Thread: Very, very strange problem

Do you have an ECU upgrade? if so, is it a MSB or MSN ECU and who supplied it.

Originally Posted by biggin

Maybe because its pulling all the current out of your battery.
Check the battery and/or alternator.
I also recall issues with corroded fuseboards being mentioned previously, which could have an effect with higher currents.

Yes, check the alternator - if it's going, it will light up the dashboard and the high current draw from the headlights could shut the engine down. See if you battery is fully charged.

Update after checking alternator, battery, all earth points as per Rave and large loss of hair

After assistance from a local with a new Evo Nanocom (Thanks Paul).....we may have narrowed the problem down to either -
a) 19-07 Noisy crank signal detected
or....
b) 14-02 pwm signal failure from engine ECU (14 times!)

While this is of some diagnostic help....we are not sure what the pmw signal failure means so I asked Paul to check the headlights when I turned them on which subsequently was shutting down the engine and electrix...

Turns out it is the drivers headlight that was going out with passenger light still staying on even though everything else shut down????

Further investigation revealed that my IPF spotties have the highbeam/spotlight switch (Looks like small PC mouse and is mounted on the dash) wired into that headlight loom.

I removed the connector off the headlight - ran the engine and turned the headlights on - sure enough, complete engine and power shutdown so it seems that there is a possible power to earth short in the headlight loom.....or, the body control unit where the headlight signal is generated from is playing up.

Armed with this information for the auto-elex next week - I packed up and drove home.

Frustratingly, the bloody car ran perfectly all the way home. I was even confident enough to turn the lights on while driving and nothing happened

Got home and tried to replicate the problem and - nada, nix, 2 fiths of nothing..... Whatever we may have disturbed in the headlight loom or under the dash seems to stopped the short (If it is a bloody short). I can already hear the auto elex saying - "I couldn't find any problem mate"

Oh well - these issues don't fix themselves so I'll leave it to the auto elex specialist to find and solve this vexing, frustrating problem.

Cheers y'all

FWIW, the headlight circuit is running full current through the headlight switch (stalk) in the cabin, it doesn't run via a relay so might there be a short somewhere along the circuit causing the spike/dip in current?

Thanks Signal1.......

After lots of frustration and reaching the end of my tether, I took Biggen advice and swapped batteries. My 04 Disco has a high output calcium battery so it went into the problem vehicle (02 Disco) and the newer (But cheaper) lead/acid battery was placed into the 04.

Well blow me down - the problem car has ran faultless for the past week. we've had some average weather in Canberra lately so I've used lights, wipers, demister etc throughout all driving conditions and the additional load has not tripped any alarms or caused a complete shutdown of power ...which has me beat!

Oddly enough, the 04 model is running fine with the "problem" battery - go figure eh?

Admitedly the 04 doesn't have a swag of equipment requiring plenty of power that the 02 has - additional lights, ECM system, radios X2, winch, fridge etc.

All I can put it down to is an under-voltage through the battery under high load (Headlights??) which.....doesn't seem to affect the lighter electrical load of the 04.

02 Car is having a CDL fitted tomorrow so I'll take the opportunity to speak with the auto elec and seek a qualified opinion.... It realy is a strange, strange problem