30amp engine bay fuse keeps blowing

[Cro]

Anyone any idea what this fuse controls? It keeps blowing everytime I start the car and try and drive off, seems to have some electrical current going through it when the keys arent even in the car, it sparks when a new fuse is put in and then blows on drive off.

Any ideas??

 

[bmh.01]

The bigger or one of the smaller one?

The big one is for the fan and the other one is the ecu.

 

[Cro]

bmh to the rescue again, it's the smaller one so ecu then. Why would it keep blowing, and can't be too good if the ecu is shorting somewhere

 

[bmh.01]

Pass, usual checking for shorts really. Doesn't supply the actual ecu, its powering the fuel pump, injectors, coil pack, etc so check everything really.

 

[Cro]

Hmmm loads of fun then, cheers mate i'll start checking everything

 

[Mike@Rentech]

Check the oxygen sensor wiring has not come loose and shorted out on the exhaust manifold, had couple like this in work.

 

[Cro]

Cheers Mike i'll give that a jeff too. Whenever I go to replace the fuse after one blowing it sparks a bit and one of the black and brown box things, which i presume are relays, click.
Is that normal? Any idea what these relays are for, if they are connected and could it be possible they might be faulty and causing this?

 

[bmh.01]

They're the injector lock and fuel pump relay, they're what turns the power on to everything engine management related when you turn the key.

 

[Cro]

Sounds like something might be constantly getting power if its doing that when theres no key in and the fuse is causing a bit of sparking?

 

[barnesautos]

Try checking the relays first ,might be stuck on, make sure they are not causing the short circuit had a few of them at work

 

[Mash84]

Check the oxygen sensor wiring has not come loose and shorted out on the exhaust manifold, had couple like this in work.

Over ten years later and this suggestion has just saved me a lot of head scratching and chasing wires! Unfortunately for me the wires were melted on the wiring loom side on the connector so I couldn’t just replace the sensor.