1987 CQ cut out and now won't start

[MGaz]

I was driving through town and it cut-out briefly but didn't stall.

I pulled up to some lights, and it died.

Haven't been able to start it.

Was making a clicking noise as if battery was flat, but I saw no battery light before it died.

Multi meter reads over 12volts on the battery.

It has an old COBRA alarm, immobiliser; model 7925.

I was able to get ignition lights before but now I can't even get that.

Windows work fine etc.. so can't be flat.

I'm lost as to what it could be?

I've trIed putting the immobiliser code in via the key turns.

Nothing.

[John.]

Getting ignition lights and then not sounds like it's maybe a bad/loose connector somewhere?

I'd be for visually checking the connectors at the fuse-box and ignition switch, if all looks ok, then if you're handy with the multimeter and wiring diagram ....get probing ! ..... don't forget the earth straps too !

[MGaz]

Getting ignition lights and then not sounds like it's maybe a bad/loose connector somewhere?

I'd be for visually checking the connectors at the fuse-box and ignition switch, if all looks ok, then if you're handy with the multimeter and wiring diagram ....get probing ! ..... don't forget the earth straps too !

Before the ignition lights and centre console lights stopped working entirely, there was 12 volts showing on the cars LED volt meter.

But as soon as I tried turning the key, it shot down to the bottom and the starter moter clicked and ignition lights faded , just like a flat battery.

but the battery is fine, I think.

Now of course, no ignition at all, but the cobra immobiliser led is still responding to putting the code in with the key turns.

It's just refusing to give me ignition or any other instrument lights etc.

Maybe a Fuse is blown now, too?

i noticed some green stuff on the pins of one of the relays, too! ?

[John.]

.....as soon as I tried turning the key, it shot down to the bottom and the starter moter clicked and ignition lights faded , just like a flat battery.

What you're describing is you have battery voltage but then it drops under load, either the battery is goosed (unlikely to have caused the original problem as engine was running and power supplied by the alternator) or there's a poor connection/high resistance ....... you have a "click" from the starter so ignition switch "may" be ok. Try bypassing the supply and earth using jump leads between the battery positive and where it connects to starter solenoid.......and between battery neg and engine.
The above could done with a voltmeter to pinpoint the exact point where the problem is (volts drop test), but you may need an accomplice ?
If it were my car I'd be checking the engine earth strap, if it's the braided type it may have corroded over the years and is falling apart, locate the strap and give it a yank, it shouldn't come away in your hand.
The above may also have caused the battery to discharge while driving due to the alternator using the same cabling ?........so maybe worth swapping the battery with a known good one?

Your green relay, wouldn't do any harm cleaning that up.......do you know what relay it is?

[Ian Simmonds]

As John suggests, check out the earth straps and cables for the engine, starter motor and alternator.