Sprinter won’t start - is it my key or glow plugs?

[Cosmocattell]

My sprinter isn’t starting. The glow plugs light has been staying on for a few minutes when driving over the past month. I’ve only driven it a few times but it was starting fine. The other day it didn’t start but I jumped it fine and ran it for about an hour. Today it won’t start at all I’ve been trying to jump it all morning and it ticks over and sounds like it’s about to start but it just doesn’t get there. It’s booked into the garage to fix the glow plugs but I have to get it there today. The other thing is the only key I had snapped and I got a new one cut at the weekend. Might this be why the van isn’t starting today? They gave me the old key back and it doesn’t look like they’ve opened it up to take the chip out or anything. Need to get it started most importantly so I can get it to the garage

[paintman]

Based on my 208cdi 2002 Sprinter.

The glow plugs aren't really needed, an opinion shared by a van specialist I deal with & the mechanic they use. Mine haven't worked for years. Even Beast from the East mine was fine.

The security chip needs to be in the position it would be in in the key in the ignition. If it isn't & the chip is in the broken end of a key which is hanging off the same split ring as a good key but without a chip it might run, it might not run, it might cut out while driving. Tape the two together & it should be OK.
I needed a new key in the past few weeks - one with a slot for the chip - & I checked with my local Timson's who've done them for me before. The difference this time is that their machine was able to both read AND program a new chip whereas previously it could only read, not write.
IIRC £45 for new key with new chip so I'm now back to two transponder keys without a Mercedes mortgage.
My key is this type: http://www.ebay.co.uk/itm/like/282725758320

Had an issue a couple of years ago where it would start & run for a few seconds first thing in the morning but would then cut out & take a fair bit of cranking before it would start. After which it would be fine for the rest of the day including being off for several hours only for a repeat performance the following morning. Turned out to be fuel draining back to the tank caused by a faulty one of these which sits on top of the fuel filter:
https://www.ebay.co.uk/p/Mercedes-Benz-A6110780249...

Edited by paintman on Monday 23 April 15:49

[Penelope Stopit]

As above, have the broken key up close to the ignition switch

[TooMany2cvs]

Cosmocattell said:

The other day it didn’t start but I jumped it fine

Jump-starting will only work around a shagged battery. When it "doesn't start", is it still turning over quickly on the starter?

[Cosmocattell]

Thanks for replies. I've called Timpsons where I got the key cut and they said they did swap the chip over to the new key so it shouldn't be the key.

Yes it turns over quickly and sounds just like it's about to start every time but it doesn't.

I'm only guessing it's glow plugs because the light has been staying on when I've been driving it. I was under the impression faulty glow plugs prevent you being able to start the engine, is that completely wrong then?

The garage has actually come and towed it now and based on what I've told them they're presuming it's glow plugs as well but if it might be any other issue such as that faulty fuel filter valve it would be good to know.

[TooMany2cvs]

Cosmocattell said:

I was under the impression faulty glow plugs prevent you being able to start the engine, is that completely wrong then?

Diesels rely on compression to ignite the fuel-air mix. That's a lot easier when the cylinder is warm - and so glow plugs warm it up initially. But modern common-rail diesels ignite fuel at such high pressures that they ignite very easily anyway, and the glows aren't needed in the UK. What modern diesels do use the glows for is for better combustion, for better emissions, even when warm - and the ECU monitors their performance. If it detects them being a bit iffy, *ping* on comes the light.