Today the alarm on my 98 D1 V8 started sounding on and off, uneven sounds, as I was driving along The thing is it was only the other day that I noticed the plug had been pulled off the siren by the previous owner so I reconnected and all seemed fine, locking and unlocking ok. Maybe this was happening before but I didn't notice it as it was unplugged.

Co-incidentally, a few weeks ago the car began not starting occasionally. It would turn over but not fire. Then it might start after a minute or two, or if really p*ssed at me, not for 30 mins or an hour, then when it did it runs fine. So to try to solve this, I replaced the fuel pump relay. Then when this did not help I read about the bypass plug hidden under the radio behind the dash which solves the problems of dry solder joints on the thatcham PCB. So today, I had the dash out to fit the bypass plug and saw someone had already replaced it!

So, could this be an alarm problem or a fuel pump problem? Anyone been here before and got any tips ?

I'd say an Alarm ECU issue which is a green box under the glove box. By any chance were the hazard lights flashing too?

Also you may find one of the passenger side relays may be sticking which will drain the battery.

If the battery is still functioning in your alarm sounder the removal of the vehicles battery supply the sounder will sound, the supply could be intermittant due to an iffy connection in that sounder plug/socked.
Easy way to check the sounders battery is disconnect the vehicle-battery if you have a sound then it's still ok, my battery packed up years ago.

The alarm ecu signals the 'spider' immobiliser but if it has been by-passed that's it, there's nothing to receive that signal.

Check the connections on top of the coil are clean and tight as the engine ecu/pump get there signal from the coil so no signal no pump.

But then it could be an iffy ignition amplified

Funkykipper said:

I'd say an Alarm ECU issue which is a green box under the glove box. By any chance were the hazard lights flashing too?

Also you may find one of the passenger side relays may be sticking which will drain the battery.

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No, no lights were flashing

you robbed it? :suspicious: lol

John FHA said:

you robbed it? :suspicious: lol

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Ahhh, that old chestnut