Fairly urgent help required

[Jiminy Kriket 133]

I'm in desperate need of some electrical god knowledge.

 

The car/evil worshipper of satan i am referencing is a Series 1 AU wagon.

 

What in the hell goes bad in the ignition circuit that blows the engine fuse every time to turn the key to run?

 

I've been through everything i can think of. I've unplugged everything i can find. The ecu, the bcm, the engine harness connector. Pulled every relay out of the bastard and it still blows fuses like they are nothing. Blows quickly enough you can actually hear the fuse crack and see the flash.

 

I've check all the relay wiring independent of the fuse block. Pulled the fuse and applied power directly to each device and they all function as normal. Check every connection i can in the under bonnet fuse box and everything checks out fine.

 

Pulling my hair out at this stage...

 

Now for the kicker, My wife (who is 35 years old) is going for her p's tomorrow. The only car she feels comfortable driving happens to be this hell spawn of an electrical nightmare that is the au wagon.

 

well, i hope and pray that someone here can help coz this one's got me stuffed... 

[SPArKy_Dave 8,863]

The engine fuse blowing is usually the fuel pump and/or fuel pump wiring shorted,

 

Often, the wiring will melt and short out, where it runs above the tail pipe behind the rear bumper. (stupid design)

Is it dual fuel?

 

Which fuel is it running on?

The Fuel Pump is ground side switched with the relay from memory - ie, it will still short out, even with the relay unplugged.

 

I'd be checking the Fuel Pump and it's wiring first.

 

 

 

The engine fuse also powers (indirectly),

 

the Aircon compressor, via the a/c pressure switch/ magnetic clutch.
BBM sensor,

Evap Canister solenoid,

Injectors,

ISC,

TFI/Coil pack,

and some of the ecu including KAM.

[user272 526]

One day I plan to be as smart as you Dave, If you were a centipede, you'd be a good one.

[MNTL.XD 3,831]

One day I plan to be as smart as you Dave, If you were a centipede, you'd be a good one.

 

 

He'd definitely be a good centipede.

 

Become a centipede you should!

[Jiminy Kriket 133]

It is a dual fuel vehicle, currently running on petrol as it has been for 3 trouble free years.

 

If i pull the fuel pump relay and apply power direct from the battery to the power out wire in the relay socket the fuel pump runs fine, but i will double check the wiring.

 

Okay, just read your post dave and now understand that even with the power feed wire shorted the pump could run just with reverse polarity. hmmm.

 

Does the bumper skin have to come off to get to the wiring?

 

The weirdest thing about this issue is the missus only moved the car 10 minutes before i tried to start it and then it failed.

 

Anyways, you have given me some direction. I will return with further information.

[MNTL.XD 3,831]

I was just reading up on this and it was saying another bloke that had similar trouble had an auto elec have a look who replaced the fuel pump wire from near the B pillar to the pump and off it went, it was shorting. The reason Ford would say to leave 1/4 tank of fuel at all times in dual fuel vehicles is because the fuel pump continues to run even when it's switched to gas which can overheat and melt the wires.

We owned 2 AU falcons for 6 years each, the fuel pump was the only thing that ever died which was only ever once on one of them (although neither were dual fuel)

[revhead 1,392]

i had an Au dual fuel wagon in with the same probs when i lifted his cargo mat the wiring running through the floor on the left rear side of the cargo area directly above the fuel tank had been crushed and were earthing out

[Jiminy Kriket 133]

<p>Well, it's not the easy one... The fuel pump wiring checks out perfect.</p>

<p> </p>

<p>However i can stop it blowing fuses by pulling the eecV relay... Damn it...</p>

<p> </p>

<p>That just leaves everything that is controlled by the ecu... or the harness there in...</p>

<p> </p>

<p>I see many headaches in my future.</p>

<p> </p>

<p>And just for future reference, the wagons have the fuel pump wiring run down the passenger side as revhead just mentioned. so no exhaust problems in the wagons.</p>

[wagoon 2,429]

Could the ecu be faulty as in like on a circuit overtime it breaks down sort of thing?

[SPArKy_Dave 8,863]

However i van stop it blowing fuses by pulling the eecV relay... Damn it...

 

That just leaves everything that is controlled by the ecu...

 

BBM sensor,

Evap Canister solenoid,

Injectors,

ISC,

TFI/Coil pack,

and some of the ecu including KAM.

[SPArKy_Dave 8,863]

I'd go looking at ECU things which have direct 12volts to them - the Gas Controller (which cuts the injectors).

Coil pack feed.

 

Not any of the 5v ground side switched sensors.

[Jiminy Kriket 133]

All hail to the soothing sounds of Metallica whilst sorting out satans handiwork.

 

Righto, where the hell do i begin. Fuel pump wiring checked out fine. 1st problem out of the way.

 

2nd, get into the fuse panel again and look for where the short is coming from. Check.

 

Found that if i pulled the eecV relay the short on the eng fuse went away. Righto.

 

Check for shorts on the eecV relay wires, found 1. On the bloody red feed wire that powers everything that the ecu sees... Damn.

 

Traced the harness back until i got under the air box, then i found this little demon hiding in the shadows.

 

 

You see that innocuous looking self tapper screw above the 3 wires that are all torn up? That was dead set driven through the centre of the loom pulling it hard into the inner guard.

 

Thank you to the panel beater who screwed that back in after it's large front end impact.

 

So, all fixed now. Wires reinsulated, loom rewrapped (and wrapped in a piece of heater hose just to be sure to be sure) and the little bastard of a screw cut short.

 

Since we have owned the car we have had only 3 issues with it (in 3 years).

 

1 - Every time you hit the starter the battery would blow (The red wire in the middle is the starter solenoid wire)

 

2 - The neutral safety switch was ineffective (The red/Blue wire above the starter wire is one of the 2 neutral safety wires)

 

3 - The ENG fuse would blow when the ignition would turn on (The red wire at the bottom of the loom)

 

All sorted with some beer, frustration and some sailor speak.

 

Thank you for all the suggestions, very helpful.

 

Onto the next drama.....

[hendrixhc 10,918]

Nice work on finding the fault.

 

Dont you just love electrics!

[MNTL.XD 3,831]

Well done! What a bastard of a thing to find, a shit of a thing in a shit of a spot, i never would've guessed that one!!

[NZXD 2,328]

Good find, reminds me of lazy tradies putting nails and screws into walls and hitting water pipes and electrical because they were to lazy to check first. <br /><br />However some people are just unlucky and hit a water pipe. <br /><br />

[Jiminy Kriket 133]

Thanks guys, was a real pain to find that is for sure.

 

Done now though. We have owned that car for 3 years and it has only just now cut that 3rd wire. What a pain.