I have an EF with a really strange ignition problem. About 30% of the time when you turn the ignition to on, nothing happens. Lights on the dash come on, you can hear the fuel pump but the engine doesn't turn over. This problem has my mechanic stumped. Here is what we have checked/replaced:
1. replaced starter motor with brand new one (thought it may have been solenoid)
2. Checked starter relay - working fine
3. Checked ignition switch - works fine
4. BCM/BEM seems fine

The really weird part is that when the car won't start, If you simultaneously turn the key and dip the high beams, it usually turns over...

Has anyone else experienced this problem?? I guess there is a voltage drop somewhere and turning the lights on boosts it up enough to start. Short of replacing the entire wiring and ignition system, what can I do?

Maybe a loose fuse?

Push the plugs into the bem completely.
You may find that if you tap near the left side of your knee (the plastic near it) whilst holding the ignition when it does it, the car will start.

I fixed mine by pushing the plugs in heard and making sure its bolted in tight when you put it back.

Just a guess, but mine did that exact thing

Push the plugs into the bem completely.
You may find that if you tap near the left side of your knee (the plastic near it) whilst holding the ignition when it does it, the car will start.

I fixed mine by pushing the plugs in heard and making sure its bolted in tight when you put it back.

Just a guess, but mine did that exact thing

my sisters car was doing that what i could work out was the smart lock i reset the computer and its been fine for a week now but was doing the same thing light come on but nothing happens.

what happens when u bash the dash hard

this is a common bem fault

Pity you blokes are so far away. I love these sort of faults. Look at my post on my EL. Caused by degreaser during a roadworthy check and washing of the engine bay. I progressively eliminated the cause by checking voltages in various subsections. Corrosion on relay bases was the problem of the electrical system dying at power up.

Many thanks for your suggestions -Here's an update:
I tried bashing the dash on the left hand side and this does make it work so I think the BEM plug could be loose, as suggested. I will try cleaning the contacts and pushing them in hard - if this doesn't work, I will try replacing the BEM.
cheers
Snarly66

If replaceing the smart locks does not work, i be going back to the ignition and checking the rear of the switch.This is what happened with my sons car

^^^ Yes the smarlock PCB at the end of the ignition barrell comes loose it's an easy fix

snarly i have the same probs and u know what helps me start it ,giving the steering wheel a smack from the bottom left to the right hand side in an upward motion. a electrician mate of me sis said it could be bad wiring or one of the boxes under neath the steering located on the left ( one blue and one balack) side are faulty. now please guys im no mechs a.....le but i hope i made some sense. i just turn key and give the steering a smack and it starts perfect anti theft device if u ask me lol.