Hey guys! I have a 95 4runner that won't start on really hot days. When I turn the ignition I just hear a clicking noise from what I'm pretty sure is the starter. But if I get a jump start on these hot days it seems to work. Sorry if this is a repeat post I couldn't find the info on it. If this has happened to anybody I would like to know what you did to fix it and how effective it was. Thanks

 

Sure sounds like a weak battery. Put your voltmeter ON the battery, and have someone turn the key to STA (start). The battery voltage at rest should be around 12.6, with the key turned it should still be around 12.4 or more. If, instead, it drops to much less than that, it's the battery.

 

Oh I forgot to mention that the battery has been replaced multiple times and the problem still exists so it isn't the battery. That's what I thought at first too.

 

And this only happens when it's hot. For example if I drive for at least 1/2 hour in mids 80s or even if it sits in sun on 90+ days. This problem never happens when its cold. And when it happens on those hot days it usually starts back up after 30 min -2 hrs of rest depending on how hot it is.

 

Hmmm. You thought it was a weak battery at first. So you replaced it. Multiple times. I think I see a pattern here.

Your battery could be weak because it's worn out. Or it could be weak because it's not charged. So my advice is still the same. But this time, once you get it to start, the voltage should be around 14.1 at the battery. If it's less than, oh, 13.5 you've got a problem with the charging circuit. (CIRCUIT! Don't just run out and buy an alternator.)

There's no guarantee that this will immediately reveal the problem. You could have an oddly sticky solenoid, that is unusually temperature sensitive. It could be that it takes time to get your jump start, and in that time your solenoid cools ever so slightly, so jumping now works. But it sure sounds like a weak battery, and you haven't (yet) done the basic tests to rule that out.

Oh, no multimeter? No excuse for that! http://www.harborfreight.com/7-funct...ter-90899.html

 

But if the battery isn't charged enough or is too weak how come it starts with no delay after sitting for about an hour. And why only when it is hot? I am 100% convinced that the heat comes into play here because it has NEVER happened when cold.

 

Also the engine doesn't ever even turn over at all. Usually when I experience an undercharged battery (usually because I left the lights on or the radio was on for too long) on my other vehicles the engine at least attempts to crank. This has not happened once when I have this no start issue on the 4runner.

 

Like Scope103 said ^^^
If battery is good, symptoms are signs of things not making good contact.
I suggest you inspect and make sure connection from battery to starter relay to starter solenoid.

Certain connections may have high resistance. Resistance gets higher with temperature and allows less power to get to where it's needed.

Could also be due to starter solenoid contacts that are worn out and barely making good contact when closed.

High resistance from starter relay circuit will limit power going to solenoid coil so contacts may not close all the way, compounding the problem.

Try this to send battery power directly to starter solenoid coil. If it consistently starts your truck, suspect starter relay circuit/connections