fusible link keeps blowing / rebuilding loom

[urantia]

Have finished putting back together a celica st162 with rebuilt motor, it's all wired up. Whent to start it, but wouldn't kick over. (cranks but doesn't fire)

Checked the fuel pump first, completly dead no activity. Also no spark, Ok check also if the ECU was getting power, nope it was not. Check the EFi main relay was getting power and working and no it was not.

Had a look at a wiring diagram i found from a camry manual which i assume is very simular.

Looks like there are two fusible links that lead from the positive battery terminal to the ignition switch which then feeds power to all the things that were not working. Seeing as the startmotor was working fine the ingition switch was most likely not the problem. But everything on that AM2 fuse was not getting power it must mean that the fuse is blown. LOL yes yes it was blown, it was just hard to see.

So anyway i got another fuse and tried it again.. instant blown fuse, ok this isn't good.
So i procedded to unplug all the things that relied on this fuse which included all 4 fuel injectors, a few other things and the igniter assembly. This time i applied a blade type 30amp fuse becuase i ran out of the other type. Anyway i heard relays click so this was a good sign.

I proceeded to plug things back in and try apply igition to see if the fuse would blow, ended up with the igniter assembly last and plugged it in and the fuse didn't blow. So perhaps there is a bad connection in the plug with too much resistance cuasing too much current draw?

I managed to start the motor (sounded very bloody good for it's first start after my rebuild efforts)
Gave it a rev and the fuse blew - . I can only put this down to the extra current draw from the increased spark needed. But with a shitful connection it's trying to get thru.

Old crusty looms are a nightmare! Is there a way to renew the plugs on them? as in buy them brand new? i'm pretty sure this is the source of my issue, And while i could probably just clean up the connections on this old loom i'm bound to run into constant electrical problems. for example The injector plugs are only sitting on the injectors! nothing clamping them on due to there brittleness and missing chunks of plastic -

Also noticed 2 plugs near the battery area were so corroded and melted from battery acid that i was better off scraping the plugs and joining the wires with jaycar connectors.

Who has some leads with this sort of thing?

[river]

Hi,

If there's something there with too much resistance then the part/plug may get warm, but it shouldn't blow your fuse. However, if you have something with too little resistance - like a short or near short - then that can do it.

seeyuzz
river

[urantia]

Yes that makes more sense now that i think about it. Will have a better more detailed look at this tonight.
With the condition of these wires the insulation has probably broken away and allowed wires to touch eachother. Would pay top dollar for a new/near new loom! But how handy it would be to get the plugs to make it myself tho and just to replace the old brittle broken plugs.

[river]

Hi,

You can do the plugs yourself but you need to get the correct plugs and contacts for the plugs, then cut the wires, strip them and crimp on the new connectros and insert the connectors into the new plugs. Not hard stuff to do, but time consuming. Also there often isn't too much slack in auto looms so you need to make certain you have enough slack to be able to put non the new plug.

Furtheremore, it may not be the plug at all but something touching/shorting within the loom or somethign shorting out on the engine or car body.

It could be, as you mentioned, the current draw of the new stuff you put into the car. DO you have specs on the ignitors/coils atc that you added to see if it is more than the rated capscity for the fuse? Also, what else is on this fuse?

seeyuzz
river

[urantia]

Well if toyota would sell the correct plugs new on there own that would be fantastic. I'm I have no issues with taking the wires out of the old plugs complete with crimps still attached then slipping them into new plugs. Wouldn't have to cut any wire or worry about length issues. (but really depends on the wire condition too)

Yeah the fuse blowing issue may not have anything to do with the electrical plug connectors, but i feel uncomfortable having injector plugs sitting blowing in the wind due to broken clips. Just another source for a problem there.

Well the igniter and things running off that fuse are all stock, if they are in ok health they should not be rated above the fuse's rating which is 30amps. From memory the fuse provides power to all 4 injectors, the ECU, the ingniter assembly, the ciruit opening relay and possibly the coil and a few other bits. Which does sound like a heck of a lot for 30Amps. But yes i think your right in that the loom is touching/shorting out somewhere, hopefully externally and visible. Hate to have to untape that loom.

[thechuckster]

you could have wired up the alternator incorrectly? check that the Alt light isn't grounding out anywhere or is connected to the Ign point by accident.

If you're not getting enough voltage to the ignition, the Ignitor or coil will get warm.

[urantia]

Thanx chuck, i'll check that.

I found that its an intermittent issue, the igniter and coil had nothing to do with it as i previously thought. (as it worked when they were disconnected before, but not now.)