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86 Toyota Supra N/A
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Discussion Starter #1
Hello everyone,

I've been having some issues starting my N/A 86 Auto Supra. The car has had an off and on start history while I've owned it and seems to start when it feels like it (It started when I bought it but later wouldn't start. Then a week later started, and now doesn't start.)

At first I though it could be the battery or alternator but I had those checked and the alternator charger fine and the battery is currently at 90% charge. So the logical move would be to check the starter, so I took it off and noticed it was definitely funky so I replaced it with a new one the next day. Hoping that fixed the issue I tried to start the car, but nothing happened, no clicks or sounds or anything.

So I did some research on Supra forums and found it could have been the factory alarm or not enough power/voltage to the starter, however the starter definitely has power (I checked it), and I even spliced into the brown negative wire from the starter and hooked it up straight to the battery and turned the key to on and start. Still no start.

I am very confused about the whole alarm issue, and Im leaning to it being the problem but I have already tried the passenger door/ trunk trick, and even disconnected the battery to reset the Anti Thief computer to no avail. All I know is that the alarm light does not flash when I lock either door, but that could be just a bulb, I don't know. I also don' know if the previous owner messed with the alarm or anything, but it has never gone off so I believe the door sensors work? (I haven't tone apart the door panels yet).

Any help would be awesome!
 

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1987 MA71 R154 Pearl White, Blue Velour
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As I recall on my 87, the only way to set the factory alarm was to lock the door from the inside, and then hold the handle open when you shut the door. Interestingly mine doesn't even seem to arm anymore, I need to check that. :)

I would start with fuses, and relay's etc. I was doing some LED tail light conversion work earlier this year. Everything was working, and then all of a sudden my brake lights weren't. I had checked the fuse maybe 10 minutes earlier and somehow convinced myself the fuse was still fine. It wasn't, and I wasted a good amount of time tracking it down before I checked the fuse again and realized it had blown. *sigh

I highly recommend you get one of these. It will make your life MUCH easier:

 

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86 Toyota Supra N/A
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Discussion Starter #3
Ok sounds good! I tried the whole Starter Relay Mod today, talked about a lot in this forum, but it did nothing, which made sense since it really only fixes the clicking issue of the starter not getting enough amps or something due to crappy wiring.

I ordered the book, hopefully I can find the culprit soon, but if you have any more ideas of the possible problem, feel free to list them!

Edit: I did find a blown 10a fuse next to the starter relay on P-side kick panel, but i have no idea what it goes to? Anyway its replaced now but i'm little curious
 

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I did find a blown 10a fuse next to the starter relay on P-side kick panel, but i have no idea what it goes to?
A/C amplifier/ A/C compressor clutch fuse.

IF you have a multi meter and a helper, start by unplugging the solenoid wire from the starter and checking it for voltage when you turn the ignition key to crank. No voltage there? Backtrack to the neutral start switch and make sure it shows continuity between the black/white and black/blue wires when in neutral or park.

If your neutral switch checks out, move on to the starter relay. Sometimes the contacts in the relays will foul up and the relay will "click" but not transmit power. It's been a while since I've messed with the starter relay but I believe it's the same as the horn relay over in the left kick panel. You can try swapping that over to the starter relay position and see if that makes a difference.

For the theft deterrent system you might consider bypassing the system to rule it out. I think the wire you're looking for is going to be the blue/orange wire on the TDS, but you may need to trace it to the starter relay to be sure. If that's the right wire, just jump it to ground and that'll bypass the alarms interference in the starting system.
 

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Discussion Starter #5
A/C amplifier/ A/C compressor clutch fuse.

IF you have a multi meter and a helper, start by unplugging the solenoid wire from the starter and checking it for voltage when you turn the ignition key to crank. No voltage there? Backtrack to the neutral start switch and make sure it shows continuity between the black/white and black/blue wires when in neutral or park.

If your neutral switch checks out, move on to the starter relay. Sometimes the contacts in the relays will foul up and the relay will "click" but not transmit power. It's been a while since I've messed with the starter relay but I believe it's the same as the horn relay over in the left kick panel. You can try swapping that over to the starter relay position and see if that makes a difference.

For the theft deterrent system you might consider bypassing the system to rule it out. I think the wire you're looking for is going to be the blue/orange wire on the TDS, but you may need to trace it to the starter relay to be sure. If that's the right wire, just jump it to ground and that'll bypass the alarms interference in the starting system.
Ok great! I'll poke around next weekend with a multi meter and try rule out some more things. I'll get back to you guys soon with hopefully some good results.
 

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Discussion Starter #6
Just an update: I noticed the battery light active on my dash, and furthermore, the voltage meter doesn't drop 12V when I try to start the car. This definitely points to the battery being funky, but my dad doesn't believe so as we just replaced it (previous owner put the wrong size battery). Also my voltage meter seems to be weird as well because when I was driving the car, whenever I used the turn signal the meter dropped heavily. The clock also goes off when I try to start.

Hopefully thats helpful information. I'll do more investigating this weekend!
 

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If your alternator isn't charging the battery the battery light will be on, so if the car isn't running the light will be on. The clock usually shuts off when cranking so I wouldn't worry about that too much.

The voltmeter issue may be a bad connection in the cluster so I'd test voltage with the motor running using a multimeter to know whats going on.
 

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Just an update: I noticed the battery light active on my dash, and furthermore, the voltage meter doesn't drop 12V when I try to start the car. This definitely points to the battery being funky, but my dad doesn't believe so as we just replaced it (previous owner put the wrong size battery). Also my voltage meter seems to be weird as well because when I was driving the car, whenever I used the turn signal the meter dropped heavily. The clock also goes off when I try to start.

Hopefully thats helpful information. I'll do more investigating this weekend!
that is actually normal for the voltage drop due to the amount of current the starter pulls (OEM starter is rated at 1400 watts) which at 13.8v you are looking at 101 AMPS being pulled. This of course is steady state and does not include the startup current which usually is 4x that amount for a very brief period of time (around 1 second).

Is you battery in the OEM location in the front left side of the car?
 

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Discussion Starter #9
that is actually normal for the voltage drop due to the amount of current the starter pulls (OEM starter is rated at 1400 watts) which at 13.8v you are looking at 101 AMPS being pulled. This of course is steady state and does not include the startup current which usually is 4x that amount for a very brief period of time (around 1 second).

Is you battery in the OEM location in the front left side of the car?
Yes, my battery is in the OEM location.
 

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Verify your grounds and check your wire to the starter.
 
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Can you verify you have both the positive cable & cable going to your battery since you changed it? I was doing valve cover work on my car outside last year after it got dark and in a hurry I missed putting on the starter cable at the battery. Sounds silly i know, but when i first sat down in the car and tried to start it....silence. I was tired and went to bed, stressed out that maybe I had blown some circuit but couldn't even think of what.

I went out the next morning, moved the battery and there it was! Ugh, I connected it and all was well.
 

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Discussion Starter #12
Can you verify you have both the positive cable & cable going to your battery since you changed it? I was doing valve cover work on my car outside last year after it got dark and in a hurry I missed putting on the starter cable at the battery. Sounds silly i know, but when i first sat down in the car and tried to start it....silence. I was tired and went to bed, stressed out that maybe I had blown some circuit but couldn't even think of what.

I went out the next morning, moved the battery and there it was! Ugh, I connected it and all was well.
I'll check, I wasn't the one who replaced my battery (My dad did, I was gone), so he could have missed it. I'll update you on the weekend since I'm unable to see the car right now.
 

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Discussion Starter #13
Ok good news guys, I redid all of my grounds connections from the battery because they were definitely not making good contact. After that, I tried to start the car again and heard a loud click come from the ECT box (or around that's area).

I know I've seen ways to fix that so if you could tell me or redirect me to the post that would be awesome!
 

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Check the fuel pump relay in the fuse box behind the battery. When I had one going out it wouldn't crank if the engine was warmed up and had sat for about 20 minutes. It's common relay used in several places around the car. Another possibility is within the starter. The solenoid contacts and the copper ring that makes contact when you turn the key can become worn. A simple way to test this is to run a bypass switch to the starter solenoid from the battery. Be careful not to accidentally ground and use a thumb plunger type switch with the alligator clips on either end.
 

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Discussion Starter #15
Good news everybody, She Starts!! Turns out basically alot of the wiring is cooked due to the crappy wiring Toyota used and the extreme heat. So I redid the starter wiring and it fired right up. Next step is to redo all of the wiring. Thanks for everyone's help!
 

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For what it's worth, Toyota used some fairly high quality materials for the time the cars were developed. However, exposure can ruin even the most robust of materials, given enough time. Even the newest Mk3 out there is 28+ years old at this point.

Bit of advice from somebody who has learned the hard way to do wiring jobs correctly? Buy yourself a decent crimper. I have a ratcheting style one from I think Klein. Makes wiring jobs SO much nicer now... Second bit of advice, make sure that the type of wire you are using is appropriate for where you're putting it. That has bitten me in the rear a time or two!
 
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