Astra coupe 1.8 - Astra Coupe 1.8 rough idle, video in thread

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Wed 8 Jun 2011 17:15
Astra coupe 1.8 - Astra Coupe 1.8 rough idle, video in thread - shorty87

Hiya, I recently picked up this Astra, a 1.8 coupe, its got good service history showing a recent engine overhaul and cambelt but its doing this:

[YOUTUBE]98RkaXaxEHo[/YOUTUBE]

www.youtube.com/watch?v=98RkaXaxEHo

does anyone have any ideas? I've searched on here and was thinking of cleaning the carb and throttle body, then checking the egr, afm etc would that sound the right route?

Cheers Ellie

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Wed 8 Jun 2011 18:13
Astra coupe 1.8 - Astra Coupe 1.8 rough idle, video in thread - injection doc

the way the engine is hunting would sugest an air leak, this will make the engine idle up and down.

2nd if the throttle body setting has been altered or the throttle body idle switch is set an at incorrect voltage this would alos make it hunt at idle as the engine wouldnt know what it was meant to be doing.

i aslo suspect that the K&N air filter is not helping the situation and may well of contaminated the air flow sensor !

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Wed 8 Jun 2011 18:28
Astra coupe 1.8 - Astra Coupe 1.8 rough idle, video in thread - shorty87

Thanks for your reply, how would i go about setting the throttle body? I;ve got it cleaned up as it was quite dirty.

The K&N filter came fitted on the car, hopefully its not done too much!!!

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Wed 8 Jun 2011 19:18
Astra coupe 1.8 - Astra Coupe 1.8 rough idle, video in thread - doofer

Going by the state of that air filter I'd be dubious about the 'good service history'.

The engine has 'Mk 4 astra' painted across the front, which would suggest to me it's a replacement engine, does the history refer to the new engine or the old?

I'd be worried about the quality of the work, the MAF sensor does not appear to be connected, so who knows what else has been messed about with.

What year is the car?

Edited by doofer on 08/06/2011 at 19:22

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Wed 8 Jun 2011 20:18
Astra coupe 1.8 - Astra Coupe 1.8 rough idle, video in thread - track

the engine doesnt say mk4 astra the coil pack does. Would be a common thing for the coil to of been replaced by now. The air flow sensor doesnt affect idle on this model so rulke that out. It sounds like an air leak. Spray some carb cleaner around the intake system components nd see if any points make the engine note change. That will indiciate the source of the air leak. Once you cure the idle you need to stick a standard airbox on and plug in the air flow meter. If it drives poorly with the air flow meter on then its faulty and they have unplugged it to keep it running.

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Wed 8 Jun 2011 20:36
Astra coupe 1.8 - Astra Coupe 1.8 rough idle, video in thread - unthrottled

cleaning the carb and throttle body,

Good luck finding the carb on a fuel injected engine. The hot air intake isn't doing it any favours either.

Edited by unthrottled on 08/06/2011 at 20:44

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Thu 9 Jun 2011 01:12
Astra coupe 1.8 - Astra Coupe 1.8 rough idle, video in thread - shorty87

The service history shows an engine overhaul in 2009, its a 2000 plate car.

I'm waiting on a standard air filter and housing etc to arrive and that other filters coming straight off, didn't like the look of it from the start!

I noticed the sensor was unplugged just after filming this, plugged it back in but didn't make much difference :( Hoping putting the standard air filter etc on will help!

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Thu 9 Jun 2011 02:13
Astra coupe 1.8 - Astra Coupe 1.8 rough idle, video in thread - unthrottled

It won't help the hunting but it might be useful to keep intake temperatures down.

Is the 'overhaul' itemised? ie what was done. I suspect the MAF is dirty-you need the MAF working to get cat to work properly and get it through the mot test. What's the economy like?

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Fri 10 Jun 2011 01:40
Astra coupe 1.8 - Astra Coupe 1.8 rough idle, video in thread - shorty87
I'm not too sure on economy, i took it in as p/ex, its un-mot'd so not driven it since!
Ive changed the MAF and its running far better, just need the arbox now, are they the same for the coupe versions as the regular astras?
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