ignition switch issues

[Hobbes992]

ok, my starter works fine. the problem is that the only way I get it enough juice is through a terrible ghetto made at home starter switch that hooks directly to the battery. The car is manual and because of the switch I'm able to bypass the starting with the clutch depressed which I guess is cool but... eh time to go back to the ye old key method. So I've been reading the tsrm and apparently it's going to be one of three issues.

1) An open circuit, which I doubt because the way I currently have the power going to the starter would be fucked seeing how I have it spliced into the line directly before it hits the solenoid.
2) faulty ignition switch
3) faulty clutch start switch
4) fusible links... wtf? Ok with the tsrm I've been able to locate the ignition switch and the clutch start switch but where the heck are these "fusible links" that supposedly run from the battery TO the ignition switch/ clutch start switch.

On a side note, interestingly enough there have been times when I've actually been able to crank the car using the key ignition after running it for a while, as though it couldn't be the fusible links because wouldn't that just outright kill all possible key ignition? So my plan is to test what I know first, but if any of you could tell me where the fusible links are I would REALLY appreciate it

Thanks!

 

[Hobbes992]

nobody?

 

[mrnickleye]

Problems like your are the kind that I'd need to be there looking at it.

I think the fusible links are ok, by what you've said.

Ignition switches go bad all the time.

At Carquest they are $153 list / $74 my cost.

Also check dealer, and some other parts stores.

 

[turbogate]

I'm having the same problem. From what I've heard, the cable that supplies the starter with power from the battery is by now old and internally corroded in many cases, therefore not supplying enough juice for the starter to get going. Thats why sometimes out of the blue it works, and most times not. Let me know if you find out the solution. I'm considering getting a purpose made starter push button and permanently doing that set-up.
Later

 

[Finnon]

is the solenoid just clicking? if so then theres a relay mod you could do. its written by a guy on the uk supra forum.

ill link it in a mo for u guys

btw my supra is a 1987 model and ive never had a problem with this. unless its been replaced at somepoint

 

[Finnon]

A common problem on Supras seems to be the Starter Solenoid not operating properly. The symptoms are a clicking noise when you turn the key, but no Starter Motor turning. Although this MAY be due to the Starter Motor/Solenoid needing an overhaul, poor design of the power feed to the Solenoid seems to cause problems - this modification is much easier than removing the Starter and is worthwhile doing anyway.

The lead to the solenoid performs 3 functions: It powers the Solenoid which pulls the starter gear teeth to mesh with the flywheel; It sends a small current through the Starter Motor so it turns slowly to assist meshing the gear teeth; Finally the Solenoid closes a big switch to allow full power to be applied to the Starter Motor (it draws about 200 Amps).

There are a number of design flaws with the feed to the Solenoid. Firstly, the wire is too thin for the amount of current drawn (so it will get hot and gradually corrode with age, causing its resistance to increase over the years). Secondly, unlike US Supras, UK cars don't seem to have a Relay to supply this feed, so it comes through the ignition switch. This also creates another problem, in that this wire then has to go through the Alarm to immobilise the car, adding another source of resistance (increasing with age).

I suggest a very simple modification which overcomes ALL these problems with minimum effort! Fit a Starter Relay, so that the Solenoid gets its power straight from the Battery - this relay can be powered by the existing Solenoid feed wire, as the relay takes a very small current to operate, any resistance problems become insignificant. This also means that the ignition switch and Immobiliser still work normally.

1. Buy a 12V Relay - best get an automotive one that is Plastic Encapsulated, with Spade connector terminals, and best with a mounting lug on the case.

2. Mount the relay on the Bulkhead on the Nearside of the engine - I found a spare 6mm tapped hole, so used this to mount the relay as well as provide the chassis connection.

3. Run a nice thick (20A) wire from the + side of the battery to one side of the Relay contacts - the other switch contact goes to the Starter Solenoid, so needs a standard Spade Connector on the end.

4. One side of the Relay coil goes to the chassis, the original Solenoid feed goes to the other side of the coil (the original spade connector should just push onto the relay terminal, if you mount it near enough)

Note: As with any work on the car, disconnect the battery first! I also soldered all the wires onto the Relay terminals and taped the whole load up with insulating tape, apart from the terminal for the original Solenoid feed spade connector to push on.

 

[Finnon]

there you go, copied and pasted from the uk site