I'm at my wit's end here with this starting issue. Some days it'll start just fine, other days I get nothing but the starter relay clicking on and off. If I turn the key 10-20 times, sometimes it starts, other times like today I get nothing.

Starter's been replaced, found a broken solenoid contact in the old one and the issue seemed to go away for a bit.

Issue occurred the other day so I disconnected the quite corroded terminals to the battery and reconnected them, cleaning them up a bit in the process, and it started right up.

And here I am today. I've got no idea where to look next. The relay seems to click on and off reliably. The battery's got plenty of charge (lights inside and headlights are nice and bright.

What ground points should I check? Are there ground straps maybe or anything under the engine? The relay ticking over makes me think not relay or ignition, but I'm out of things to check...

... and it looks like I'm working from home today.

Had a thought to put it in neutral, started right up...

Have no idea if this is the solution though.

The devil is in the details. What type/brand was the replacement starter?

An OEM (or Denso reman) starter is the only reliable option.

-Charlie

I think intermittent issues point to a cable/ground problem.

For what it's worth, I have an intermittent start issue that is definitely my cable. My starter solenoids were worn and I rebuilt my OEM starter, and also rebuilt my alternator, both of which needed to happen.

The positive cable had a bunch of corrosion, which I cleaned, and it did absolutely nothing, but every time it happens I move the cable around and it starts up just fine. I'm going to chase down the connections and see if there's a loose ground somewhere over the weekend.

Batteries and starters are pretty easy to diagnose, if the starter was the issue, I would think it would get progressively worse and in a linear fashion, same with battery, intermittent or streaky issues usually make me think something is getting jiggled about. When the starter solenoids wear out, you'll get a delay when you turn the key to when it starts cranking. Batteries, or charging issues usually present as slightly slower cranking speed, suggesting you're not quite getting the amps you normally do.

That said, if it's a switch issue (and I have no idea where or how the switch operates for P vs. N on these Runners) - switches are usually pretty easy and cheap to just replace.

If you have a test light see if you are getting power to the starter. It sounds like an intermittent wire or bad ground but if the neutral switch is no bueno, then that definitely could be the problem.

Keep starting the 4Runner in neutral and see if the problem manifests itself again.

3x instances of no-start on key-turn.
- 1x super rainy day, no start on key-turn, put in neutral and started right up
- 1x later that day for the drive home, no start on key-turn, put in neutral and started right up
- 1x the next day, no start on first key-turn, instinctively tried 3x more in rapid succession, started on last key turn

It's that last behavior that's just confusing.

It's also worth noting that I had a separate issue on the first day. I need to clean the throttle body and this vehicle has an aftermarket cold air intake and throttle body spacer. I have had a theory that when it's cold, the long tube for the aftermarket air intake has a low spot that condensation builds up in. The issue is that it runs extremely rough, no power (barely or no forward movement), and popping from somewhere intake/exhaust side of the engine bay. My theory is that it sucks through a bit of water which prevents combustion (misfires). The issue went away after a timing belt and tuneup last year, but it hasn't been faced with wet and cold really (not NH winter wet and cold at least since I moved to WA). It's a very weird intermittent issue that I might just open up a separate thread on .

Still need an answer to this.

This could be a dirty neutral safety switch or bad starter contacts - or, if a bad quality starter was used last time, another issue with the starter.

-Charlie

I'm really not sure how that's relevant given the behavior. I am not sure what was put in, I believe it was a Denso, but it was put in by a come-to-your-vehicle mechanic and I didn't see/keep the box. I can think of a lot of ways a new starter could fail, but none of it would result in intermittent failure to start where behavior is either a clean and normal start or no action at all (no sound/motion of any kind) with nothing in between.

Neutral safety switch is almost certainly the point of failure. Issues present with far greater frequency as ambient humidity increases, likely a short in switch or wiring to switch. Have been able to reliably reproduce behavior since where start in Neutral works just fine but Park does not.

This is good to hear. If you can do the work yourself, this is a nearly free fix... Remove the neutral safety switch on the side of the trans, open up, clean, put in new dielectric grease and reassemble/install.

-Charlie

I’m having the same issue, sometimes starts and sometimes it doesn’t. Starts in neutral. Did you find a solution?

If it always starts in neutral, clean (and re-grease) the neutral safety switch on the side of the trans...

-Charlie

So sometimes it doesn’t always start in neutral, but gets started after a few try’s. I’ll clean the safety switch, but how would I re grease it?

Plenty of guides out there. The A340x transmission was in a lot of Toyotas. Here's one, I'm sure you can find more:

DIY - Neutral Safety Switch (NSS) A340E 1987 - Toyota Nation Forum : Toyota Car and Truck Forums

(obviously ignore the parts about how to remove it - it is MUCH easier on the 4Runner)

-Charlie