Hi, i have a 1997 110 300 tdi, recently it has been cutting out whilst driving, mainly on longer journeys , doesnt seem to do it on short hops. I have got new fuel filter. Doesnt slowly die like a fuel starve just cuts out. I then turn off ignition, wait for immobiliser to arm, then cancel immobiliser and attempt to start, this may take several goes to start engine. Also arm and disarm alarm manually. This problem can also occur if i switch off then attempt to start again shortly after. Ive cleaned connections and earth points to no avail, anybody got any ideas? could it be the alarm or immobiliser system?

This seems very similar to my issue. Doesn't look like anyone commented though ..... Help ?

I realise you'll have yours sorted by now ;-) ...... Either that or I now own it !,

Lhainsworth said:

This seems very similar to my issue. Doesn't look like anyone commented though ..... Help ?

I realise you'll have yours sorted by now ;-) ...... Either that or I now own it !,

Click to expand...

As they last logged on in 2014 there's every chance that you own it.....
Does yours do it sporadically or is it a fairly regularly thing?

If it splutters - it's usually fuel related
If it just dies suddenly - it's usually electrical - check for chaffed wires or water shorting stuff (under the drivers seat is a fav)

Good evening all. My 90 (300 Tdi) is cutting out too. Had an intermittent problem for about a year; first it was refusing to start after stopping for a short while (for example for diesel) but after a while it would start again no problem. A few months ago it started cutting out suddenly with no warning (no spluttering, although a couple of times there has been a bit of a 'whumph') whilst I was driving. To start with, it seemed to be when I was pulling away and speeding up, or going around roundabouts, but recently it's started cutting out when at speed. Three times in the last two days! Before that it cut out on 13th Feb, but before that it was prior to Xmas - so it behaves for a while then starts playing up just when I've relaxed! I can start it again almost immediately by turning the key for a few seconds to turn the starter, turn off and try again. After several attempts she roars into life and drives as if nothing's happened. My local garage who've looked after my Landy for years are stumped; they've changed everything to do with the fuel supply (fuses, pump, filters etc) and are now fixating on the idea that it must be the immobiliser. I've always thought it must be fuel starvation (or bad fuel) but, Dragonwalker, if you're right then it's not fuel-related after all. Another thing - I doubt it's related to this problem (please correct me if I'm wrong), but my lights fuses have also been playing up for a time; the driver's side side-lights and dash kept blowing, and I've discovered that pushing the fuse in only half way has stopped it going pop. However, the fuse next to it (brake and reversing lights) is now blowing when I put her into reverse. Could it be something behind the fuse panel causing all the problems? Where else should I tell my garage to look? And is it likely to be anything to do with the immobiliser if the starter motor works ok? Many thanks in advance for any assistance!

Immobiliser has two halves, one stops the starter working and the other shuts the FIP off. If you look in the battery box on the front of the seatbox there is a black box about 3 inches square, that is the immobiliser. They are prone to dry joints on the relays inside which can cause problems like you describe. Next time it doesn't start give it a good thump and try again, if that cures it then unbolt the box and grind the rivets off which hold the box closed, inside is a plastic box which you can unplug and then slide the circuit board out. Resolder the relay terminals and reassemble. Many will say bypass the immobiliser but I prefer it working properly (plus you may get a insurance discount for a factory fitted alarm / immobiliser), if you bypass it you should really tell your insurance company.

Thanks Kwakerman, will investigate that approach. Is it easy to bypass the immobiliser temporarily, or is it irreversible once done?

Everything is reversible if you plan it properly, but for the extra hassle of running additional wiring to the starter and solenoid and then connecting it in to the electrics at appropriate places you may well be better off just pulling the box apart and resoldering the relays as the first course of action.