Replacing The ECU

[zakmuh]

Hi

I have starting issue with my 2007 XC90 D5. Done all the checks and its the HP fuel pump that is not sending any drop of fuel to common rail. This is because the low pressure pump in the tank cuts off as soon as key is turned to starting position III (with ignition on II, fuel would continue to flow like 2 litres per minute)

I suspect there is an issue with the ECU. Is replacing one from eBa as straight forward as I think or would I have to take it to Volvo and what needs doing?

Thank you

[Clan]

Originally Posted by zakmuh

Hi

I have starting issue with my 2007 XC90 D5. Done all the checks and its the HP fuel pump that is not sending any drop of fuel to common rail. This is because the low pressure pump in the tank cuts off as soon as key is turned to starting position III (with ignition on II, fuel would continue to flow like 2 litres per minute)

I suspect there is an issue with the ECU. Is replacing one from eBa as straight forward as I think or would I have to take it to Volvo and what needs doing?

Thank you

The ECU is always the very last thing you change and then only when you have PROVED that it is faulty . It is highly unlikely to be the ECU in a volvo . The in tank pump should run for about 20 seconds when you turn the ignition on then it will turn off ... and at all times it will run when the engine is running.

Are you sure the fuel isn't simply running straight through one or more faulty injectors and back to the tank?

The ECU contains security and if faulty will need a new one and its unique software from volvo . There may repair businesses around which could repair yours .

[zakmuh]

Hi Clan

Thank you for your reply. I checked everything one by one and I doubted it would be the ECU as its cutting the low pressure pump when cranking. Until I crank, the pump would flow fuel and I could empty the entire tank

Anyways, I found when cranking rpm wouldn't not work at all. It it'd be the crank sensor either faulty or snapped a wired when I was removing the EGR system. I'll check today and report back

Cheers

[zakmuh]

Hi,

Sorry this is the first time I'm checking ohms reading, so multimeter gives 0.13 ohms @20k setting, 122 @2000 and 122.8 @200

Is the crank sensor good or bad and what reading an intact should read?

And also try to check the response from scanner and doesn't look like sensor getting any readings from flywheel teeth?


rpm.jpg

[reggit]

I’ve had a quick dig around the forum and the 122 ohm figure comes up a few times so I’d be guessing it’s correct.

NB always take resistance readings on the lowest scale setting you can for most accuracy.

I’d suggest you get it on Vida for fault finding as that will guide you through tests.

[zakmuh]

Thank you for reply reggit and noted on the multimeter setting.

I have VIDA software but dont have DICE. I do have Delphi Scanner with a laptop. Would this help to trace the fault?

[zakmuh]

I'll rule out the ECU and do further checks

Thank you

[zakmuh]

Still no joy

[reggit]

Have you tried blowing a little easy start up the inlet and see if it fires up on that? (It’ll run rough as anything on that stuff if it fires it)

I remember my dad having a no start problem on his euro4 xc70. Seem to think it was the EGR valve that had failed (may be wrong on the cause, it’s a long time ago)

[zakmuh]

Hi and sorry for the late reply

Car is now sorted. The issue I had was...I had not done the priming correctly, therefore there were lots of air in the fuel line. I did the key On and OFF cycle for over 20 times (as advised by Volvo) and then car started straight away.

If you remove any fuel system line (like a hose or a banjo bolt or high pressure pipe etc), it sucks air in then stops sending fuel to common rail. When you turn the key to ON (ignition on) and if you have air then you could hear fuel flowing in there inside the fuel filter housing under rear passenger seating location. So you have to prime until you hear nothing but whining noise. This is achieved by above method, ON and then OFF

Cheers