No start issue.

Compton74

Compton74

New Member
Oct 8, 2008
355
0
0
Long Beach
87 1jz car 5 speed
I'm used to the normal supra not starting issue, with the turning of the key the relay clicking and no start. Only reason I'm posting this is because the symptoms differ than the normal symptoms with the issue stated above. Car has been doing it at random. Get in to fire the car up, turn the key nothing at all. The car will toggle power like its supposed to, but will not even click the starter relay. Usually if I sit there for a while it will eventually start, but car has never had the issue in the 2 years I've owned it.

Things I've checked:
Starter relay: tested fine and worked fine
Ignition: tested fine, removed turbo timer and harness in order to remove any aftermarket interference
Clutch switch: took it off and bypassed, not positive if I did it correct. Unplugged switch and ran a jumper wire across both terminals on the plug on the harness side, but after bypass car still would not fire up
Any fuse regarding ignition all started fine

I honestly think its the clutch switch acting funky. If I am correct when the key is turned the only thing feeding power to the starter relay and starting system is the clutch switch. Any Input on the issue would be greatly appreciated. Thanks!
 
davidlkirby

davidlkirby

New Member
Sep 5, 2006
27
0
0
Chattanooga, Tennessee
When you say "starter relay", are you referring to this mod?

http://www.supramania.com/forums/sh...randomly-READ-THIS-(30-Amp-Starter-Relay-Mod)

If not, I highly suggest you do it. I drove my car for over a year with a signal wire that carried just enough volts to start the car 50% of the time the first try. If your starter doesn't click, I would suggest that your signal is too weak to even click it, much less click and turn the starter. I would probe your problem areas (starter, clutch switch) with a multimeter to find out how strong your signal is to the starter. Hopefully your issues are consistent enough to test this well. In my case, I had good days where I couldn't get the car to not start at all.
 
D

Dan_Gyoba

Turbo Swapper
Aug 9, 2007
1,836
0
0
Alberta
www.gyoba.com
@davidlkirby: You mean the mod that bypasses the starter relay with a relay? As it says in the title... read the whole thread. There is definitely a better way to fix that.

Take a look at the TEWD Page 38. Unless your car is a Canadian spec auto (Guessing it's neither Canadian, nor auto), the clutch start switch goes to the starter relay, which makes its ground through the theft deterrent computer. Maybe your theft deterrent computer thinks that you don't belong in the driver's seat, possibly caused by worn key switches. Maybe the starter interrupt relay is getting old, too. Weirder things have happened.

Option 1. Fix TDDS so that it arms and disarms properly when you lock/unlock the doors, or at least the starter interrupt relay closes when it disarms.

Option 2. Bypass TDDS starter disable. A short between pins 13 and 5 on the TDDS computer will bypass the starter disable function. You can try this first, and if it eliminates the problem, then you know for certain what's causing it. Personally, I'd fix the system, because if it isn't working, then it may do other flaky things to you, like honk the horn or flash the lights when you don't want it to. That's not the kind of attention that I want my car to attract when I'm driving it down the road. :D (It's academic to me anyway, since my Canadian car doesn't have the TDDS.)
 
Sside

Sside

Member
May 20, 2008
554
0
16
Houston
Do not do the "relay mod"..... Well, its your car you can do what you want but that's not a fix. Jet-Jock and others have clearly stated why. I too hated that nobody would give a straight up answer to why this happens. And then I stopped being lazy and started to diagnose my no start issue. I was on the verge of doing stupid relay "mod" but I couldn't will myself to do that to my car. Turns out its not a hard fix at all. Reason nobody can say exactly what it is is because its could be a couple of things but without actually taking a ohmmeter to that specific car and components it be very hard to say what it is exactly. If I were you thou I would take Don-Gyobia's advice and start by the alarm system. Pull that crap off completely. Its not gonna stop anyone from stealing you car anyways even if someone wanted to steal it.
 
Poodles

Poodles

I play with fire
Jul 22, 2006
16,757
0
0
42
Fort Worth, TX
Many people don't realize the starter solenoid is a giant relay, that's why the "rewire" always makes me laugh.

Not to mention if it's intermittent, it's the damn contacts in said relay (i.e. in the starter) It's a cheap fix but most mechanics these days are part swappers...
 
Compton74

Compton74

New Member
Oct 8, 2008
355
0
0
Long Beach
Honestly I put a start button in to fix the issue. Everything was receiving power and correct voltage so I thinks it's got to do with the security system, I will address it when my daily is out if the shop and I have time to put the supra under the knife.
 
3p141592654

3p141592654

90T
Oct 11, 2005
3,815
13
38
Thousand Oaks, CA
This circuit is so trivial everyone should be embarrassed if they cannot diagnose it.

Things to check in no particular order:

1) Starter (starter relay contacts wear out)
2) Ignition Switch (using voltage drop test under load)
3) Starter relay used for theft deterrent & clutch interlock functions (using voltage drop test under load)
4) Neutral Start Sw A/T only (using voltage drop test under load)

There's nothing else. Old wire, crack me up!
 
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