Xsara Picasso 1.6 Petrol - Fuel pump not running

[rubber_hammer]

Hi everyone

I've been struggling with an intermittent problem on my 2007 Citroen Xsara Picasso 1.6 petrol for some time now. When the issue occurs, the fuel pump does not prime up upon turning the ignition on. The pump is working when wired to the battery. I also have a second pump as a spare, which works off the battery, but not when connected to the car's connector block.

My multimeter is reading 12v across the terminals when the ignition is initially turned on - 7v when the ignition is off or times out.

I've tried a spare relay in it too, which is from a donor car.

When I remove the fuel pump fuse, I get a constant 12v reading across the connector block terminals, so am not sure why that is. I'm guessing it cuts out whatever is regulating the voltage.

I'm clutching at straws a little now, but if anyone can suggest any obvious things to check, it would be a big help. Some explanation of how it all fits together and prerequisites needed for the fuel pump motor to activate would be really helpful too. Also, a wiring diagram that covers the circuits involved would be a bonus. I've got the online Haynes Manual and also their diagnostics manual and neither really give me anything to grip on to - or at least I'm not grasping anything obvious.

Just some other history - when I read the OBD codes previously, it flagged up the crank position sensor, so I changed that - but it didn't resolve anything. The same code has shown again this time, but I'm not convinced it's relevant? I'm also wondering if the fuel pressure sensor is involved in any way - I believe it's integrated with the fuel rail...could it need to read the fuel pressure before the ECU tells the fuel pump to activate? Like I say - clutching at straws a little.

Many thanks for your time!

Shane

[GiveMeABreak]

In case it's relevant, just beware of cheap replacement sensors - we've lost count of the number of people that have bought cheap sensors only for them to be dead on arrival - especially from ECP... Always get good quality branded sensors, especially if you have replaced it already and still get the same relevant code.

[rubber_hammer]

Thanks Marc - good point. I did buy the sensor from ECP.

[wheeler]

There is no fuel pressure sensor on this engine.
You say you changed the fuel pump relay? Which relay was this as on your car the fuel pump relay is integrated into the under bonnet fusebox & not replaceabe (not without opening the fusebox & soldering anyway.
The crank sensor does have a part to play in fuel pump operation if the engine turning signal stops it stops powe to the fuel pump however i would still expect it to initially prime.
As for checking the power supply to the fuel pump, a volt meter alone is not enough, check it with a bulb (not an LED) across the supply & earth, you can get 12v on your meter but there is not enough current to power anything. This is actually a known issue on the older Xsara, fuel pump does not run 12v at pump connection. Caused by a high resistance in one of the main loom connections.

[rubber_hammer]

Hi Wheeler, thanks so much for your reply. By fuel pump relay, I mean the double relay shown below, which is attached the the outside of the plastic fuse box casing under the bonnet.

Yes, I understand your point about the multimeter voltage reading. I have run a known working bulb across the supply & earth and it doesn't work, which I guess indicates an issue with the supply of current. Working out where is the issue, as I'm struggling to work out which wires are involved.

Thanks again. If you have any further thoughts or comments, they'd be much appreciated.

[rubber_hammer]

Hi Wheeler, having read up a little more, I can see there are some individual relays inside the fuse box, whilst the one I posted a pic of is the double ECM relay.

[wheeler]

Can you confirm the year of this car? your original post says its a 2007 which means there should not be any replaceable relays in the under bonnet fuse box & no separate fuel pump relay. Better still post up your VIN (which will be auto masked from public view) & this means we can get a proper wiring diagram for it too.
The separate double fuel pump relay disappeared from the xsara picasso around 2002.

[rubber_hammer]

Hi Wheeler, thanks for your help. The VIN is VF7**************[VIN obfuscated, can be read by forum staff]. I may be referring to it as a 'double relay' in error or out of proper context, but please see pic of it in situ below. Yes, it's definitely a 2007 model.

Thanks again!

[wheeler]

So yes you have the later style fusebox with no replaceable relays. I'm not sure what that double relay is for on your car, If it were a C4 i would say it is the ABS system relay but just checked the ABS diagram for this car & it doesent have a relay in it.
The feed to the fuel pump comes from the internal relay in the fusebox from pin 11 of the 16 way grey connector

[rubber_hammer]

Thanks Wheeler. I had a quick look at that connector block... Pin 11, as long a I've got it correct (top row of the block, 3rd in from the right), isn't giving a voltage reading - but the supply to the pump does have a voltage. That said, some of the pins in the block do look like they need a bit of a clean, so I have ordered contact cleaner. The black connector block has numerous wires that give a voltage reading that corresponds with what I'm getting from the fuse and the supply wire at the pump (e.g. 7v when the ignition times out), if that counts for anything.

Another option I am likely to try is - I'm friendly with the owner of a local breaker yard; he let me borrow the other pump I have from a scrapped Xsara Picasso. I'm going to see if he'll let me have the BSM unit from the same car tomorrow. I think it's worth a punt. Would you tend to agree?

[wheeler]

Sorry, just noticed the wiring diagram has not attached to my previous post, i’ll try re adding it later.
My first thought as soon as i started reading your first post was BSM, if you can get hold of one then yes its definitely worth a punt.
The pin numbers should be marked on the connector, once i put the diagram up you can confirm by checking the wire number. Once confirmed if you back feed this wire at the BSM with 12v the fuel pump should run to confirm the wire is OK.

[wheeler]

Just updated the previous post with the fuel pump wiring diagram, the pump is component 1211, The wire number of the fuel pump feed is 1201 along its entire length, it comes from the under bonnet fuse box & then through the little 6 way connecter next to the fuel tank & straight to the pump from there, The wire colour will likely be pink/rose but this is not definite.
Im really curious as to what the double relay is for on this model, can you identify any of the codes printed on the wires? ideally the big thick yellow one.

[rubber_hammer]

Thanks Wheeler. I'll get back to you on some of your questions shortly.

Regarding the other BSM that I was going to try - it was the wrong unit/model, so I had to leave it. I see numerous listings on eBay for them - do you know if the ones advertised as being from a diesel car will work on a petrol one? They look identical and the model numbers are the same.

Many thanks again.

[wheeler]

Dosent matter if its off a diesel model. Most of the Xsara Picasso ones now all change onto the same part number now anyway.

[rubber_hammer]

Thanks Wheeler. I've ordered one now - from a Peugeot, but model number matches up. Fingers crossed.

One thing that's confusing me... pin 11 on the connector block is an orange wire and is printed with 1201 - but the supply going into the pump is pink. The orange wire is also not giving a voltage, but the wire to the pump is. From the ones on eBay, I noticed a number of different variations - most with a pink wire in pin 11, but a few with orange.

I'm not sure about that double relay. I took a few more pics of the wires going into the connector block if you want me to post it up. Just realised that you asked about the wire codes - I'll check them tomorrow after work and will post them up.