Electrics: - 2003 V70 D5 Glow plug issue

Li666y · Dec 3rd, 2021, 21:04

Hi All, first foray into volvo ownership, sadly my V70 has an issue with Glow plugs. I'm hoping someone has had this issue before!

So the car really struggles to start, the previous owner had been using easy start. I changed the glow plugs for new ones but its sadly no better. The glow plugs dont get 12v to them even when frozen outside. If I bridge the relay the glow plugs get 12v and the engine starts pretty easily. So looking into why the relay isnt working correctly, I changed it for another one and still no 12v to the glow plugs. The coil seems to be getting 12v on one side, but 3v on the other side. I think its a switched earth, but I cant find a circuit diagram to work out where that coil earth goes and if it does go to the ECU, what inputs tell the ECU to earth the coil.

Thanks for any advice or suggestions!

Li666y · Dec 6th, 2021, 14:51

Hi guys,

Sorry to pester... has anyone any ideas??

Cheers, Chris

cheshired5 · Dec 6th, 2021, 18:17

Try unplugging the engine coolant temperature sensor in the thermostat housing where the radiator top hose meets the engine.

Li666y · Dec 6th, 2021, 22:36

I replaced the coolant temp sensor after I replaced the glow plugs and neither made a difference. I've just been out to the car and disconnected the coolant temp sensor and tried it again and it didn't work either.

Earlier on I called my break down recovery and he looked over it and said it's probably the air temp sensor. I've ordered one so I'll try fitting that and see how that goes...

Joe Harding · Dec 10th, 2021, 13:39

Quote:

Originally Posted by Li666y

Hi All, first foray into volvo ownership, sadly my V70 has an issue with Glow plugs. I'm hoping someone has had this issue before!

So the car really struggles to start, the previous owner had been using easy start. I changed the glow plugs for new ones but its sadly no better. The glow plugs dont get 12v to them even when frozen outside. If I bridge the relay the glow plugs get 12v and the engine starts pretty easily. So looking into why the relay isnt working correctly, I changed it for another one and still no 12v to the glow plugs. The coil seems to be getting 12v on one side, but 3v on the other side. I think its a switched earth, but I cant find a circuit diagram to work out where that coil earth goes and if it does go to the ECU, what inputs tell the ECU to earth the coil.

Thanks for any advice or suggestions!

Almost certainly a poor earth return if that is the case. Can't believe it would be that complicated to follow through

Li666y · Dec 11th, 2021, 17:14

Quote:

Originally Posted by Li666y

Earlier on I called my break down recovery and he looked over it and said it's probably the air temp sensor. I've ordered one so I'll try fitting that and see how that goes...

So I've replaced the MAF and had no joy. Error codes for MAF and intake air temp sensor still there. I wipe them and they come back. Error code for coolant temp sensor there too now :-/

Li666y · Dec 11th, 2021, 17:19

Quote:

Originally Posted by Joe Harding

Almost certainly a poor earth return if that is the case. Can't believe it would be that complicated to follow through

Any idea how to diagnose?

I cant find a wiring diagram that I can open on my phone so I cant tell where the earth ends?

Li666y · Dec 16th, 2021, 00:19

Anyone able to help please guys... really stuck here :-/

VOLVOBOY · Dec 16th, 2021, 12:11

Hi.
These may or may not help...

Li666y · Dec 18th, 2021, 17:59

It looks like 'Early 3' might be what I'm after.

Thank you very much for your help.

I'm going to take a look tomorrow and see what's what!!

Dec 3rd, 2021, 21:04	#1
Li666y New Member Last Online: Dec 19th, 2021 03:27 Join Date: Dec 2021 Location: Keele	2003 V70 D5 Glow plug issue Hi All, first foray into volvo ownership, sadly my V70 has an issue with Glow plugs. I'm hoping someone has had this issue before! So the car really struggles to start, the previous owner had been using easy start. I changed the glow plugs for new ones but its sadly no better. The glow plugs dont get 12v to them even when frozen outside. If I bridge the relay the glow plugs get 12v and the engine starts pretty easily. So looking into why the relay isnt working correctly, I changed it for another one and still no 12v to the glow plugs. The coil seems to be getting 12v on one side, but 3v on the other side. I think its a switched earth, but I cant find a circuit diagram to work out where that coil earth goes and if it does go to the ECU, what inputs tell the ECU to earth the coil. Thanks for any advice or suggestions!

Dec 6th, 2021, 18:17	#3
cheshired5 Premier Member Last Online: Dec 26th, 2021 13:42 Join Date: Dec 2013 Location: Crewe	Try unplugging the engine coolant temperature sensor in the thermostat housing where the radiator top hose meets the engine. __________________ 2002 S60 SE D5 Manual 209000 miles

Dec 6th, 2021, 14:51	#2
Li666y New Member Last Online: Dec 19th, 2021 03:27 Join Date: Dec 2021 Location: Keele	Hi guys, Sorry to pester... has anyone any ideas?? Cheers, Chris

Dec 6th, 2021, 22:36	#4
Li666y New Member Last Online: Dec 19th, 2021 03:27 Join Date: Dec 2021 Location: Keele	I replaced the coolant temp sensor after I replaced the glow plugs and neither made a difference. I've just been out to the car and disconnected the coolant temp sensor and tried it again and it didn't work either. Earlier on I called my break down recovery and he looked over it and said it's probably the air temp sensor. I've ordered one so I'll try fitting that and see how that goes...

Dec 16th, 2021, 00:19	#8
Li666y New Member Last Online: Dec 19th, 2021 03:27 Join Date: Dec 2021 Location: Keele	Anyone able to help please guys... really stuck here :-/

Dec 18th, 2021, 17:59	#10
Li666y New Member Last Online: Dec 19th, 2021 03:27 Join Date: Dec 2021 Location: Keele	It looks like 'Early 3' might be what I'm after. Thank you very much for your help. I'm going to take a look tomorrow and see what's what!!

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