My car has been intermittently refusing to start

LANGE17

MEMBER
1992 TOYOTA CAMRY
4 CYL
2WD
AUTOMATIC
190,000 MILES

For six months, my car has been intermittently refusing to start. There appears to be plenty of power, but when I turn the key, nothing happens. There is no clicking sound, no attempt to turn over, no noise of any kind, nothing. The lights don't dim and a jump start doesn't help, so my mechanic and I concluded that its not the battery or alternator. The mechanic has replaced the starter twice, but the problem keeps happening. Two weeks ago he replaced the entire steering wheel (as a means of replacing the ignition switch) but the problem recurred and I was stranded yet again.

It may be coincidence, but the problem seems to happen primarily after I've taken a trip of a mile or two, turned the car off, run a quick errand, and come shortly back to the car. For instance, the most recent occurrence occurred Friday night after a 5 minute drive for Chinese takeout and 5 minutes out of the car to actually get the food. The car refused to start when I got back in it, but Saturday morning I returned to pick it up and it started fine.

Update: I just tested that theory, and it seems it may be accurate. I hadn't started the car since Saturday, and it started this (Monday) morning just fine. I turned it off and started it again- no problem. I drove it around the block a couple times, returned to my driveway, turned it off, and it would not restart.

Any help would be very much appreciated as I'm already $600 in the hole on a car not worth appreciably more than that. Thanks!

9 Replies

KHLOW2008

MECHANIC
41,814 POSTS

Hi lange17,

Thank you for the donation.

From the description of the symptoms, I believe it is the starter circuit that is causing the problem and it can be due to :
1. Security system. If vehicle is equipped with security system, it could be malfunctioning and arming itself preventing the starter circuit from completing. It could be a fault with the starter cut relay.

2. Gear inhibitor switch. When problem occurs, did you try shifting to N and see if it works?

3. Starter circuit. It could be a malfunctioning relay. Check the relay located in Relay Box # 6, behind the glove box.

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Thursday, February 25th, 2021 AT 4:13 PM

LANGE17

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9 POSTS

I don't have any security system, at least that I'm aware of.

I had not tried starting in neutral. I just went out and experimented, and this is what happened:

Car in park
Trial #1- Didn't start
Trial #2- Didn't start
Car in Neutral
Trial #3- Didn't start
Trial #4- Didn't start, but I thought I heard a faint "click" like it was trying to start. I had never heard (or at least never noticed) this before- its always either started right up with no problems, or been totally unresponsive.
Car in Park
Trial #5- Started right up.
Trial #6- Started right up.

Does this make any sense? Does it support the gear inhibitor switch theory? Is it just a coincidence? Should I go ahead and try to test the relay (will take a day or two)?

Thanks so much for the help!

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Thursday, February 25th, 2021 AT 4:13 PM

LANGE17

MEMBER
9 POSTS

I just did another series of trials. Four times in a row, it would not start in park. Four times in a row, it started perfectly in neutral. I don't know what to make of the previous series of tests, but right now I'm happy to believe its narrowed down to the gear inhibitor switch. Should I do something further to diagnose? Can I further diagnose and/or fix on my own (basic skills but nothing more), or do I need to go to a (different) mechanic?

Thanks for helping me make some real progress on this!

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Thursday, February 25th, 2021 AT 4:13 PM

LANGE17

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9 POSTS

OK, one more response and then I'll wait for your reply. Is the gear inhibitor switch another name for the neutral safety switch? I did some sleuthing on your site and it looks like it may be. I went out and looked under the hood for the neutral safety switch, but couldn't find it. If I'm on the right track, help finding it would be much appreciated as well. I understand from your site that its likely front left, near the radiator. I'm attaching pictures in case you can see it and just tell me where to look.

Thanks!

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Thursday, February 25th, 2021 AT 4:13 PM

KHLOW2008

MECHANIC
41,814 POSTS

Sorry for the delay in getting back to you.

Yes, inhibitor is another name for the Neutral Start Switch.

The part is located at end of gear shift cable below the red circle in the diagram.

Neutral start switches seldom fails for both Park and Neutral at the same tme. If it is the cause, most probably it is due to bad wire connections. The location of the switch is low down so quite often water contamination would cause oxidation od the connections resulting in intermittent continuity.

The above data would enable you to test the switch.

You can test the starting circuit by using a jumper wire to bypass terminal 2 and 3. If cranking is still impossible, then it should not be the switch.

You mentioned hearing a clicking noise, that could be from the starter relay. Relay coil circuit coudl be good and working but the power circuit is bad not allowing voltage to be supplied to starter motor.

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Thursday, February 25th, 2021 AT 4:13 PM

LANGE17

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Thanks for the great assistance. I went to the mechanic this morning to demand a return of the $300 I paid for a new ignition switch. Of course, when I got there, the car magically started in park just like its supposed to. Still, armed with the knowledge you have imparted, I got him to agree to replace the neutral safety switch free of charge, and keep the $300 money-back guarantee in place if it should happen to still not be fixed. If I do have problems again, I'll be back.

Thanks for your help!

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Thursday, February 25th, 2021 AT 4:13 PM

KHLOW2008

MECHANIC
41,814 POSTS

You are welcomed and glad to be of service.

If it happens, don't forget to check the starter relay.

Btw when replacing the neutral start switch, check the wire harness terminal connector for contaminations and clean them. Apply some di electric grease to prevent water contamination which often is a cause for bad continuity.

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Thursday, February 25th, 2021 AT 4:13 PM

DEADHEAD111

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1 POST

Wondering if anyone could help me out im having the same problem. Pulled the electrical connector to switch and used a jumper wire to bypass terminal 2 and 3. Started up just fine as soon as this was done.

So anyone have a clue what the problem could be since it isnt the switch. Also wires didnt look too good going into the switch. Sheathing on several has been worn away and copper is exposed.

O and last question, is it possible to leave in the jumper cable until I get this problem fixed.

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Thursday, February 25th, 2021 AT 4:13 PM

KHLOW2008

MECHANIC
41,814 POSTS

The circuit in switch for starting is bad preventing the starter from being cranked.

This is circuit is a safety feature for preventing engine from being started when the gear shift is in not in P or N. By bypassing the circuit, the engine can be started in any position of the gear shift and if it is in gear, starting the engine can cause accidents as the vehicle would surge forward or backwards depending on the gear you are in.

Reconnect the switch and if you can start in N position, then use it to start instead of being in P. That would be a safer option.

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Thursday, February 25th, 2021 AT 4:13 PM