I`m running an Astra G 1.6 8v hatch for about 8 months now, the mileage is approx 50,000 miles, the car has been serviced 8 months ago. All ok with the car up to about one month ago, then the car started to act up as follows.After a couple of miles driving, while braking for a roundabout / traffic lights etc., the engine revs drop down to zero on the rev counter and the engine stalls. After restarting the engine (sometimes with a bit of difficulty) the car then seems to kangaroo for a while then it clears up and continues as normal. If you then take the car onto the motorway and run it up to the speed limit, it runs well with no apparent problems. As soon as you get back onto the slower "A" roads and you have to brake the kangrooing returns and the engine again wants to stall.The engine always starts first time in the morning, it idles smoothly at 800 / 850 rpm. I have been told it might be a problem with the petrol pump or petrol filter. Have any of you Astra G boffins out there had similar problems like these. If so I would be grateful for your thoughts and possible actions on the symptoms.
Edited by Dynamic Dave on 25/03/2008 at 00:28
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As a quick, cheap, temporary diagnostic step, try blocking the EGR off.
Another thing that's worth doing is making sure the ECU software is the latest version - the latest software includes some drivability enhancements - not least, including disabling the EGR. The software update is a dealer only job - at which point, they will also see any stored fault codes.
Edited by Dynamic Dave on 25/03/2008 at 00:29
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Thanks alot for your reply its very helpful. But as I have only basic car mechanical skills, can you discribe what an EGR is, what it does, where in the engine will I find it, and once identified, what I can use to block it off.
When I know all these things I will give it a go. If after the car is no better, I will book it in at my local dealer to have them check out the ECU ( ENGINE CONTROL UNIT) software etc. Oh by the way where is that located also. Thanks once again.
Cheers Torribaz.(Costa Blanca).
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The EGR valve is at the back of the engine, and looks a bit like a small can, standing vertically. It's held on by bolts at the base, and it's fairly obvious how to make up a thin sheet metal gasket to temporarily block it off - just as a test.
The EGR allows some exhaust gas back into the inlet under certain engine operating conditions. By diluting the air, it lowers peak combustion temperatures, and so reduces the formation of the various oxides of Nitrogen which are called NOx.
These valves typically fail in the partially open position, and allow exhaust gases into the inlet when the engine can't deal with them, particularly at low engine speeds, and low throttle openings - hence the suggestion to temporarily block it off.
The ECU software is accessed via the diagnostic connector - but, you won't be doing this yourself, so don't worry too much about it. I recomend that you get the software updated whatever you do - it really transforms the feel of the car, and shouldn't be too expensive.
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Hi Number Cruncher,
Thanks for your prompt reply and detailed info. I will look at this in the morning.
Cheers Torribaz.
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the software up date tells the ecu that it do's not have an egr valve if the old egr valve is within range then a blanking gasket is fitted and the old egr is refitted if out off range then a new one needs fitting and software updated accordingly
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sorry forget to mention that if its an auto then you cant blank the egr and tell the ecu that it has not get one
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The way it was explained to me was;
- if the EGR valve is found to be fully closed, then all is well, and just the software update is applied, and the EGR never opens again
- if the EGR valve is found to be stuck open, and cannot be closed, then a new one is fitted, and then promptly disabled via the software update
Having said this, depending upon which version of the software is currently in the ECU, there were updates before the one where the EGR function was [finally!] disabled which improved driveability - I *think* the drive by wire control laws were updated. i.e., it's still worth doing the software update even if you blank off the EGR.
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