VT SS blowing main fuse (SOLVED)

[Skylarking]

@vc commodore, helping forum members and some friendly discussion is why many of us are here, may be to also learn a thing or two on the journey.

But you seem to enjoy criticising or demeaning people whenever the opportunity (as you see it) arises. I’ve already said I may be wrong about whether a VT has a fusible link on the starter cable so how many cars I’ve worked or whether you’ve moved a battery into the boot isn’t the issue.

The issue is why the 60A main feasible link blows (and in part whether the wiring diagrams are 100% accurate and can be relied on for fault finding). One of either a wiring fault, alternator fault or starter fault is likely the culprit

If there is no fusible link/wire on the main starter cable, that’s just cost cutting by the manufacturer, not good engineering principles

 

[UTE042_NZ]

When main is replaced i can turn the key all the way except the last bit (When you start) if i do it doesnt make any noise or try and start it just blows the main fuse.

This makes me think there is likely to be a fault with the actual starter motor or its 12V circuit. From memory, not specifically Holden.

Haven't starter motors always had a direct cable to battery? Even with the old mechanical (pull) solenoids. Sticking 12 volts from a known good battery across the starter's poles was how we would test them (dead motors don't spin and if they vibrate they need bearings).

The starter motor has to pull a fair bit juice from of the battery, but only for a short time while starting. Putting a fuse in that circuit would be counter productive. So they would put a fuse in the switching circuit.

Modern solenoids have more electronic ways to fail and if a starter motor circuit shorts it might be feasible for 12V to attempt entry to the solenoid/circuit. You'd want to have a fuse blow then.

Modern solenoids also often enclose the direct access to the starter motor windings (via the poles) so it may not be possible to disconnect the starter motor 12V supply and try again without the starter. Even if the key would get key all the way including the last bit without blowing the fuse, it would only confirm that the starter motor has a fault. It won't tell you if the solenoid is also faulty or damaged.

I would probably end up taking the whole starter/solenoid unit to an auto electrician. Or the whole vehicle.

If it helps at all the previous owner told me before starting that need to “turn key 3 times to prime pump 3 times because its a v8” (owned a vy ss few years ago and never had to do this) and to make sure that i push the key hard into barrel to ensure that the part in the key rubs on the ignition ring.

Makes me think the last owner had some starting issues and when he crossed his fingers "this is what seemed to work".

 

[Trevor loves holden.]

The engine moves so cable which are connected to a component bolted to the motor also moves. There is also vibration that transfers to all cabling within vehile body as it drives down the road. Vibration and movement can and does abrade insulation which can cause a short to ground. If such shorts to ground occur on an unfused wire, it can then cause a fire within your vehicle, especially if the wire is always live

Regardless of whether the VT does or doesn't have a fusable link on the live stater cable, it's not good practice to not protect wiring. Having such cables protected with corregated plastic pipe are a supplement that helps to reduce risk but such should not be a full replacement for fusible links.

Oddly the VT workshop manual I have doesn’t have much info but the wiring remains much the same for engine wiring within VT2, VU, VX & VY. For those later doores, there is a bunch of fusible links and a fusible wire shown in the loom diagrams. Wiring diagrams I don’t seem to have

In any case, it would be more interesting to hear from @Benji_john93 as to what the problem turned out to be than debate fusible links/wires

Its just a matter of unplugging or unbolting one wire at a time until no more blowing fuses, very much doubt the alternator blowing the fuse when they have fusible links in line, which can only mean the starter motor going to ground. But we see, I hope they report back with the solution be very interesting what it was.

 

[axemurderer101]

Hey what would I know ive only been an auto sparky for 11 years lol

 

[VT2Commie]

I would say that the OP's starter motor and/or starter motor solenoid has failed OR the LOAD side of the starter relay wiring FROM the starter relay to the starter motor solenoid may have rubbed through somewhere and is earthing out.

 

[Vin999]

I would say that the OP's starter motor and/or starter motor solenoid has failed OR the LOAD side of the starter relay wiring FROM the starter relay to the starter motor solenoid may have rubbed through somewhere and is earthing out.

Yep I second that as the wiring from s/relay to the solenoid pole has power to it even if the ignition key is off..... and this wiring is the link through to the main 60A fuse.
Most of us have found out the hard way with knowing power is always on at the solenoid when we have worked under car and accident touched a metal tool across the poles/engine block plus checking starting with screw driver and other things when your working on your own

If the OP wanted to test solenoid, he can hook up a remote starter to it and after turning ignition key on to start only , hit the remote starter switch and see if it turns starter motor at all or blows the 60A. Might be rear fuel pump which is wired to ignition system/start as the OP mentioned what the previous owner did to ignition key/pump to start car.

 

[Vin999]

@vc commodore, helping forum members and some friendly discussion is why many of us are here, may be to also learn a thing or two on the journey.

But you seem to enjoy criticising or demeaning people whenever the opportunity (as you see it) arises. I’ve already said I may be wrong about whether a VT has a fusible link on the starter cable so how many cars I’ve worked or whether you’ve moved a battery into the boot isn’t the issue.

The issue is why the 60A main feasible link blows (and in part whether the wiring diagrams are 100% accurate and can be relied on for fault finding). One of either a wiring fault, alternator fault or starter fault is likely the culprit

If there is no fusible link/wire on the main starter cable, that’s just cost cutting by the manufacturer, not good engineering principles

the vt/vx battery cable to starter motor doesn't have 60A main fuse on it per say but technically the (solenoid part) of starter motor does have the link to starter relay/main engine/ignition fuse so you can say we all are correct. Also most times batteries placed in boots are associated with electric fuel pump/s and a fuseable link /circuit breakers /cut off switches are used to prevent catastrophes.

 

[Skylarking]

Hey what would I know I've only been an auto sparky for 11 years lol

Almost certainly plenty, though attendance in itself is never a guarantee of attained knowledge (if our schooling system is anything to go)

However you’re correct, though I though that it was acknowledged via my statement “if that’s the case, I’m wrong. But hey that wouldn’t be the first time”

As is, I’d think as a professional you’d recognise that an unfused circuit is more a manufacturer cost cutting activity rather than any form of best wiring practice. So I’d say it should be fused (my opinion)...

In any case, why not use your skills and provide some constructive help to the OP‘s issue of blowing his 60A main every time he attempts to start his car.

 

[axemurderer101]

As others have said disconnect the start signal wire off the solenoid and turn the key, if the fuse blows there is a short in the wiring and if it doesnt there could be a short to ground in the start solenoid.

 

[Benji_john93]

Alright guys so ive pulled the starter motor out today and checked it and its working fine? So i guess i need to check the alternator next and then go hunting for a dodgy wire somewhere?