No power to starter

[Holmsey]

Hi All, if the ECU don't see 12v, will the ecu not send power to the starter?
My 1UZ motor thats in my old pickup starts first crack every morning. But every now now and then there is no power sent to the starter, its totally dead. All the lights, fuel pump etc etc are working ok, there is just no power to the starter, not even a click or a slow turn over, dead totally. Ive changed the relay no cure, volt meter only showing 10v but 12.5v at my battery.
It usually does it when I drive somewhere and stop, when I come back to it its dead, leave it a while sometimes ages and whamm its starts right up? Runs a treat?

 

[numbchux]

On my '94 SC400 engine, the start circuit is very simple, ECU is not involved.

Where are you reading 10v? Sounds like you've got a voltage drop. When you test that, move your ground reference right to the battery and see if the voltage jumps up, that'll isolate which side of the circuit is your problem.

 

[Holmsey]

It's the voltmeter gauge on my dash showing 10v. Tests 12.5 at my ignition switch input, but only 10v to every other terminal on my ignition switch. Ive changed the switch but its the same. My next step (though I have no idea what I am doing) is to pull out fuses and see if the voltmeter shows 12v. I will try the earth straight to battery first, but it does sound like something is causing the voltage drop. Its just finding what. I will also try a different battery. oh and see if voltage drops at battery when I turn on ignition.. Its all black magic!! ;o)

 

[Holmsey]

If there isn't anything built into the ECU that would cut off power to the starter. Must be the neutral safety switch. I used it yesterday and started everytime no problem and voltmeter was still saying 10 - 11v, hard to trace a fault when it is intermittent.. Doing me nut in!!!

 

[numbchux]

Sounds to me like worn contacts in the solenoid on the starter...

 

[Holmsey]

Ok Cheers. Is this a seperate part, or is it a new complete starter?

 

[numbchux]

Ok Cheers. Is this a seperate part, or is it a new complete starter?

Part of the starter, would be included with a new one. Can be repaired/replaced separately, although I wouldn't do your first on a 1UZ.

 

[Holmsey]

I will just fit a complete new one, should of done it when I had the motor in bits.. Oh well Ha Ha... More work.

 

[numbchux]

Triple check all your contacts for that circuit. Main battery positive and ground cables, as well as the signal side (through the key and neutral switch). But the fact that it's drawing amperage makes me suspect the solenoid is activating, but the contacts are too dirty for the motor to turn.

This would be the stereotypical time to smack the starter with a wood block.

 

[gnc]

i hah the clip on the starter break ( old with the heat i suppose ) i replaced the starter and put a second feed to it on a starter button. not the easiest of jobs.