Would bad glow plugs cause car to stall when warm???

[PhilUK]

Hi All,

I have had Carly showing faults codes for 4 glow plugs the glow plug module for some time and have been meaning to replace them on my 35d E70. The car has been spluttering when cold started more and more recently and the other day when driving with car up to normal temp it stalled and has happened a couple of times since  >:(

Since been checking through the cars parameters via Carly and noticed the coolant temp is only reaching 62 degrees when it should be approx 88 degrees so I am guessing a faulty thermostat is maybe whats caused the glow plugs to burn out.

I plan to replace the main thermostat, all 6 glow plugs and glow plug module. And while I am in there I also plan to delete EGR + EGR cooler and get ride of the swirl flaps just in case 

My question is could the glow plug/thermostat issue have caused the car to stall under these circumstances?

Thanks in advance. 

[X5Sport]

It’s a possibility, though to be honest I would be a little surprised.  The engine temp might be an issue as the car engine management system may be trying to decide whether to stay in ‘cold’ or switch to ‘warm’ running.

If the air temps were low as well then that might mean the plugs are running a bit, but I thought that once a diesel was running then that was pretty much that.

If you have a DPF (you almost certainly do on the 35d) then failed plugs will be preventing a regen and that will be causing airflow restrictions down the exhaust which might also be disrupting normal engine operation.  Low temp will also prevent a regen.

Best to get both fixed before your DPF dies as they are very expensive and a faulty one is an automatic MOT fail from 20th May this year.  A giveaway will be a lot of soot at the tailpipes whereas a properly working one will have almost none at all.

[PhilUK]

Thanks X5Sport.

Will be getting thermostat, glow plugs and module replaced in the next couple of days but just concerned the stalling issue may still be there afterwards. 

[X5Sport]

The trouble is you can’t be sure with existing faults in place.  Worth using Carly to check the state of your DPF too.

[snrbrtsn]

Along with other faults As mentioned above.
I’d almost certainly suggest you have a gummed up inlet manifold, only real cure is removal for cleaning or replacement... fortunately to get to the glowplugs and module this has to be removed

[PhilUK]

[quote="X5Sport"]
The trouble is you can’t be sure with existing faults in place.  Worth using Carly to check the state of your DPF too.
[/quote]

Does the DPF regent section within Carly also tell you if the DPF currently needs a regen?

I have pad the £10 for the regen facility but have not used it yet.

Might be worth mentioning I have noticed a big lack of power over the past few weeks, I guess if a regen is well overdue it would cause this?

When you use the Carly regen facility is it immediate or do you still need to keep above a certain speed for a certain length of time?

[PhilUK]

[quote="snrbrtsn"]
Along with other faults As mentioned above.
I’d almost certainly suggest you have a gummed up inlet manifold, only real cure is removal for cleaning or replacement... fortunately to get to the glowplugs and module this has to be removed
[/quote]

I started the strip down this evening and the inlet manifold is surprisingly free from CBU  Gave it a good clean with EGR cleaner and a flushout with a power washer all the same. 

[snrbrtsn]

[quote="PhilUK"]
[quote="snrbrtsn"]
Along with other faults As mentioned above.
I’d almost certainly suggest you have a gummed up inlet manifold, only real cure is removal for cleaning or replacement... fortunately to get to the glowplugs and module this has to be removed
[/quote]

I started the strip down this evening and the inlet manifold is surprisingly free from CBU  Gave it a good clean with EGR cleaner and a flushout with a power washer all the same. 
[/quote]

Well there goes my suggestion out the window, sorries I stand corrected, I’ll go and stand in the corner
Great work undertaking yourself!
The reason I’d suggested is the mention of lack of power and stalling, typical traits of a gummed manifold!

[PhilUK]

[quote="snrbrtsn"]
[quote="PhilUK"]
[quote="snrbrtsn"]
Along with other faults As mentioned above.
I’d almost certainly suggest you have a gummed up inlet manifold, only real cure is removal for cleaning or replacement... fortunately to get to the glowplugs and module this has to be removed
[/quote]

I started the strip down this evening and the inlet manifold is surprisingly free from CBU  Gave it a good clean with EGR cleaner and a flushout with a power washer all the same. 
[/quote]

Well there goes my suggestion out the window, sorries I stand corrected, I’ll go and stand in the corner
Great work undertaking yourself!
The reason I’d suggested is the mention of lack of power and stalling, typical traits of a gummed manifold!
[/quote]

Ha-ha  ) I was expecting exactly as you suggested so was surprised when both the EGR and intake manifold were pretty clean. I guess it now points to the DPF needing a regen.