my 94 4runner is having troubles starting when I drive it somewhere and let it sit for a short period of time. If it is sitting all night it starts right up so it has been a very frustrating issue. I have replaced the starter with a new one and the starting is much smoother but the problem is still here. I don't think it is the cables because of the excellent starting in when it has been sitting for a long time. I have checked the starter relay and it is clicking. When I turn the key I hear the relay click and a high pitched humming but nothing else happens. To start my truck I must turn on the lights before I turn the key (some sort of anti-theft device I assume) and I think the problem might be related to this or some sort of failure at high engine temp. I am completely lost on what to do. Does anyone have any suggestions? Thanks

 

I'v had this problem several times and fixed it the same way every time. The relay for your fuel pump (or some other relay) will lose and regain its connection as it heats up and cools down, for whatever reason. So im assuming that it still turns over when it wont start right? When it wont start, listen for the fuel pump noise coming from the tank when you turn the key to ON position, if you dont hear it then its probably that relay. You can buy a new relay or just wiggle it around if it wont start next time to regain connection.
It always used to annoy so much because it would always start if I let it sit overnight. Hope that helps, good luck.

 

That high pitch humming is his fuel pump coming on.

Turn the lights on? That's odd. You're having no issues while driving?

 

yeah there are no problems while driving. Does anyone know where to disconnect or bypass the headlight switch mechanism for starting the truck so that I might proceed on my process of elimination. thanks

 

I have never heard of this anti theft device. I t sounds like something a PO might have done..... Is the relay that is mounted to the starter clicking? or are you talking about a differnt relay?

 

The starter relay is clicking, but not much else happens

 

after hunting around for a few hours i found the device for the security headlight starting switch and i think i have fixed the problem by just disengaging it so my fingers are crossed that this is over. thanks for all the input!