1991 518i engine immobilizer - a newbie posts!

[dignityandpeace]

Hi people!
Please be gentle, this is my first post!
My question is this - I have recently purchased a 1991 518i 5-speed manual from a guy who had not owned it long, but had done so long enough to encounter a problem with the engine immobilizer tripping in when using the regular central locking key. He was not sure why/how this happened, but it has happened to me twice in two weeks, and it's a drag as I have to wait 15 minutes before it re-sets and the engine can be started. What is causing this, and can it be de-activated, even if that means losing the immobilizer function completely?
I throw myself at your mercy...
Cheers,
Alan

[Phil Sanderson]

[QUOTE What is causing this, and can it be de-activated, even if that means losing the immobilizer function completly [/QUOTE]

Hi Alan,
I had a similar problem with my 525i a few years ago. It was the alarm module located under the back seat (see pics). Even if yours is not exactly the same as mine, look for something similar and disconnect it to see if this removes the immobilizer.

[Gayle]

Welcome Alan. No need for fear. This board is usually very nice to newbies plus we have all just had our knuckles rapped so we are on especially good behavior now. We could use some peace and dignity now.

While we are waiting for others who are more knowledgeable and helpful to arrive, how bout giving us more of an introduction to you and your car.

Please tell us where you are, how you came to buy this car, mileage, what other issues that it has that you know of, what you are dreaming of doing with it, etc. Maybe post a pic.

[Blitzkrieg Bob]

Please make sure to write us all a scathing letter of resignation.

It will help distract us from our cars...just momentarily

[dacoyote]

Please make sure to write us all a scathing letter of resignation.

It will help distract us from our cars...just momentarily

/me gets out the yard stick... now be nice....

-Charles

[Gayle]

Alan

Were you here for the big blow up of the last two days? If you have been a lurker, this all makes sense. If not, you are probably going wtf.

[dignityandpeace]

Wow people - what an unexpectedly fulsome response, especially for a Limey with a mere 518i!
Firstly, Phil, please excuse my embarrassing ignorance, but how do I remove the rear bench to get at the little green box? Yes, you really are dealing with that standard of ability!!!
Secondly, Gayle, I am the wrong side of the pond to have experienced the wrath of Katrina, but there has been extensive coverage here of the event itself and the repercussions (so far - clearly others to come still). I can't hope to imagine what direct experience of such an event would feel like, so I can only try to empathise with the unfortunate people left behind, and those who left their lives behind. Both groups deserve sympathy and support, but it seems the American people (if not the government) are wholeheartedly working to alleviate the issues that have arisen in the aftermath.
You asked where I am. Well. south-east Essex, about 40 miles east of the centre of London, in a town called Westcliff-on-Sea, which is located not on the sea, but the mouth of the Thames estuary. I don't know my latitude or longitude, but I'm sure you get the drift. The car was bought "blind" as I won it on ebay, for £531, including a personalised number plate (which I am currently trying to sell). Meantime, it trundles on, and so do I...
I shall try to attach a quick picture, but it's only taken with my phone, so poor quality - apologies to those of you to whom these things matter ;-)

Take care, and be happy!

Alan

[Qsilver7]

but how do I remove the rear bench to get at the little green box?

This is how to remove E34 sedan/saloon rear lower cushion (see diagram and pic below). If you've never removed the seat before, I recommend:
* straddle the hump with one foot on each side of tranny tunnel.
* place your back flat against the upper portion of the seat back
* raise your bum/butt about 6" above the lower seat cushion (enough room to pull upward on cushion without sitting on it
* place hands in the lifting locations and pull upward (put some grunt into it to release the clips
* get out of car and lift upward and outward to remove rear seat cushion

Once you get accustomed to how the seat comes out...you can do this from outside the car and lift up to release each side...the method above helps if the seat has not been removed since the car was put together or the 1st battery died and may be a bit harder to pull up.

WARNING: Touring/wagon rear lower cushion seat has a bit more involved removal procedure...basically the same but don't just start pulling if you have a Touring...you have to remove the lower rear seatbelt recepticle surrounds (on the Touring only) and you don't want to break or snap them off...cause it's gonna cost you money to replace them when they're broken.

[uscharalph]

This is how to remove E34 sedan/saloon rear lower cushion (see diagram and pic below). If you've never removed the seat before, I recommend:
* straddle the hump with one foot on each side of tranny tunnel.
* place your back flat against the upper portion of the seat back
* raise your bum/butt about 6" above the lower seat cushion (enough room to pull upward on cushion without sitting on it
* place hands in the lifting locations and pull upward (put some grunt into it to release the clips
* get out of car and lift upward and outward to remove rear seat cushion

Once you get accustomed to how the seat comes out...you can do this from outside the car and lift up to release each side...the method above helps if the seat has not been removed since the car was put together or the 1st battery died and may be a bit harder to pull up.

WARNING: Touring/wagon rear lower cushion seat has a bit more involved removal procedure...basically the same but don't just start pulling if you have a Touring...you have to remove the lower rear seatbelt recepticle surrounds (on the Touring only) and you don't want to break or snap them off...cause it's gonna cost you money to replace them when they're broken.

I've found that lifting one side of the rear seat at a time made it easier for me.

[Qsilver7]

I've found that lifting one side of the rear seat at a time made it easier for me.

Once you get accustomed to how the seat comes out...you can do this from outside the car and lift up to release each side...the method above helps if the seat has not been removed since the car was put together or the 1st battery died and may be a bit harder to pull up.

That's why I also included the text above at the bottom of my instructions.