sensors and pressure sensors and MAF sensor and temperature sensors and O2 sensor(s) are working fine, then the only other thing is the fuelling and timing map is inaccurate. If this was the case EVERY Astra with the same mapping would have the same problem.

We are not seeing any fault codes so I assume the other sensors are working OK, and I would agree with you regarding the fueling/mapping on all Astras so I do not think it can be that.

Quick questions would be how do you know it is pinking on clutch depression after 'lifting off' or 'planting down' the accelerator? What are the symptoms?

With the windows open you can hear it. It only does it as the clutch is engaged and the engine is being loaded again after a gear change. At no other time is it pinking.

How old is the car, and when was the timing belt and tensioner done?

The car is an 03 with about 40,000 miles. It has full service history. I am not sure of the timing belt change intervals but I would not think it would be due yet. I would have to check the service book though.

Interstingly, the previous owner (her father) said it used to do it for him as well? I want to get it fixed as I do not like the idea of any pre-ingnition, even if only transient as the clutch is engaged.

[Ste]

When precisely is it doing it, as I cannot decide the exact time it does it.

So you are changing up gear, the full process would be, you declutch (and lift off acc), select gear, start to re-engage clutch and start pressing acc, clutch engaging and clutch pedal mid lift and acc pedal moving more on, clutch now fully engaged and acc on steady throttle.

When exactly does it do it????


Sorry for being really anal about it, but there's actually quite a lot going during a gearchange.

Does it do it if you lift off acc, then re-apply it without changing gear?

[spatch]

When precisely is it doing it, as I cannot decide the exact time it does it.

So you are changing up gear, the full process would be, you declutch (and lift off acc), select gear, start to re-engage clutch and start pressing acc, clutch engaging and clutch pedal mid lift and acc pedal moving more on, clutch now fully engaged and acc on steady throttle.

When exactly does it do it????


Sorry for being really anal about it, but there's actually quite a lot going during a gearchange.

Does it do it if you lift off acc, then re-apply it without changing gear?

OK, no probs. It happens after you have changed the gear and are in the process of engaging the clutch again and pressing the throttle to take up drive again. It generally stops when the clutch is fully engaged again. If you engage the clutch very slowly or are very gentle with the throttle it does not do it. However, during a normal speed gearchange it does. We have also noticed that it seems to be worse with this warmer weather but that could be that we have just had the windows down more.

From memory it does not do it if you floor the throttle whilst in gear (from off-throttle to full-throttle). However, I would not bet my life on this so I would need to check.

Cheers,

[macdad]

Pinking ..now then before the days of ecu and fuel inj etc..with the old carbs pinking was caused by too lean a mixture/timing etc...check the plugs bud..if very light brown in colour tihs will confirm..if so can be a prob with ems.

[spatch]

From memory it does not do it if you floor the throttle whilst in gear (from off-throttle to full-throttle). However, I would not bet my life on this so I would need to check.

Just spoken to wife and yes it does pink when in gear and you put your foot down - but just for a split second. It certainly does not pink for extended periods like olds cars used to (for example going up a hill). It is only transient.

To me it sounds as if it is over advancing itself momentarily - but why???

[spatch]

Pinking ..now then before the days of ecu and fuel inj etc..with the old carbs pinking was caused by too lean a mixture/timing etc...check the plugs bud..if very light brown in colour tihs will confirm..if so can be a prob with ems.

Indeed but would this not be picked up by the exhaust sensor - i.e running too lean? The fact that it is only transient would make me think it was a momentary timing issue. However, with the EMS I cannot see how a timing problem could occur either?????

I will try to whip a plug out to see anyway.

[Ste]

It sounds like a momentary low fuel injection, then the O2 sensor is detecting high O2 content, so the fuel trim compensates by increasing fuelling.

I would check for fuel rail for leaks or whatever, and electrical connectors to plugs. Then stick some injector cleaner in the fuel.
I wonder what the fuel pressure sensor is doing too, maybe reading slightly low but still within range???


At the end of the day, deciding how much / what to do depends on how annoying it is...

[spatch]

It sounds like a momentary low fuel injection, then the O2 sensor is detecting high O2 content, so the fuel trim compensates by increasing fuelling.

I would check for fuel rail for leaks or whatever, and electrical connectors to plugs. Then stick some injector cleaner in the fuel.
I wonder what the fuel pressure sensor is doing too, maybe reading slightly low but still within range???


At the end of the day, deciding how much / what to do depends on how annoying it is...

I cant say that I have ever smelled fuel so I would doubt there would be a leak, however, injector cleaner is a good idea since the car has been run on cheapo supermarket fuel most of its life.

I also think there would be some mileage in resetting the ECU, especially now we are only running it on 'proper' fuel. Nothing to loose.

If that does not fix it then I guess it would need to be plugged into a tech2??

Cheers,