Z3 Electrical problem

[Wingcowyn]

My Z3 roadster has developed an unusual problem in that it will continually lock itself as soon as I unlock it, also whilst driving along the windows will suddenly wind up on their own. This fault developed after changing the battery after the car had been in storage over the winter.
Any suggestions appreciated.
Thanks,
Peter

 

[Wingcowyn]

The roadster is a 1.8 registered in 2000.
Thanks,
Peter

 

[Tony Francis]

Have you inspected the “loom of doom” from the car body to the boot lid? There are 9 wires in there which tend to break with the opening and closing of the boot over the years. This causes weird electrical problems, some of the wires are part of the central locking system. You will need to unwrap the wiring but well worth checking. Easy enough to repair, I ended up getting a 9 way connector, i cut all the wires, reterminated them and rerouted the wires out of the rubber gasket so that they now don’t flex every time I open the boot.

 

[StephenK]

Great solution. I know my boot lid doesn’t lock with the remainder of the central locking and that was going to be the first thing I look at. I like the connector arrangement. Can I ask where I can buy that?

 

[Pingu]

Have you inspected the “loom of doom” from the car body to the boot lid? There are 9 wires in there which tend to break with the opening and closing of the boot over the years. This causes weird electrical problems, some of the wires are part of the central locking system. You will need to unwrap the wiring but well worth checking. Easy enough to repair, I ended up getting a 9 way connector, i cut all the wires, reterminated them and rerouted the wires out of the rubber gasket so that they now don’t flex every time I open the boot.

That's a good solution

It has the added benefit of making it very easy to remove the bootlid.

 

[Wingcowyn]

Hi Tony, Stephen and Pingu,
I have checked the wires and seen that some were badly worn, but still connecting. I have repaired these, but the problems remain. I also notice, that when starting, instead of starting as it usually does on the first turn of the key, it now takes 4 to 6 turns. I don’t know if the problems are connected, but there does not seem any obvious cause for the reluctance to start.
Peter

 

[Pingu]

Hi Tony, Stephen and Pingu,

@Tony Francis
@StephenK

Peter, if you use the formatting above we get an alert.

I would definitely check around the loom of doom area, and make sure that EVERYTHING is repaired. You are very lucky if you only have a simple broken wire. What usually happens is that wires short with others. Anything that is connected to any of those wires could be connected to anything else. It really is a nightmare to sort.

Tony's solution is the best that I've seen in nearly 20 years of Z ownership. I'm actually pretty flabberghasted that there is anything new to see on these cars, but well done to Tony .

The central locking may be affecting your starting via the immobiliser, but I don't think so. I'd repair the loom to Tony's standard and then recheck the starter.

 

[Tony Francis]

@StephenK I found the connector on eBay, I think it was a firm called Autosparks but not 100% on that. It came with male & female bullet connectors, I also bought some loom tape to wrap the wires as obviously you will be removing the original. Just take your time to match the wire colours carefully on each side of the connector!

 

[AntStark]

@StephenK There are various repair kits on the market for this part of the loom too. Part numbers is 61108385924

 

[colb]

Long cranking when starting is a symptom of a bad Camshaft Sensor, usually sets a code if its gone bad but not always. Worth putting a new one on given its age to see if that resolves the long crank.

 

[Wingcowyn]

Hi Pingu, Tony, AntStark and colb,
Thanks for the advice. I will fiddle a little more along the lines suggested.
Thanks,
Peter

 

[t-tony]

If you do change the cam sensor use a genuine one, or at least OEM quality. Don't be tempted to use cheap aftermarket item.

Tony.

 

[Wingcowyn]

Thanks for that Tony, Duly noted.
Peter

 

[KASPar]

@GazHyde

 

[Wingcowyn]

At the moment all these problems are not apparent. It starts on the first turn of the key and it doesn’t seem to win up the windows and lock itself without warning. I think I will just observe it for a while and see if it recurs.
Peter