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Discussion Starter #1
Hi, I have a Corsa C that just stopped working without warning. I have put in new Spark Plugs, Air Filter and cleaned the throttle housing. It will start for 10 seconds if I use spray easy start thus the Spark Plugs fire. I have looked at the Fuel rail and pressed the depressurise valve and petrol comes out with force.

There are no fault codes when I do the Pedal Test. I was thinking it might be the MAP sensor and the inlet air temperature sensor. I was wondering if it was an Imobaliser problem.

Thanks
richard.
 

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What engine is it. Does the spanner light flash when you turn it on.
 
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Discussion Starter #3
It is a corsa 1.2 sxi.

I have put new spark plugs in, a new air filter and cleaned the throttle body.

When I switch it on the emmitions light and spanner light come on but the spanner light goes out and then the emmitions light goes out. I did a peddle test and there are no fault codes.

I have sprayed easy start into the throttle body and have started it that way but when I did this today it did try to fire but did not start. I think the plugs are sparking. The fuel rail has fuel in it and when I press the valve petrol spurts out. When I switch the ignition switch to on ie position 2 the EC relay is on but not the fuel relay (I was told that the fuel relay should be on in this position). The puel relay does come on when I crank.

It it sparks Does that mean that Crankshaft sensor is OK. I keep thinking its the immobiliser but the spanner light does not flash.
 

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Turn it over and look at rpm needle. If it hovers around 200rpm it's fine. If it's on zero or erratic its probably faulty.
 
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Discussion Starter #5
Turn it over and look at rpm needle. If it hovers around 200rpm it's fine. If it's on zero or erratic its probably faulty.
I had looked at the rpm needle last week and that was ok.
I took the spark plugs out and they had lots of fuel on them. I then fired them to make sure they fired and they did. The crank sensor it ok.

I then checked the compression as i had a spark and fuel and it was 230,210, 250 and 250 PSI. The compression was is ok. My query is that my Haynes manual claims that you can't test the compression in the old way as there is no cable to hold the throttle valve open. The pressure went up for me ok but you can open the throttle and put something in it to keep it open to do the test. Surly you don't need to take it to Vauxhall just to find the compression.

thanks
 

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yep,pull out the fuel pump relay,second person to hold acc pedal to the floor
 
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Them compression results are fine. I've found opening the throttle plate makes very little difference anyway. So you got spark, I'd be looking a fuel pressure. I'm sure mine was around 58psi from memory.
 
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Yep, fuel pressure needs to be 4 bar or it wont start, buy a fuel pressure tester from ebay, they are cheap enough,
 

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Discussion Starter #9
I have measured the fuel pressure but when the ignition is switched on in position 2 there is no fuel pressure and I can't hear the fuel pump. When I crank the engine the pressure goes up to 48 psi and if i leave it it will slowly go down to 46 psi.
I watched a you tube vidio and the presures were the same as mine but the car was not a corsa. My engine does not run and so the results are different to a running engine. I think the pressure is ok but others on here say it must be 4 bar.

The other issue is the pump does not prime in position 2 but I have checked the circuit and the pump works when i crank the engine. The pump works when i short out the relay to the pump and then the pump sounds ok.
Thanks
Richard
 

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Its 10 psi lower than mine. Mine is 58 with ignition on and 60 with engine running. Not sure if 10psi difference would cause a none start to be honest. I'm thinking it should still start with 48psi. See what @andyl thinks
 

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I would of expected a lower reading if the pump had failed, when was the fuel filter last replaced.
 

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Discussion Starter #12
I replaced the fuel filter 18 mounths ago so I don't think it is that. The pressure holds when I switch the ignition off.
If I put the ignition on in position 2 then the pump does not prime but works when i crank the engine. The ecm does not pull the input of the relay down near 0v but it it at 3.5v so the relay cant switch. The relay has 8.5 volts across it (12 -3.5). Other people have had the same problem. I have looked at the earths but they look ok. The ecm could be playing up but it sparks and works the fuel pump when cranking.
 

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Are you sure the injectors are being triggered when cranking, if the pressure is sufficient it wont prime the system at every ignition cycle. Fit a noid light in one of the injector plugs then crank it and see if it lights up/flashes, if you dont have a noid light use a capless 501 with the pins straightened.
 

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Discussion Starter #14
I have put a capless 501 across the injector and it flashes when cranking. The voltage on the fuel relay relay side of the capless 501 is 11.3v and on the EMU side it is 10.1 volts DC. The multimeter is not fast enough to capture the voltage when it triggers and I assume this end goes from 12v to 0v when it triggers and I am measuring the average.

The car sparks and fires when I put easy start into manifold. The fuel pressure is 48 PSI (I did read that this is OK but dont know for sure). There are no fault codes. The battary voltage is 12.95v. The coolent temperature read 2.5k when cold and my code reader read that the engine temperatute is 23 degrees which is ok.

The car started and just stopped about six weeks ago

Thanks
 

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I would try a new fuel pump, the pressure should be 4 Bar, idf its not at that pressure and wont maintain that pressure while cranking then you would have to assume its faulty, if it runs on easy start then its definitely fuel related.
 

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Discussion Starter #16
Thanks, Haynes manual tells me to syphon the petrol out the tank to change the fuel pump but they don't do that on You tube. It it too dangerous to do the job without emptying the petrol tank.
 

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An empty tank is more dangerous because of the petrol vapour that builds up inside.
 

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S
I have put a capless 501 across the injector and it flashes when cranking. The voltage on the fuel relay relay side of the capless 501 is 11.3v and on the EMU side it is 10.1 volts DC. The multimeter is not fast enough to capture the voltage when it triggers and I assume this end goes from 12v to 0v when it triggers and I am measuring the average.

The car sparks and fires when I put easy start into manifold. The fuel pressure is 48 PSI (I did read that this is OK but dont know for sure). There are no fault codes. The battary voltage is 12.95v. The coolent temperature read 2.5k when cold and my code reader read that the engine temperatute is 23 degrees which is ok.

The car started and just stopped about six weeks ago

Thanks
Thanks, Haynes manual tells me to syphon the petrol out the tank to change the fuel pump but they don't do that on You tube. It it too dangerous to do the job without emptying the petrol tank.
 

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If you want to be really safe drain the tank.
Take it outside and fill it with water.
No chance of exploding then.

Problem is you have to wash it out with methylated spirits to soak up all the water then dry it thoroughly before refitting it.
 
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