D4204T Injector Issues - 2008 S40 2.0d

[MSwift]

Hello - I have a 2008 S40 2.0d and a routine oil change in the week, has resulted in non-starting and has progressed to non-firing on 2 cylinders.

Oil and filter were changed, injectors unplugged to turn over several times to prime the oil system (the change was carried out by my brother who did not know this was not necessary when the oil filter is at the end of the oil cycle. Now suspect this returned fuel to tank and caused fuel pressure loss).

Injectors plugged back in and engine restarted. Engine was making rattling sounds so was switched off. The engine would not start again with each attempt after this. Enlisted the help of my Dad at this stage as he is much more experienced with engines than my brother and I.

The fuel system was manually primed using a hand pump to pull fuel through. After some time attempting to get it going again, it finally spluttered into life.

Due to the rattling sound and revs not exceeding 1100rpm even with the pedal to the floor, we inspected each injector and discovered two were not firing. Looking at the car from the front, left-right, these were injectors 1 & 3. Tried cleaning the contacts but didn't help.

Using a volt meter, discovered potential lack of electrical signal to the injectors. Inspecting the wires we found extremely minor wear on the wires so taped these up.

'Cracked' each injector to check for fuel supply, all 4 are spraying diesel so the issue is not with the fuel system. Also cleaned up the contacts on the fuse for the glow plugs and this seemed to help, sounding smoother and causing less vibration - but it is still only running on two cylinders.

Disconnecting each electrical input to each injector one at a time, the engine stalled each time when disconnecting injectors 2 & 4 (L-R) but injector 1 & 3 being unplugged made no difference - so we believe we have isolated the issue here: an electrical issue with the 1st and 3rd injectors.

However, having tried already with inspecting and re-taping the wires and cleaning up the connections, we are still not entirely sure what the issue is - all we can think of is a wiring problem further away from the injectors or potentially an ecu problem.

We'd really welcome any suggestions regarding this issue and I'm happy to respond with extra information if needed. Thanks in advance.

[Black dog]

The ECU shuts off signal to the injectors on these engines when it detects open circuit.
You need to reset the fault with a code reader and it will be all good.

[MSwift]

Thanks for the info - we have plugged in a scan tool which has revealed 0 codes stored, so it would appear there isn’t anything to erase or reset. Any other thoughts?

[Black dog]

Not all obd readers will see the codes. Select erase faults anyway and see if it clears. If not better tool will be needed.

[MSwift]

We did attempt to choose “Erase Codes” but as the reader hadn’t picked any up this didn’t work. May be worth mentioning there are no lights on the dash or messages on the info panel.
Today we’ve tried disconnecting the battery and leaving for several hours to see if this would make some sort of reset happen but no luck.

Do you think VIDA would be able to reset it? We do know someone who has access to it but just wanted to give our tool a go first.

[Black dog]

Yes Vida will do it. There will be codes logged for injector circuit as you cranked the engine with them unplugged.
It may not put any lights on as it's not classed as an emmisions fault.

[MSwift]

Update: VIDA found no codes so unable to do anything from there. Thanks for your suggestion anyway as it was worth ruling out.
Having spoken to a Volvo specialist it has been suggested that the ECU is sent for diagnosis and repair so that’s the next step.
It’s possible that it has been affected when the engine was turned over with the injectors unplugged.

[John s40 D]

Disconnecting piezo-type injectors could cause them to fail.

https://www.techtips.ie/Bosch/piezo-...njectors-1.pdf