Engine not turning over. Aftermarket alarm?

[markb_1303]

Finally got the brakes rebuilt on the Avant and the battery had completely drained again so just put a brand new battery on the car and it won't start. Not even attempting to turn over.
battery is at 12.7V which isn't perfect but should do something.
When turning key to start position the battery voltage doesn't drop so I don't think it's trying.
This leads me to suspect the alarm system is getting in the way. It has a Piranha system from new.
The key fob currently isn't working to lock/unlock the car.
When first connecting the battery the door locks were cycling on their own seemingly at random but it's not doing it anymore.
I have the car booked in for service and cam belt on Tuesday so I need some help ASAP.

Has anyone got any ideas?

[Tractor Dave]

Some alarms require you to press the unlock on the keyfob to deactivate the immobiliser. Put a new battery in and try again. Most of us have removed the aftermarket alarms as they can be a constant source of problems.

[markb_1303]

Yes, this is what should happen but pushing the button doesn't unlock/deactivate alarm. The fob battery is only a year old and was working before the car battery went flat.
is there anything else that would stop the starter even trying to engage?

[newsh]

Ignition switch broken?

[newsh]

Try holding the alarm fob close button for 10 seconds then open button for 10 seconds.

[Tractor Dave]

Ignition switch is also know to fail. Have you touched anything else on the car? Starter motor or electrics? Have you got a water leak?
Here is a good thread written by the very clever guy UrS4boy. Don't see him on the forum much these days which is sad. Work your way through the guide step by step.

https://www.s2forum.com/forum/techni...isn-t-starting

[psiconauta911]

You can have a faulty ignition switch, try remove the instruments and disconect the ignition switch contact and bridge one of the red thick wires with the thick red/brown and see if the starter turns, if so its the ignition switch that went wrong and you can start your car with the ignition turned on and bridging this two wires to start the starter/engine! It happened to me but the ignition switch was getting harder to make contact for some time.

[psiconauta911]

Tractor Dave beat me to it!

[markb_1303]

I don't think so. It was working before the flat battery and moving to the start position clicks the relief relay
sorry - crossed post.

I'll take a look to confirm.

I've tried holding the button down (only one on mine) to see if there's a pairing thing but nothing happens

[Tractor Dave]

Is your 'new' battery defo fully charged? The click is a symptom of a battery without sufficient power to engage the starter.

[markb_1303]

I got it started.
don't ask me exactly how... Coz I don't exactly know.

I disconnected the battery a few times and on one of the times, the alarm LED turned off and the car started first time!

I still can't use the fob to lock or unlock the doors though, I suspect I'll have the same issue if the alarm turns back on again though.

[Tractor Dave]

Excellent. Now you know its the alarm you can get about removing it all.

[steve briance]

I agree with the above. My car has only ever left me at the roadside 3 times in 18 years and every single time it was related to aftermarket alarm or immobiliser. Took the alarm out years ago and the massive bodged bundle of wires was a good hint as to why it NEVER worked properly. The separate immobiliser has been a problem but that was just a loose earth and easily sorted with a star washer.

Get it all out and start again or just leave it out if you don't need it for insurance.

[John.]

Don't blame the alarm, blame the fitter !! As above, it's usually just the way it's been fitted, soldered and insulated wires is how it should be.....if you can see scotch-locks it needs sorted out.

[markb_1303]

Two days on and the key fob works again to lock/unlock and immobilise the car. My guess is the battery backup went flat and it's now charged up again.
i definitely need to remove or refit something more reliable though.

Took the car for service today, told them not to use the fob and just use the key. Typically, first thing the mechanic did was click the button and set the alarm