V50 Engine D5 : Glow Plug System Mystery

[Yobbo]

Originally Posted by cheshired5

Multimeter set to DC Volts. 20V if it's a manual ranging meter.
Red multimeter lead into the glow plug connector, black multimeter lead on the bare metal of the engine then cycle the ignition but bear in mind the coolant temperature as mentioned previously.

It's worth saying that Dice and Vida makes this job very simple as it can activate the glow plug relay at the touch of a button and of course offer detailed diagnostic information.

I'll try that tomorrow then, also I have a VIDA DICE setup and I found that I reached a dead end regarding the diagnostic feedback - just ECM-6661 = Glow plug no.1 dead or the glow relay is dead/no distributing power, but nothing further downstream of that.
Nor could I find a way to independently activate the glow plug relay, do you know which section that might be in?

[cheshired5]

Assuming you have the D5244T13, it would seem that Volvo no longer give the option to remotely activate the glow plug relay in Diagnostics >Vehicle Communication >ECM >Activations
Vida allows this on my 2002 D5244T hence my assumption you'd be able to do similar.

You can at least view the glow plug relay status in Diagnostics >Vehicle Communication >ECM >Parameters
This may be of limited use though considering the time delay between the glow plug relay being activated (or not) and Vida giving live data following ignition turn on.

[Yobbo]

Originally Posted by cheshired5

Assuming you have the D5244T13, it would seem that Volvo no longer give the option to remotely activate the glow plug relay in Diagnostics >Vehicle Communication >ECM >Activations
Vida allows this on my 2002 D5244T hence my assumption you'd be able to do similar.

You can at least view the glow plug relay status in Diagnostics >Vehicle Communication >ECM >Parameters
This may be of limited use though considering the time delay between the glow plug relay being activated (or not) and Vida giving live data following ignition turn on.

Yes you're quite right regarding my engine number and also regards VIDA, however I had a hunch on engine bay fuse #34 - some glow plug and EGR functionality rely on it, however this tested with good continuity.

I then went on to re-test the glow plug connectors again as per your suggestion. Made sure I found a good negative contact point on the block by testing with the positive lead on the battery. Then set up for the test as per the pic in the link below.

https://drive.google.com/file/d/1xr1...ew?usp=sharing


So in this video you can see the result to cylinder #1 glow plug connector,
4.4v~ which is coincidentally the voltage rating of the glow plugs for the older chassis number < 396178!
Soooo, my glow control unit/relay is working but delivering not enough voltage for the 7v rated plugs rated for my car...

https://drive.google.com/file/d/1iaM...ew?usp=sharing

I am not certain but I believe that the ECU instructs the voltage amount that the relay must deliver to each glow plug, seeing as the relay part number has not changed between revisions it would seem reasonable to believe so, furthermore I'm having the same result with two relays. I can't reasonably expect them to be faulty if they're delivering power.

It's quite possible that a software revision for Volvo recall work (Engine Speed May Not Decrease, VOSA - R/2010/051) has reverted the ECU back to instructing a deliverable 4.4v to the glows instead of the 7v that mine would appear to need.

I guess that leaves me with two options - get some 4.4v glow plugs or see if it is possible to adjust the voltage being sent to the glow plugs using either VIDA or Elk Diagnostic software, the former seems unlikely but the latter is worth a punt.
The more you know...

[cheshired5]

If you're saying you have chassis 396179 onwards, I would be speaking to a main dealer about a software revision then rather than using incorrect plugs..... Or of course they may say your software is now correct and 4.4v are ok to install.

Basically, check with a main dealer seeing as your fault is an odd one.

[Yobbo]

Originally Posted by cheshired5

If you're saying you have chassis 396179 onwards, I would be speaking to a main dealer about a software revision then rather than using incorrect plugs..... Or of course they may say your software is now correct and 4.4v are ok to install.

Basically, check with a main dealer seeing as your fault is an odd one.

An odd one indeed!
I'll see if I can speak with a rep/master tech at my local dealership.
Thanks for your assistance on the matter!

[Yobbo]

Volvo weren't any help and their techs looked baffled, the conversation with the lady at the desk ended with "Well, we only sell genuine Volvo parts..."

Eh what? Really?? Guess I'll try the 4.4v plugs out then.

[Yobbo]

For confirmation the 4.4V plugs have done the trick which I had every confidence they would, started with no sign of bogging at 0 degrees this morning!
Obviously I have a very rare circumstance in the car's VIN stating that 7v plugs must be prescribed, and the Volvo master techs who were asked on my behalf were all clueless and to be fair it's an odd one.
However I'm glad that logic prevailed and it didn't cost me a penny in diagnostics.

I'll just have to find a new home for the new 7v plugs I've got!
Drop me a PM if you're interested, you'll be saving a small wedge.