URQ 1990 20v Aftermarket alarm / immobiliser

[predding]

Having replaced the battery, motor spins well but engine not firing at all. 1990 Immobiliser fitted and been OK until now - it will arm with red indicator lit and disarm with indicators flashing BUT when armed, if I open the door manually with key, the siren will not go off or indicators flas like it used to do ie the cabinn sensors are not picking up the movement/air pressure change which it used to do. So even if I disarm the alarm, I am thinking the system has had its day and the sensors are not releasing the ignition circuit. Pictures attached of the unit LCB Remote Alarm Professional Part No 2000 which is very much of its era . It was also connected to the remote vacuum door locking and now, it wont send a strong enough signal to the vacuum pump to lock/unlock the car

I can do this with the key in the drivers door - lock unlock no problem. So all in all I think its tired but not being an auto-electrician, am nervous about getting all the connections correct again with a unit wiring diagram. I have the cars wiring diagram and can try to track all the wires from the ignition switch.

So:

1 . Recommendations/comments welcome and long shot, does anyone have a manual for this unit.
2. On the 20v does anyone know which Low Volatge terminals on the ignition coil to check for a 12v feed from the ignition switch

On the wiring diagram link, you can see Track 59 the ignition coil Item N but I cant tell which are the terminal / numbers that come from the ignition switch http://www.sealtd.net/quattro/ishamr...yp85/47_03.png

Cheers

[Tractor Dave]

Pull it all out

[Henkjan]

+1

aftermarket alarms are a non starter waiting to happen. the only question is when they'll fail.

[Tom_]

As Dave said, remove it...I had a similar alarm/immobilizer and one pin inside the connector was burnt completely so I am glad that the car didn't burn completely. Most of these wiring installs weren't done correctly back then.

[predding]

Thanks - this seems to be the general consensus so I will be doing that. TBF to the original installer, they matched the correct male/Female connectors to the Audi originals so I can replug them together ie they added their own Male/Female counterpart and then spliced into THEIR wiring tails. The Main power one has a few splices; I can tell that one as all the relays inside click when I plug that connector in. Pretty sure this was done for the 1st company director owner ie it was a professional installation.

You can see they installed the entire loom ie not hacking it around. I did drill out the tin rivets to reveal the pcb and relays but couldn't see anything overtly burnt out. After all these years it will likely be a dry or corroded joint in the wiring connectors

I briefly connected the original white connectors together with the main power on connected to the box for continuity but need to carry on today carefully unsplicing the the power feeds. It was odd that even with the ignition off, the Red and Green Engine oil LED cam on so their is something not right about the power crossover. But as I said I want to remove it as it's a future source of failure and dont want to be out stranded somewhere.

Can anyone advise where to test for an ignition feed on the coil using a MM - thanks

[John.]

Can anyone advise where to test for an ignition feed on the coil using a MM - thanks

The connector that goes to + The other low tension connector is the switching side, if your MM has a dwell function then you should be able to check for switching to earth. I've never had cause to check this on my 7A so can't say what figure the dwell should be ?

[predding]

Thanks John.

I have now checked the 12v feed to coil terminal 15 with ignition on and I am getting 12v feed to coil Item N http://www.sealtd.net/quattro/ishamr...yp85/47_03.png. So next step is to check if I have a spark at the plug...

I have checked connections to immobiliser and now the siren is working as it should ie with alarm armed and opening door using key.

However (there is always a but), whilst the Central Locking locks/unlocks on the key in the drivers door it will only unlock using the alarm remote control ie it hasnt got enough grunt to send a signal to the actuator in the drivers door to lock it - see good article from link from Kerbside Motors / Seal Ltd http://audi.humanspeakers.com/power-locks-85.htm

Now I need to find out how to get door card off to check switch/actuator as the 1990 20v door card fixing is different to the explanation in the Haynes manual

[predding]

Update. Door card is off with no damage thanks to excellent post in Classic Audi forum. Can now see the aftermarket actuator and crap piece of bracketry they used to hold it in which will get sorted. I take my above TBF comments back, whoever did this install was a moron, probably same cretin that nailed the mobile phone holder to the passenger dashboard in 1990. They really didnt care back then did they?

[newsh]

Update. Door card is off with no damage thanks to excellent post in Classic Audi forum. Can now see the aftermarket actuator and crap piece of bracketry they used to hold it in which will get sorted. I take my above TBF comments back, whoever did this install was a moron, probably same cretin that nailed the mobile phone holder to the passenger dashboard in 1990. They really didnt care back then did they?

Any time I see a Scotchlok I apply idiot status!

[predding]

I managed to get the immobiliser auxilliary lock rack & pinion drive unit out and lubricated it with WD40 which at least made it operate smoothly again. However, the angle of the rods and mounting of the motor isnt great so have just removed it as it provides no smart feedback to the alarm. The original central locking now works alot better on the key thanks to not having to drag this appendage mechanism along with it...

[predding]

The connector that goes to + The other low tension connector is the switching side, if your MM has a dwell function then you should be able to check for switching to earth. I've never had cause to check this on my 7A so can't say what figure the dwell should be ?

Thanks again John. I am getting no HT voltage out of the coil (main lead). I am going to check your suggestion to check earth on this diagram Track 56 Brown/Red wire to earth. I am getting 12v on the T15 with ignition on but need to understand what the symbols 2/1 3/31 and 1/15 are - I think these are the terminals in the rubber booted plug that plugs into the coil that I am measuring wch plugs into the power amplifier N70 Track 56-57 on the diagram http://www.sealtd.net/quattro/ishamr...yp85/47_03.png

The only thing I did while working on the car was to remove the coil and clean it all and paint the base plate with KuRust so was wondering if this neutralisation could have affected the earthing of the coil assy to the body. It has also been suggested that the actual coil may have failed so I need to find out if it can be tested...