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Old 05-30-2008, 09:13 PM   #1
Bill UK
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When you say it doesn’t start, do you mean the engine turns over but doesn’t fire up, or the starter doesn’t turn and just makes a clicking sound.? If it’s the latter and Gosport is in the UK, then is more than likely it will be the thin wire going to the starter . The UK supras don’t have a relay, the wire from the ignition goes straight to the starter solenoid (or via an alarm if fitted or neutral switch on an auto), one of the problems is the gauge of the wire, although probably ok when new, it is too thin and over the years the copper wire deteriorates, resistance increases due to age and the constant heat changes. This becomes more apparent when the engine bay heats up, the thin wire will also heat up, causing high resistance. A permanent fix is to fit a 30 or 40amp 12v relay in the engine compartment. Instructions below.
The thin wire from the ignition activates the coil in the relay which doesn’t need a lot of current. The switching part of the relay takes care of the amps required for the starter solenoid, The large wire going to the starter motor from the battery is the main power to turn over the starter motor once the solenoid is activated, this wire doesn’t need to be upgraded.
Insructions;
1. Disconnect the battery
2. Fix the relay to the bulkhead or somewhere covenant.
3. Remove the thin wire going to the starter motor and connect it to terminal # 86 on the new relay
4.Connect terminal # 85 to earth (negative) using a 20 amp wire
At this stage you can check the relay is working by connecting the battery
and switching on the ignition as you would normally do to start the car. You should hear a click from the new relay but the starter will not turn over until you have competed the next steps.
5. Remember to disconnect the battery again
6. Connect a 20 amp wire to the spade terminal on the starter motor. (This is where the thin wire was once connected.) Connect the other end to # 87 on the relay.
7. Connect 20 amp wire straight to the battery and to # 30. connector on the relay. Job Done.
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Old 05-30-2008, 09:36 PM   #2
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Try this first; connect a wire (about 20 amp) to the small spade connector on the starter motor, there are only two wires going to the starter, (both are positive) one large red wire which is bolted on to the starter and one thin one that is connected to a brown shielded spade connector. The other end of the wire temporally insulate, you may find it easer to leave the existing small wire connected and just crimp or solder the extra wire as close as possible to where it connects to the starter. Turn on the ignition (make sure its not in gear) remove the temporary insulation from the new wire and touch the positive terminal on the battery. If it does start then its more than likely the small wire has deteriorated. I had the same problem but didn’t have time to fit the relay, so I connected a wire to the starter and insulated the other end. On the odd occasion when the starter just made a clicking sound, I just popped the bonnet (hood if you live in the US ) removed the insulation from the new wire and touched the positive terminal on the battery and up she started. I eventually got around to fitting a relay.
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Old 05-30-2008, 10:06 PM   #3
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This is the one I fitted igosaur 40A SPNO Auto 12Vdc N02AW Maplin
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Old 05-31-2008, 08:22 AM   #4
igosaur
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Yes, I am in the U.K.

Nothing actually happens at all.. Maybe there is a slight click sound but other than that, nothing.

Thanks for the instructions, this will certainly give me something to do over the weekend
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Old 08-28-2010, 12:04 AM   #5
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Quote:
Originally Posted by Bill UK View Post
When you say it doesn’t start, do you mean the engine turns over but doesn’t fire up, or the starter doesn’t turn and just makes a clicking sound.? If it’s the latter and Gosport is in the UK, then is more than likely it will be the thin wire going to the starter . The UK supras don’t have a relay, the wire from the ignition goes straight to the starter solenoid (or via an alarm if fitted or neutral switch on an auto), one of the problems is the gauge of the wire, although probably ok when new, it is too thin and over the years the copper wire deteriorates, resistance increases due to age and the constant heat changes. This becomes more apparent when the engine bay heats up, the thin wire will also heat up, causing high resistance. A permanent fix is to fit a 30 or 40amp 12v relay in the engine compartment. Instructions below.
The thin wire from the ignition activates the coil in the relay which doesn’t need a lot of current. The switching part of the relay takes care of the amps required for the starter solenoid, The large wire going to the starter motor from the battery is the main power to turn over the starter motor once the solenoid is activated, this wire doesn’t need to be upgraded.
Insructions;
1. Disconnect the battery
2. Fix the relay to the bulkhead or somewhere covenant.
3. Remove the thin wire going to the starter motor and connect it to terminal # 86 on the new relay
4.Connect terminal # 85 to earth (negative) using a 20 amp wire
At this stage you can check the relay is working by connecting the battery
and switching on the ignition as you would normally do to start the car. You should hear a click from the new relay but the starter will not turn over until you have competed the next steps.
5. Remember to disconnect the battery again
6. Connect a 20 amp wire to the spade terminal on the starter motor. (This is where the thin wire was once connected.) Connect the other end to # 87 on the relay.
7. Connect 20 amp wire straight to the battery and to # 30. connector on the relay. Job Done.
This fix works perfectly! Sorry to bump such an old thread but I've been able to resurrect my 86.5 N/A and I had to join the forum just to say thanks.

For anyone else with this issue, here is the kit I used.



http://www.amazon.com/Dorman-85937-S.../dp/B0024GM6HI
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Old 08-28-2010, 01:40 AM   #6
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naw thanks for bumping it otherwise i never would of seen it.
moving to the faq.
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Old 02-07-2019, 07:09 PM   #7
11Ton Butterfly
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Thanks for this!
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