Boxer II Runs on 3 cylinder fault code P0303

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Orchid70
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Boxer II Runs on 3 cylinder fault code P0303

Post by Orchid70 »

Hello
Im struggling.
I have fault code P0303 - Injector number 3 stuck closed
I have read with Autocom and SnapOn. Same fault code.
I did change the injector, with a used one.
Same fault code still.
The cylinder 3 does not fire at all. I can pull the connector to the injector and nothing happens. Pulling the rest of the connectors - will kill the engine.
I have checked the injectors with oscilloscope (SnapOn). And alla injectors give the same pattern.
I have also checked the wiring between ECU and injectors - all OK!
Any ideas?
Is it time to buy Lexia? We have bought our selves a 2011 C5 with problems with gear change, so would be good to have it.

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Paul-R
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Re: Boxer II Runs on 3 cylinder fault code P0303

Post by Paul-R »

Which end of the engine did you count from? PSA engines count from the gearbox end so if you counted from the auxiliary belt end you will have changed the wrong one!

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xantia_v6
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Re: Boxer II Runs on 3 cylinder fault code P0303

Post by xantia_v6 »

I think that P0303 is detected by the engine ECU monitoring the crank position sensor and determining that cylinder 3 is producing no power.

On a Diesel, this could be lack of fuel, or it could be a lack of compression. Are you able to perform a compression test? or even crank the engine with the injectors disconnected and listen for even cranking on all 4 cylinders?

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Orchid70
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Re: Boxer II Runs on 3 cylinder fault code P0303

Post by Orchid70 »

Thank you
I do know that the cylinders are counted from the flywheel on PSA - but see this video:


I do not have copression tester for Diesel. So will have to try to figure it out without one.
Will get back on that later.

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xantia_v6
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Re: Boxer II Runs on 3 cylinder fault code P0303

Post by xantia_v6 »

Maybe you can use your oscilloscope to monitor the battery voltage when cranking, the dip in voltage as each cylinder hits compression should be equal.

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Orchid70
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Re: Boxer II Runs on 3 cylinder fault code P0303

Post by Orchid70 »

Thank you Xantia_v6!
I have ordered Lexia 3 from UK today and its already left to the Post Office!! Im going to need it for the gear change problems on our new C5.... but thats an other story.
Thats a very nice tip! Im not too familiar with the oscilloscope - learning =)
I took a footage of cranking the engine - guess I dont even need the oscilloscope (God only knows, why we didnt think of doing this before..... hubby is the old time mechanic and Im learning....):

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xantia_v6
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Re: Boxer II Runs on 3 cylinder fault code P0303

Post by xantia_v6 »

That cranking sounds a bit lumpy.

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Orchid70
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Re: Boxer II Runs on 3 cylinder fault code P0303

Post by Orchid70 »

Found the firing order in my old Autodata:
Boxer firing order.jpg