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Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 21609
Experience:  BEng hons Mech engineering, in auto industry 22 years
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I have a 2002 Vauxhall/opel Astra 1600 CDE ( ecotec engine)

Resolved Question:

I have a 2002 Vauxhall/opel Astra 1600 CDE ( ecotec engine) for about 12 months now I have had a problem, the car starts with one turn in the morning, it has full power and is fine for about 1 km after pull off, it then begins to lose power and cuts out when you stop. After waiting 30 sec or so it starts again, this process repeats about 4 times or so then it is ok for the rest of the day and power returns. The problem happens more frequently in the winter or cold weather. The service centre that has the car has done the following. a) replaced the oil pump which made the problem worse ( increased oil pressure), b) changed the valve lifters, c) done a fuel pump test,d) tested the coil pack, e) Tested the lamba sensor. F) the oil was changed in case it was an oil viscosity problem. There is no cat converter on this model in South Africa, They have now removed the head of the engine in a hope that the problem is there I am doubtful, GM South Africa are a complete waste of time and wont even take the call. My concern is that the issue seems to be more prevalent during cold or bad weather, the summer months the problem hardly appeared only on odd occasions. This tells me its temperature related some how. The car had a complete engine rebuild at 305000km and is now on 380 000km. I am desperate to get this sorted out... regards
Submitted: 1 year ago.
Category: Car
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Expert:  Matt replied 1 year ago.


This sounds like an electrical actuator or sensor at fault .Usually when you can cycle the ignition key on / off and then restart the engine and the fault is gone temporarily this indicates that this is an electrical component causing this issue.

This could be a wiring issue as things tend to expand when hot and its possible a poor or partial electrical connection is being pushed apart on one of the major sensors so check the connection plug and wiring to the following;

Airflow meter

Crank position sensor

Cam position sensor

O2 sensor

Throttle position sensor

unplug each in turn and use some switch / contact cleaner spray on the pins to ensure its all grease / dirt free

Also worth checking the connections to the fuel pump for the same reason - unplug each in turn and give them a good squirt of switch / contact cleaner - Not WD40

and also unplug and inspect the main power relays and fuses for signs of overheating or corroded terminals - so the ones for the ECU and the fuel pump

And also unplug the wiring loom connections in the engine bay one at time and inspect for corroded or recessed pins.

Check the resistance of the spark plug leads ( 13-15Kohm / metre) and replace if any doubt or high resistance - Also replace the spark plugs if any of them fail this checklist:

Also its worth checking that the electric pump that feeds the injectors is working correctly, it should run for a few seconds then switch off when you first turn the ignition on. If the connections to this are corroded or damaged then the pump could stop at any time. Check that its relay switches in and out and the relay contacts are clean and bright – replace the relay if in any doubt and do the same for the fuse, ideally measure the voltage at the pump and check its getting 12V

Also check for exhaust leaks before the o2 sensor as if this has been experiencing an exhaust leak then it will have been running very rich as the sensor will see the extra air pulled in as fresh / lean fuelling and be adding fuel to compensate.

this can lead to catalyst failure as the extra fuel can re-light inside and melt the catalyst

The best way to find an exhaust leak is to run the engine from cold and feel around the exhaust joints with your bare hands - you'll have about 30 seconds before it all gets too hot and you should feel any escaping gas blowing over your fingers

Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 21609
Experience: BEng hons Mech engineering, in auto industry 22 years
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Customer: replied 1 year ago.
Thank you for the information i have sent this on to the work shop that have the car. My concern is that they have now taken off the head and sent it away for checking as they are convinced its a valve problem. I do not share this belief. If it was a problem with valves the loss of compression would be permanent.

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