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MG MGF Technical - Wrap up of alarm ECU problems on Aussie MGF 75thLE

Guys, you may recall a thread I wrote a few weeks ago concerning the problems with my car security system. Basically, I could only use one handset, the alarm light on the dash wouldn't flash and in the end, after about 3 weeks of this, I'd have to pull the alarm fuse and then put it back to be able to start the car. When I eventually got the car to the dealer, the testbook computer system couldn't 'talk' with my car properly as the screen would fill with 'garbage'. In the end, it certainly appears that the alarm ECU was faulty and has since been replaced and the security aspects are resolved.

That's the good news, but a few things still don't quite add up. First, when I open the drivers door, the interior lights are not coming on, but they do when the pax door is opened. Second, a buzzer is supposed to sound if you leave your lights on - it don't. Third, isn't the red LED on the dash is supposed to glow when you remove the key from the ignition - it don't but it will when I set the alarm. Fourth, I've noticed an annoying static or interference through the AM band on the radio that wasn't there before.

Is it possible that the alarm ECU could be causing interference with the radio? Any thoughts or suggestions on the rest of the problems? I suppose there could be a connection problem in the driver's door - could that contribute to any problems with my original alarm ECU? Does the alarm ECU as fitted to the F, interchangeable with the Rover 75 or with any of the Landrover range of vehicles?

I'm also thinking of going the ITG Maxogen route @ AUD$1000. Should I consider the K&N or the Viper? Any advice on which system is the better in terms of improvements in performance and economy? Any damaging side effects that I should be aware of? I can't think of any myself but then I'm not a mechanic.

Any help or advice would be gratefully received.


Hi again Phil,

Firstly I don't think the red LED is supposed to glow when you remove your key from the ignition. It should flash rapidly after you set the alarm and after about 30 seconds it should flash slowly.

From your description it sounds like there is still a fault with your driver's door switches in the lock. The door ajar switch is not working. One switch in the lock tells the system that the door is locked. Another switch indicates when the door is open or closed. This situation may cause the superlock to malfunction ie only one flash of the indicator lights when you attempt a superlock.

I have also noticed that the Alarm ECU seems to interfere with the AM band on the radio. There was a thread on this about a month or so back. I used a portable radio to check this out and found that the interference built up when I approached within a few feet of the car. I must confess to not trying it with the alarm switched off but I will do so next time I use the car.

Can't advise on the airfilter business except to say that introducing cold air into an engine does produce significant gains in power. I first noticed the reverse of this when learning to fly some years ago. Carburettor heating is a must on some aero engines to prevent icing up. To test the system we switched to heated air while the engine was running at 1700 rpm. With warmed air the revs dropped significantly indicating the system was working. The drop in power was very noticeable.


Bruce Caldwell

I agree with what Bruce said above except that the LED should glow after you remove the ignition switch - but not immediately after. It glows steadily (not flashing) when the immobilizer alone is set (not the alarm). It gets set a few seconds after you remove the key from the ignition and open the passenger door - which would confirm that there is something wrong in your door switch as the alarm ECU doen't seem to get the door open signal (also the lights that don't come on).

Spyros Papageorghiou

Thanks Guys, I do recall prior to my ECU problem, that when I removed the key from the ignition, after a short while, I would open the drivers door and the LED would glow (not flash). This is now not happening and I presume this may be related to the drivers door lock problem. The car is locking and superlocking just fine and I tested the volumetric sensor last night and it's working fine. I think I'm almost there but not quite.


Yes the LED glows continuasly when the drivers door is open, you have a faulty door lock mech, this also operates the lights on buzzer
Will Munns

Thanks Will, I thought as much.



Oh and BTW, has anyone got a fult with the door locks on an older MGF drivers door (not working lights/plunger/superlocking etc)? come to the Luton meet and I'll see if I can fix it (no promises though)
Will Munns

This thread was discussed between 14/08/2002 and 15/08/2002

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