Well im not an expert yet in the supra or the 1jz but the clicking that you mention might be because your battery is low on juice. It happened in my matrix where the battery was between 9v and 10v, all i hear was clicking sounds when i turned the ignition. Everything else powered on but when i tried to start it, i heard clicking sounds from the engine bay and the lights dimming. Got a new battery and it started fine.
Damn! Go to start my car for the first time and starter won't kick on :(
- Thread starter MarkIII4Me
- Start date
I had the same problem and here is what solved it. First I took the starter relay out and swapped it with another one I had. Then I sprayed some electrical cleaner in the base of the relay. I installed the relay back in the base and then I unplugged the connector under the glove box which is the last connector before going to the starter and sprayed it with electrical cleaner and plugged it back up. These are the three things I did and have not had a problem since. My car was doing it regular too. When I checked the voltage it read 6 volts at the starter when it was acting up. Hope this helps.
Just because you are getting voltage to the starter solenoid doesn't mean you are getting the current threw the starter relay tips.
Just because you are getting voltage to the starter solenoid doesn't mean you are getting the current threw the starter relay tips.
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Yeah JJ I was reading about the relay mod people was doing and I knew that the wire was big enough going to the starter solenoid so I keep trouble shooting until I found the problem. My car is doing fine now. No problems.:icon_bigg
Nah, it's "old" wiring 
In some respects you got lucky. The problem usually (but not always) involves something else related to the relay but even if it's elsewhere oxidation is almost always involved. That's why I advocate electrical maintenance of the sort you did. At minimum connectors should be cycled when the opportunity presents itself.
I'll again point out these kinds of problems are easily resolved by measuring drop under load. There is simply no better way.
Btw your comment about voltage/current across a connection was as good as it gets. You should put it back.
In some respects you got lucky. The problem usually (but not always) involves something else related to the relay but even if it's elsewhere oxidation is almost always involved. That's why I advocate electrical maintenance of the sort you did. At minimum connectors should be cycled when the opportunity presents itself.
I'll again point out these kinds of problems are easily resolved by measuring drop under load. There is simply no better way.
Btw your comment about voltage/current across a connection was as good as it gets. You should put it back.
Ok. I will. I have ran into that many of times on relays. Sometimes relays or switches will show continuity but the tips won't allow the current threw. Also the connector that is under the glove box is on the output of the starter relay. Everyone needs to check that connector when having starting problems. That is the first thing that I look for when troubleshooting is to see if there is anything else inline after the starter relay goes in itself. I notice that connector on the print. Hope this helps somebody.
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Bravo to 89supracrazy. Finally someone investigated the starter circuit on the other side of the firewall!
89supracrazy;1644113 said:
That usually happens because, unless their contacts are gold or the housing is sealed and filled with inert gas (almost never found on cars), run-off-the-mill relays depend on the arc caused by make/break to prevent oxidation of their contact surfaces. It's the opposite of contact erosion and why contact material needs to be selected for the application and sized correctly to the load. Most people understand too small is bad but bigger is not better.
This is all good info on the starter circuit. I'm gonna be replacing everything in the circuit while the car is apart for the body work. Thought I had fixed this problem with a new starter earlier this year when the car was (briefly) driveable, but always wondered why the old starter still tested good after I removed it. Hadn't failed to start after the new one went in so I didn't think about it again, but I'm thinkin' about it now.
The starter plug from the relay wire looked very corroded inside (could just be old dirty dielectric grease). It'd be great if I could simply splice on a new plug and be in business.
MarkIII4Me;1644196 said:The starter plug from the relay wire looked very corroded inside (could just be old dirty dielectric grease). It'd be great if I could simply splice on a new plug and be in business.
Which plug are you talking about. The B1 plug in this diagram which is behind the glove box.
http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=29
You can try what you said but I would try the three steps I went threw that I posted. More than likely it is your starter relay, oxidation in the relay base, or try the plug that I posted which is the B1 plug behind the glove box. It is not hard to get too. You can do these three things less than 30 minutes. Get some electrical cleaner and spray inside the relay base, B1 plug, and the spades on the relay. Take your relay apart and clean the tips inside or go buy a new one. Good luck.
I noticed you said that you took the blk/wht from the neutral safety start switch and hook it to the clutch pedal. You need the black in this diagram hooked to your clutch pedal to pull in the starter relay. The two wires going to the neutral safety start switch should be cut and spliced together. You have your relay tips going threw your clutch switch. Not good. Take your leads off the clutch pedal and splice them together and see if it starts. Make sure your in neutral, it will jump forward if your in gear.
http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=038
I noticed you said that you took the blk/wht from the neutral safety start switch and hook it to the clutch pedal. You need the black in this diagram hooked to your clutch pedal to pull in the starter relay. The two wires going to the neutral safety start switch should be cut and spliced together. You have your relay tips going threw your clutch switch. Not good. Take your leads off the clutch pedal and splice them together and see if it starts. Make sure your in neutral, it will jump forward if your in gear.
http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=038
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I already have both wires going to the clutch pedal switch. Any reason why I can't have both wires (black wire and white wire from AT harness) going to the clutch switch? Doesn't it just complete the circuit as if both wires were spliced together in the first place? I'm confused. Wouldn't splicing them together only fix the issue only if there was something wrong with the clutch switch itself?
The relay is needed if you wish to retain either the starter alarm interlock or the clutch sw interlock. Both the alarm and the clutch switch are not designed to handle the high current from the starter motor solenoid, which is why that relay exists.
The famous relay mod is just a hack to fix the fact that the connectors and/or relay contacts behind the right kick-panel have high-resistance from corrosion or wear, and are dropping too much voltage to operate the starter solenoid. I have also seen the ignition switch contacts do the same thing and the alarm connector. As JJ said, cycle the connectors to scrape off corrosion.
Tie the black-white and black-blue wires together to bypass the NSW at the tranny connector. Don't insert the clutch sw in this loop.
The famous relay mod is just a hack to fix the fact that the connectors and/or relay contacts behind the right kick-panel have high-resistance from corrosion or wear, and are dropping too much voltage to operate the starter solenoid. I have also seen the ignition switch contacts do the same thing and the alarm connector. As JJ said, cycle the connectors to scrape off corrosion.
Tie the black-white and black-blue wires together to bypass the NSW at the tranny connector. Don't insert the clutch sw in this loop.
^ That is why. The clutch switch is designed to pull the relay coil in, which is very low amps. This is why alot of people are having trouble with their cars starting. You can't take a automatic car a simply put the neutral safety start switch wires on the clutch switch and think you have it right. It don't work that way. Follow my link I sent you and rewire it to match the print.
Awesomo! That should be easy enough.
How does this affect the fuel pump not coming on tho? I'm hoping that simply splicing the wires togther resolves all issues.
How does this affect the fuel pump not coming on tho? I'm hoping that simply splicing the wires togther resolves all issues.
Jumper FP to B+ in the diagnostic block to check pump operation.
Are you sure you weren't hearing the power antenna. The pump only runs when the engine is rotating in my experience.
Are you sure you weren't hearing the power antenna. The pump only runs when the engine is rotating in my experience.
The fuel pump does not kick on until you turn the key over. That is how Toyota designed it. What color wires is on the clutch switch if you take those leads off. You need the black wire in the diagram broke threw the clutch switch. If you take those leads off and splice them without breaking the black lead you can crank your car without the clutch pushed which could result in injury to somebody if it is not in neutral. Make sure you find that black lead and break it like I said. Good luck.
I have the black wire from the AT harness ran to one side of the clutch switch, and the white wire from the AT harness ran to the other side of the clutch switch. When I push in the clutch and turn the key to start I hear a loud "click" in the engine bay. I pulled the signal plug from the starter and pushed a wire deep into the plug and then ran the wire through the driver window to test for current from the cockpit. I grounded my voltmeter to the metal around the steering column and got no current when turning the key to ignition. However I got a full 12v reading when I pushed in the clutch. Doesn't this mean that everything is working fine and there's either a problem with the plug to the starter, the spade on the starter, or both?
I ran a power line to the starter spade from the battery and cranked it over many many times and I got to around 40psi of oil pressure. No rattles from the engine and only a small coolant leak from the thermostat housing fitting for the turbo inlet line (easily fixed with a couple of rotations). So I'm ready to get this thing moving already.
I ran a power line to the starter spade from the battery and cranked it over many many times and I got to around 40psi of oil pressure. No rattles from the engine and only a small coolant leak from the thermostat housing fitting for the turbo inlet line (easily fixed with a couple of rotations). So I'm ready to get this thing moving already.
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