A strange problem.........

Mycroft H

Strange problem here with our xantia 2l hdi


Our Xantia wont start at all. Turn the key and the starter doesn't operate at all. No at all attempting to turn over. It will start on a push start but not with the key.

Battery is good. Glow plugs were replaced during the hard winter there.

Now here is the strange bit. I had left the battery unplugged for a few hours yesterday, and when I replaced it, it started fine, like it used to, quickly and without hesitance.

Now that is leading me to think that there is a problem with the ECU since it worked fine after the battery was unplugged, starting normally. However trying to start it this morning it had reverted to the state it was in before, not even trying to start.

Personally I don't think its the starter as its never given me any other problems and it starts quickly when it does start.


Any other ideas?

biko

Yeah, seems to be some electrical/ECU issue.
Try again with the disconnected battery - once could be nothing, twice is certainty.

Mycroft H

biko wrote: »

Yeah, seems to be some electrical/ECU issue.
Try again with the disconnected battery - once could be nothing, twice is certainty.

Yea thats what i'm doing now.

Going to see if lightning strikes twice

biko

Just a guess but maybe it's the immobiliser? And it's being reset by the battery unplug?

Mycroft H

biko wrote: »

Just a guess but maybe it's the immobiliser? And it's being reset by the battery unplug?

Yea i was guessing that to, but it started by push starting.

I was fairly sure that an immobiliser would disable the starter and fuel injection pump if the key was unrecognized but I'm not entirely sure how the immobiliser system on the xantia works.

alias no.9

A HDi is going to need the ECU to be happy even for a push start so I think that and the immobiliser are unlikely to be the problem.
Can you hear the starter motor relay clicking when you turn the key? It may be the relay that's at fault.
Alternatively, when you turn off the engine in some cars, you need to turn the key fully to the off position before you will be able to start it up again, is it possible that there is a problem with the ignition switch contacts and the ECU thinks that the key never went to the fully off position. Disconnecting the battery will overcome this and hey presto you can start again.

Mycroft H

alias no.9 wrote: »

A HDi is going to need the ECU to be happy even for a push start so I think that and the immobiliser are unlikely to be the problem.
Can you hear the starter motor relay clicking when you turn the key? It may be the relay that's at fault.
Alternatively, when you turn off the engine in some cars, you need to turn the key fully to the off position before you will be able to start it up again, is it possible that there is a problem with the ignition switch contacts and the ECU thinks that the key never went to the fully off position. Disconnecting the battery will overcome this and hey presto you can start again.

Okays I just reconnected the battery there after more then an hour of being disconnected. Not starting.


I can hear what i presume to be the relay softly clicking beneath the steering wheel near the fuse board.

peasant

Some good, old, low-tech wiring problem perhaps?

Starter pulls massive current, any loose connection, corroded plug/wire could up the resistance to such a degree that the current doesn't get through. Also check the earth side of things.

Reconnecting the battery might have jiggled a bad wire just enough to make it work once more

Andrew Campbell

Top of the list is starter motor, second is the battery connections

Guy:Incognito

A simple one to overlook that could be the issue is the connections to the battery itself. Are they tight and not moving? someone damaged the nut on the connection to tighten on my Xantia and it can start perfect one minute and have absolutely no reaction the next because the connection is slipping. It's just a case of putting a new nut on to tighten it.