[jaap]

Hi,



I have an intermitent non start issue with my car. The car has an aftermarket immobilizer which I suspect is causing this problem. When I go to start the car I deactivate the immobilzer with its electronic key. The light goes out but when I turn the key the starter motor is turning but the car does not start. Then I remove the ignition key, wait for the immobilzer to activate itself and perform the same procedure. Usually the car then fires right up but lately I sometimes have to repeat this procedure a number of times. When it does start everything is fine. So it either does not start at all (no sputter/stall) or starts normally.



I know the immobilzer influences the starter motor because it does not turn when the immobilzer is active. But I wonder what else is in general disabeld by an immobilzer: DME, igniton coil, fuel pump? I have looked under the dash but can only see many black wires going from the immobilzer into the wiring loom.



Jaap

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[flash]

if i were designing an immobilizer, i would deactivate the DME relay. that would be the simplest thing to do. unfortunately it could also mean that it confuses the ECU related to the alarm system, which goes through it.



i would start there

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[vliegwielolaf1234]

Jaap



I would take the imobelizer out before it takes you out .



It is not that difficult . if you understand electricity a little .



It is just a mather of following the wires and restoring the old connections .



just make sure you take your time and work and restore the connections one at a time so you do not make any mistakes .

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[jaap]

Olaf, that is what I intend to do but would first like to confirm it is the immobilizer by measuring the signals influenced by the immobilizer. The problem is the unmarked wires from the immobilzer go all the way back into the wiring loom that goes up into the fuse box. I either need to remove the seat to be able to get under the dash for a good look or take out the fuse box, which I suspect is how they installed it in the first place. However taking out the fuse box really scares me becuase there are so many wires that could break or short.



Jaap

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[vliegwielolaf1234]

[quote name='jaap' timestamp='1337360328' post='127074']

Olaf, that is what I intend to do but would first like to confirm it is the immobilizer by measuring the signals influenced by the immobilizer. The problem is the unmarked wires from the immobilzer go all the way back into the wiring loom that goes up into the fuse box. I either need to remove the seat to be able to get under the dash for a good look or take out the fuse box, which I suspect is how they installed it in the first place. However taking out the fuse box really scares me becuase there are so many wires that could break or short.



Jaap

[/quote]



The trick is to follow them , and at the end there wil be a marked original wire , then you wil be able to indentify it by position and color with the diagram in the workshop manual .

You have to get under the fusebox and there should be room to work with once you get it loose , otherwise they could not have installed the wires .

The wires don´t break that easy , neither will the fall appart that easy .

Disconect the battery before you start , then you don´t have to worry about shortening things out .



And yeah you have to stay kind of flexible to work on the 968 . especially if you want to get under the dash

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[jaap]

Today I was able to have a look at the fuse box panel. The wires are long enough to allow the panel to be partly lifted out to have a look under the panel. Using the wire diagrams I can confirm the immobilizer sits between the starter relay and also between the DME and DME relay effectively controlling operation of the fuel pump. The ignition system is not part of the immobilier. I also found it monitors a wire that holds the signal of the door contact switches but not sure why. Of course the car now start the first time so will have to wait till the no start condition occurs to measure if the DME relay gets its input signal. Obviously the starter relay is not the problem becasue the engine always turns.

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[PhilG968]

I am curious if I have an after market one as well. Does anyone else have to hold their high beam switch in while starting the car?

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[vliegwielolaf1234]

[quote name='PhilG968' timestamp='1337797685' post='127289']

I am curious if I have an after market one as well. Does anyone else have to hold their high beam switch in while starting the car?

[/quote]

nope , not original .

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[PhilG968]

Thanks

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