Low voltage to glow plugs?

[simonwedge]

I have a 2006 S60 2.4D 163bhp. Starting from cold is not great, sometimes it cranks for quite a while before starting and when it does start it runs 'lumpy' and revs can hunt up and down. It's fine once it's warmed up a bit.

So far I've checked the glow plug resistance and they're fine. I've got VIDA and I've run the injector test within that and they're all within specification. I've also done an injector leak back test and again all is fine.

There was an old code stored on VIDA of 'ECM6662 Glow relay control - faulty signal' which I initially thought related to the Glow Plug Relay but subsequently found was actually pointing at glow plug number 2. I have replaced this with a known good used glow plug.

I have just done a test of the voltage supplied to the glow plugs with the ECT sensor disconnected and it's only supplying around 2v to the glow plugs. Is this correct - I was expecting 11-12v? If it's not correct why would this be - Glow Plug Relay or something else?

[cheshired5]

Pretty sure all Euro 4 D5 glow plugs have a lower voltage.
In my glow plug change video, they're 4.4V but 7V are on some models.

The Information >Product Specifications >Signal Specs section of Vida should confirm and the part number shown in the parts catalogue will lead you to the correct aftermarket equivalents.

[simonwedge]

Simon - thanks. Looking up the correct part number on VIDA it shows 8653880. On the Autodoc website it shows two options when you search generally under 2006 S60 - one is rated at 4.4v and the other at 11v. The 4.4v one maps over to the part number shown on VIDA.

So, if the correct glow plugs are rated at 4.4v is a 2v power supply reasonable or should it be nearer 4 volts or so?

If the voltage is OK I then wonder if someone may have put the 11v versions in at some time and this may be the problem? Is there anyway of testing to see which ones I have?

[simonwedge]

Have answered my own question to a degree - I've dug out the glow plug that I removed from the car and it's a Bosch 0250403001 which is listed online as a 4.4v item so it appears the ones in the car are of the correct specification.

My question remains though of whether 2v supply is correct or should it be higher?

[cheshired5]

I can't think of any way to be certain of what's currently fitted without removing every one and inspecting any markings.

Did you pull the coolant temperature sensor plug before checking the voltage at the glow plug connectors?

[simonwedge]

Yes, disconnected ECT sensor before testing