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Car start problem/ ignition sequence query

Hi there,

Recently I've had trouble starting my car. Not every time, though, and not predictably. When it starts it starts fine, at other times it cranks well but doesn't catch.

Eventually, after much cranking and re-charging of the battery it will catch (usually when I'm stamping on the throttle as well - maybe a connection?). Just before it catches I hear the fuel pump relay engage.

That made me think that it wasn't getting fuel. I bypassed the pump relay and manually turned the fuel pump on but still it didn't catch - there's plenty of pressure in the fuel rail.

That meant to me that either the injectors weren't working or there wasn't a spark. It's hard to check for sparks in mine because there's no HT leads that you can get at easily - The whole DIS module is stuck in between the two cams (it's a 1.0L 2000 Vauxhall Corsa btw).

My questions are firstly: why doesn't it start? :-) and secondly: does anyone know the exact order of events during the ignition sequence?

The reason that I ask this is that I suspected the fuel pump but bypassing the relay didn't help. Despite this, when it does catch, I hear the relay click just before ignition. What else is the ECU doing at this point? Is the PIP signal likely to be a problem and can I check things like that without an oscilloscope?

Any help is much appreciated,

James

Reply to
James Larkin
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Crank angle sensor. Everytime, 100%.

Reply to
Sandy Nuts

You reckon?

Is there any way to check the functioning of the sensor without replacing it? I've had the plug out and looked at it but there doesn't appear to be any corrosion etc. The wiring between the sensor and the ECU is a right pain to get to. I may have to put in a little more effort :-)

Thanks for that,

James

Reply to
James Larkin

You might try making up a plug in lead with a spark gap....

Short bit of HT cable fitted with a plug one end socket the other, cut it in the middle and push a pin into the core. Rejoin the cut ends with a small piece of clear tube such that there is a small gap between the pins to create a spark gap.

If you can't see the spark, you should be able to hear it load and clear on the radio :-)

Reply to
Harry Bloomfield

For those who are interested, I've checked the lead and the connector for the crank sensor and not found a problem. I've sprayed the whole shebang with WD40 and put it back together. It started first time (as is usual) and has started every time since. If it plays up again, I'll think about changing the sensor.

Until then, fingers crossed.

James

Reply to
James Larkin

They usually fail internally - often where the cable is connected to the coils, etc.

Reply to
Dave Plowman (News)

Does the engine warning lamp go out?

If you read the diagnostic codes after it has failed to start it should indicate the fault - most likely a sensor. Could also be the coolant sensor (temp v.high).

A good garage (if you know one) will be able to diagnose the problem very quickly, maybe cost you £20. But look on the web for DIY methods, e.g.

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Jerry

Reply to
PSOE

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