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Discussion Starter #1
My Mum has a 2008 Mercedes A170 (W169) automatic with about 140 000km on the clock. In the morning it struggles to start. It'll crank a number of times and not fire at all. Eventually it'll fire and then immediately die for a few more cycles before eventually starting and running as normal for the rest of the day. Once it eventually starts there are no warning lights or error messages on the dashboard display

The local indie has read the codes and found no errors. He hasn't had the car when the actual fault manifests itself. He seems to think it could be the ignition switch but I have my doubts. His thinking is based on the fact that it if you turn the key it'll crank the starter even if you let the key go. Effectively you can turn the key, walk away from the car and it'll continue to crank for about 20 seconds before either shutting off the starter or firing. My thinking is that this is normal behaviour as most modern cars have a computer controlled starting cycle that'll crank the starter until the engine fires. This is to stop people cranking the starter while the engine is running. It shuts the starter off after 20 seconds of cranking to protect the starter itself in the event that the engine doesn't fire.

From what i can find rooting around on Google it's more likely either a fuel pump relay problem or the fuel pump itself. Any thoughts would be welcome??
 

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Well, you don't say for how long this goes on, but it might be worth a try to test the battery.
It is after all battery season now...
 

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Discussion Starter #3
It doesn't behave like a battery problem. The car cranks very vigorously and all electrics behave as they should.

It's always the first start of the day. It normally takes 8-10 turns of the key to get it going.
Of those 8-10 turns it behaves as follows:
turn 4-5: cranks and does not fire at all
turn 6-8: cranks and fires but immediately dies
turn 8-10: the car cranks, fires and runs as normal

Once the car has started it runs totally as normal. You can also switch off and restart as many times as you want and it behaves as normal. you can shift from Park to Drive or any other gear and it runs/idles as normal.
 

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Something in the cylinders that builds up overnight? Which is then cleared from the engine after a few cranks.

Fuel leak from the injectors? Gasket problem?
 

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I understand, but from the googling I did on the issue, a few guys tested and just replaced the battery have it tested. In CT the tests are free. Should be the same in JHB. Other thing is, it is the cheapest thing to rule out.
Next thing is a possible head gasket that leaks water into the cylinder head and prevents start up, but I'm doubting that as you would have fluid loss.
I maintain to check the battery first.
 

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Discussion Starter #6
Well I thought i'd get some starting fluid and next time it refuses to start I can squirt some into the inlet and see if it makes any difference.
 
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