1989 MkIII Supra often refuse to crank over when hot

[shipkiller]

I've been battling this issue recently with my mk3.
1jz 1989 with a R154.
It started to refuse to crank over randomly when the engine is warm/hot. At first it was rare but now it's almost everytime the engine is hot.
I redid the wiring harness last year, so i'm pretty confident the starter is triggered everytime I turn the key but the lights barely dims. I can hear the starter relay click.
I'm using the OEM starter power cable, battery has plenty of voltage (I even tried boosting it with another battery just to be sure).

It will crank over (and start) everytime when cold, no problems there.

Do I need to replace the starter motor? I want to be sure before pulling this thing.

thanks

 

[Enraged]

it's a simple thing, but check your grounds.

 

[tlo86]

its your starter, quite simply.

 

[shipkiller]

Replaced the starter, wasn't the starter.
I've mesure the trigger voltage when I put the key to crank position and I'm only getting 8-9V instead of the 12V+ (without the big cable connected so that the starter wont spin).
I might have to replace the trigger connector+wiring from the body harness connector to the starter.

 

[Enraged]

did you check your grounds?

 

[shipkiller]

I did, I also upgraded the grounds last year when I made the wiring harness. I have one on the block, head and intake manifold plus one chassis to neg battery directly

 

[Enraged]

maybe the starter relay?

http://www.mk3supra.org/topic/10-guide-start-relay-mod/

 

[Nick M]

Replaced the starter, wasn't the starter.

You beat the odds by a large amount. Heat soak 101.

I've mesure the trigger voltage when I put the key to crank position and I'm only getting 8-9V instead of the 12V+ (without the big cable connected so that the starter wont spin).

Heat soak. Heat increases resistance. On the old wires with corrosion on the inside that you don't see (assuming the posts are accurate) it is worse. It is dropping nearly 4 volts. Do the voltage drop test on both wires, especially the large one.

 

[tlo86]

oo man id like to see those wires ive seen some bad ones before...

 

[plaaya69]

I used to have that random problem with the starter just clicking when I first got my Supra in 2007 and in 2008 I did the starter relay mod. I never once had a starting problem since.

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

 

[Nick M]

More pie.

 

[jetjock]

^ Lmao...