Does anyone have an idea of why my starter won’t engage when I turn the ignition key on?
This only happens occasionally after I’ve been driving awhile and shut the engine off and try to start it again after a short while, usually on warmer days. It will start eventually after a 5 minutes wait. I have already replaced the starter and this was no help. There are no sounds when I turn the key on. I was thinking of maybe replacing the ignition switch or the starter relay next, but I couldn’t find the location of the starter relay. The service manual says it should be in the Junction Block no.1 item A, but when I go to look for it, it doesn’t seem to be there! Do I even have a starter relay in that location??? Appreciate any help or suggestions!

 

What you are describing sounds like an excessive voltage drop problem. In this type of situation you need to reduce your voltage drop. There are two areas to look at. One is your overall voltage drop which would be your battery and your battery cables. If you are using clamp on battery terminals, that could be a problem. There could be a poor connection (corrosion) at either end of your cables. The second area of concern is the voltage drop on the starter circuit. You can research your particular wiring for your vehicle and "Hotshot Plus" relay. You may not actually need the Hotshot Plus. You can make your own or install a "Bump" switch under the hood. A Bump switch is relatively safe if you have an automatic transmission. I made one using a universal horn button switch. I have to plug mine in to use it, which is an additional safety feature. You don't want to have the switch in a position where you could accidentally press it while working on your vehicle.

 

If it's a manual, check the clutch start safety switch mounted at the top and directly behind the clutch pedal. There is a rubber grommet on the clutch pedal that can deform over time and maybe not fully engage to allow the truck to start. Nothing will happen. Why that might be could be while driving and depressing the clutch it moves about. Mine was completely flattened after 34 years and the engine would not start. You can but them on Ebay. They are a pain to put in as the flange end is way bigger than the mounting hole. Lube it.

Just one thing to check.

 

Toyota components are bullet-proof. It's often bad wiring that causes problems.

There is no starter relay on the automatic trucks, same as on 22RE's. The current needed to energize the starter solenoid goes over a looong path, causing lots of voltage drop. See below.


START by checking if your starter solenoid CONSISTENTLY works when you apply 12V directly from battery to its control pin as shown on my post here:
https://www.yotatech.com/forums/f199...l#post52367443

Then let us know. Details of that issue and fixes are here: https://www.yotatech.com/forums/f116...runner-307493/

Keyword: clicknocrank

 

Thank you Chuck and Joe for your suggestions!
I have an automatic transmission so the clutch start safety switch does not apply. As far as the starter relay location, I hear that there is none for automatics, only for M/T. After digging deeper into the service manual, it suggests that the no crank condition could be caused by a faulty ignition switch or a bad neutral start switch for A/T. Someone in another post suggested to measure the resistance of the ignition switch contacts when turning on the key switch. Also some people experience an intermittent neutral start switch which may explain why I may have to wait 5-10 minutes after engine cool down for it to work again on warmer days; that neutral switch is mounted on the side of the transmission close to the hot engine and exhaust. This reminds me that On a few occasions, after I started the engine and tried to shift to gear, the shifter would be locked in the park position and I couldn’t move the shifter until I pressed the override button on the console. I’m wondering if these 2 problems are both related to the neutral start switch. I will look into the ignition switch and the neutral start switch soon, and also try to research the Hot Shot relay solution that Chuck mentioned. The battery connections look very clean but I’ll have to have a closer look at the starter connections.
Thanks again for your suggestions!!

 

$30 "Hot Shot"

, as mentioned in my post:

 

Thanks RAD for all of the detailed information. Does this mod pertain to my problem of a No Click, No Crank condition on my 6 cylinder engine? This problem only happens occasionally, especially on warmer days, but it never fails to start if I wait a few minutes to try again. I’m planning on measuring the resistance on my ignition switch soon to try to isolate the problem.

 

Yup. . All explained on my post

 

In case anyone has starter issues with clicking, and it's the solenoid, it may be worth a look, before replacing the starter motor. The starter solenoid on my wife's '98 4Runner went out. I pulled the solenoid apart, and replaced ~$15 of contact parts. Simple job, and that starter continued to work perfectly, until the truck was totaled some 6 years later. It was surprising how good the internals looked in the original starter motor, given the age of the truck at the time

 

This, too.

 

Thank you Tacotex, In my case, I get no sound at all when turning the key several times on hotter days. But it will start eventually, usually within 10 minutes of trying over and over. At other times, I would get a delayed crank, like a half second to 1 second. I’ve had this problem for several years now. I have already replaced the contacts on the original starter with no help. Then I replaced the original starter with one from Napa Auto, and that was no help either. That’s why I’m looking elsewhere.

 

This does not sound like the issue Rad4Runner has so carefully documented. In my '94, the starting relay is in Relay Block 2 (under the hood) as shown in this '93 FSM: http://web.archive.org/web/201204170.../2powersou.pdf If you have the relay, don't replace it. (Replacing the starter that way didn't help much, did it.) Instead, it's very easy to test. The pinout should be silk-screened onto the top of the relay. These pix show you how to jump-out the relay and see if the starter (and solenoid) works. https://www.yotatech.com/forums/f116...switch-287859/

My guess is you have a bad (weak) ignition switch. Again, not so tough to test with your multimeter. http://web.archive.org/web/201102052.../3ignition.pdf The part is expensive enough that it's worth being certain in your diagnosis. https://parts.lakelandtoyota.com/p/T...445035080.html

 

I Repeat: Auto trans does not have a starter relay.

Toyota components are bullet-proof. Problems are often caused by poor wiring or poor maintenance.

I repeat: there is too much power loss because of the unnecesarily long path power to starter solenoid has to take (maybe 15 feet) - including possibly dirty NS9S contact and pitted/old ST1 contact of ignition switch, whereas with properly wired starter relay power travels only for a couple of feet - batt to starter relay - to starter solenoid. Therefore, the starter solenoid either does not clunk or if it clunks it does not do it energetically so solenoid contacts do not completely close, causing sluggish cranking.

A/T WITHOUT STARTER RELAY


PROPERLY-WIRED WITH STARTER RELAY

I repeat: test the starter solenoid by directly connecting spade connector to battery positive. MAKE SURE YOU ARE IN NEUTRAL. I bet it would consistently crank.

 

Well, my '94 (auto) has one.

But if lyf001 has looked, perhaps Toyota was not yet using the relay in 1990.

 

WOW! First time I've learned of that gen with starter relay on the A/T. Is it in engine compartment (good), or on kick panel (bad) like JPL?
Those years really a bunch of electrical variations between years.

 

Until lyf001 looks under the hood (instead of JB 1, which is in the kick panel), we still don't know about '90.

 

@lfy001, Pls check locations below for starter relay.

AHA! Found these couple of schematics of A/T's with starter relays. However, solenoid power still has to pass thru NSS, instead of directly from relay to solenoid, so slightly longer wire run than on manual trans. Therefore, I guess the starter relay on auto trans appeared in 1990.




1990-1995 4Runner FSM shows starter relay in engine compartment. below...



However, JPL's 1991 22RE 4Runner has starter relay in kick panel ...

 

I looked under the hood in R/B 2 and there’s only 2 relays: Headlight and EFI for the 1990 V6 4WD version in California. I ohm out the ST1 contacts in the ignition switch and on the 6th turn, I saw around 80+ ohms, and around the 12th turn, I got 300+ ohms, but for the next 100 turns, I got a consistent 1 ohm. So either I wiped the contacts clean or else I possibly was getting the higher readings due to poor contacts between the meter leads and jumper cables to the socket terminals.
So I understand that you’re saying that the original factory design of this ignition setup would work okay when new, but due to the aging and wear of the ST1 and NSS contacts, that now they are working marginally, correct? So the fix is to add the hot shot mod to reduce the higher resistance in the factory wiring down to a much smaller resistance.

 

The modification Rad4Runner is suggesting, as I understand it, is to avoid passing the solenoid current (around 5 amps) through the ignition switch. Your measured 80 ohms might be low enough to close an external relay (hotshot or OEM starter relay), which would allow starting. But the variability of your readings suggests that your ignition switch is failing, and may eventually get to the point where it can't even operate a relay.

If you spend the ~$100 for a replacement switch, you should still consider the relay retrofit. It is certainly possible the high current damaged the original switch over the long run. And the long wire run for the high-er current solenoid didn't help.

 

Thank you scope103, I will look deeper into the relay mod.