Glow plugs?

[mr angry]

Forgive me if I have asked this before as i have posted on so many forums recently. I have a 2010 40d which is a pig to start from cold in sub zero temperatures, requiring several attempts at cranking until it eventually starts. This would suggest to me an issue with either the heater plugs, wiring or controller, however scanning the car shows no faults. Is it possible to have a fault in this circuit and have no codes recorded?

[Leslie]

Is it possible to have a fault in this circuit and have no codes recorded?

I don't think it is but then some code readers may not be able to pick it up , in sub zero the heater plugs are certainly a help though it will probably still start without them but may struggle a bit is it spinning over fast as that's important too ?

[mr angry]

I cant think of anything else that would cause this as it is definitely temp related. I used Carly to scan the car several times.

[Leslie]

I wonder if the fuse is blown would be 30-40 amp id think for the circuit would it not report back ( i dunno) as carly should certainly be finding those codes . The next stage would be metering the plugs for resistance etc to see if any are blown , I believe they are not 12v but not sure so you can't just put 12v on them or they may blow

[mr angry]

I think i will buy plugs and controller but then BMW state dont mix beru and bosch which is the most common sold

[X5Sport]

Mine certainly showed that three of six had failed but nothing about the controller - and I replaced that as a matter of routine. That was using the full version of Carly.

The good book also says to check the fuse as suggested above. It also states that the fault log should be checked and cleared.

Make sure you use a release agent too. Snapped plugs means additional expense - £800 from an Indy two years ago in my case, but what BMW might have charged is a scary thought. The new plugs were fitted with a smear of high temp ceramic grease to stop any binding. Tightening torque is 13Nm.

[mr angry]

The only thing that makes me think the fuse is ok is that the heater symbol lights momentarily before crank but worth a check

[X5Sport]

In these temps, mine is on for several seconds on both the X6 and 2 series. The warning light may be driven from a different circuit, but you may be right.

[mr angry]

That is interesting as I have only ever seen it on for like 2 secs max

[Leslie]

I actually seem my glow light on this week , first time I ever noticed it and was about -3c could well have been on before but never noticed.

[Leslie]

I think i will buy plugs and controller but then BMW state dont mix beru and bosch which is the most common sold

I think they mean don't mix actual plugs , ie change them all for one brand do not have 3 old bosch and 3 new beru and I think its very important to warm the engine before attempting removal and wd40 etc too and if it feels dodgy when unscrewing leave it in

[mr angry]

Ah ok I have read it wrong. Oddly the Beru controller operates at 12v and the Bosch plugs say they operate at 7v....am I overthinking this?

[Sandy5454]

It is a 12v car so they should be 12v glow plugs. Glow plugs do age and become less efficient and fail.
My old boat will start in any weather as long as I wait till the glow plugs have done their job- about 25 secs ( 40 yr old Mercedes engine). If your diesel car has trouble starting then there is a problem somewhere, glow plugs are on option, then injectors, timing, battery etc.
Lots of videos on Ytube show how to check suspect glow plugs.

[Leslie]

Ah ok I have read it wrong. Oddly the Beru controller operates at 12v and the Bosch plugs say they operate at 7v....am I overthinking this?

Most for sale on ebay seem to be bosch plugs with beru controller so that suggest this works just fine. Clearly if there was a voltage mismatch it would not be fine so it may just be the beru controller uses 12v input and converts to 7v output leading to confusion.

[Leslie]

It is a 12v car so they should be 12v glow plugs.

Not in this day and age it seems but will have been in the past when they were more directly wired as dropping the voltage adds complexity. 12v on a 7v plug only works the once