C5 Tank Lift Pump Wiring

[GaryM]

I have a 2006 2.2 auto diesel exclusive. It has been cutting out whilst driving, the last time was last week, coming down the M1 from Dublin in rush hour traffic and doing a normal 120 in the outside lane. We made onto the shoulder through three lanes of traffic and got home without any more trouble. The next morning it wouldn't start, the engine turns over but doesn't seem to be getting diesel. I took off the cover of the lift pump and disconnected the outlet pipe of the pump and turned the engine over but didn't see any fuel coming out. I want to try the pump on it's own to see if it's working. Would anyone know which of the terminals in the connector on the pump top I should connect an electrcal feed to. Would the brown wire be the positive & the green the negative?

 

[Randombloke]

Any lights on the dash? Error messages?

 

Usually with Bosch fuel injection there is a low pressure code which will trigger the MIL on the dash.

 

Cutting out and dying are often caused by the crank position sensor.

 

You will usually get a code for this too.

 

I'd check the cables to the crank position sensor and and the camshaft position sensor are in place first and not loose.

 

Could also be a loose fuse in any of the fuse boxes, or an intermittent cable connection. 

[GaryM]

Thanks. No, the dash is all clear before this happens and then there's the usual Depollution System Faulty & Engine Management System Faulty messages which persist until the car has been restarted five times. Engine starts after about thirty seconds after the initial cut out.

[paul.h]

You should use a code reader to see what fault is causing the depollution system and engine management system messages/lights. This could well point to your running/not starting problem. These messages mean there is a fault that affects the running of the engine and can affect the exhaust emissions. Possibilities include a cam or crankshaft sensor, the MAF, a lambda sensor, the DPF, the catalyst, etc. Just trying to replace a part without the check could result in replacing lots of unnecessary parts until you find the one at fault.

 

If for example the crankshaft sensor is faulty, it may prevent the fuel pump running since the engine management system is not seeing the engine turning over.

[GaryM]

Hi Randombloke & paul.h. I do agree 100% that  replacing lots of unnecessary parts until I find the one at fault is not the way to go. What I'm up to at the moment is trying to rule out all the major components. I connected a feed to the terminals on the lift pump and the car started and continued to run until the feed was disconnected. So I'm deducing that there's not much wrong with the fuel supply to the engine that the lift and high pressure pumps are ok and that the fuel filter is ok (it was replaced last week). I'll go on from there and see if there are any wiring breaks / loose connections. There doesn't seem to be a supply going to the lift pump via the loom for example. I fully take on board your advice about the diagnostics though. Thanks.

[coastline taxis]

Hi  in the engine fuse box with the key out. 3 big multiplugs pull out the middle one (slide the clip backover) now look at the left hand side of the multiplug 3rd or 4th wire down and check to see if its burnt out also check the corosponding pin on the fuse box