Ignition not cranking the engine (only click is heard at starter)

[Zed Head]

I've probably added a lot of confusion here by looking at things that are indirectly associated with starting. 

If you want to check if power is making it through the ignition switch I would check for voltage at the black wire with yellow stripe (BY) at the seat belt relay when the key is turned to Start.  That is a straight shot, through just one connector, from the switch to the relay.  One of the two wires at the plug should have power at Start.  The relay just stops it from passing through to the starter solenoid.

The thing about the relays clicking is that when you turn the key to Start the Accessory relay opens to cut power to accessories during starting.  So the click you hear might not be directly related to your problem.

Actually, this diagram frm the FSM clears up a lot, I think.  The inhibitor switch controls the starter relay, the starter relay controls power to the solenoid.

After checking for power, if you have it, verify that the other BY goes to the solenoid.  Then just jump them together as CO suggested.  The engine should spin just like jumping it at the solenoid. 

Edited February 7 by Zed Head

[zKars]

Being lazy and not having read the entire thread, I have a suggestion that perhaps has not been tried yet. 

Replace the spade connector on the end of the BY wire at the starter. It may “look” just fine, you may have even cleaned and tightened the metal contact. I had one where there was only one strand of wire still crimped under the terminal tangs and that strand (like the rest) were filthy and corroded. No way to get enough current flowing to engage the starter solenoid. Snip, strip, scrape any corrostion off of the bare wire, crimp a new 1/4 FM terminal, stuff it on the starter terminal. 

[Captain Obvious]

14 hours ago, MH77280Z said:

Cleaned all 4 grounds (engine, intake, firewall and AFM) - same result - only click at passenger relay no power to starter

Cleaned all 4 contacts under the car at the inhibitor switch - same result - only click at passenger relay no power to starter

Took off starter relay and shorted two BY connectors - same result - only click at passenger relay no power to starter

What next? is this click at the passenger relay panel coming from ignition relay?

Yes, the click coming from the area near the passenger feet is probably the ignition relay. But it's a non-problem. The B/Y jumper across the starter relay takes all that out of the equation. in other words... With the starter relay bypassed (by shorting the B/Y wires), the ignition relay does not have any effect on the starting circuit. You should be able to completely remove the ignition relay from the car and it should still crank.

So what next?  I'd go upstream... Next time it acts up, I'd hotwire directly across the ignition switch and see if you can get the starter to engage. I know you said it's a new switch, but who knows. Jumper from White/Red to the Black/Yellow and the starter should spin. 

If it still won't crank under those conditions, I'd wiggle your fusible links around and try again.

Failing that, it's time for a meter and really start digging into things.

[MH77280Z]

43 minutes ago, Captain Obvious said:

Yes, the click coming from the area near the passenger feet is probably the ignition relay. But it's a non-problem. The B/Y jumper across the starter relay takes all that out of the equation. in other words... With the starter relay bypassed (by shorting the B/Y wires), the ignition relay does not have any effect on the starting circuit. You should be able to completely remove the ignition relay from the car and it should still crank.

So what next?  I'd go upstream... Next time it acts up, I'd hotwire directly across the ignition switch and see if you can get the starter to engage. I know you said it's a new switch, but who knows. Jumper from White/Red to the Black/Yellow and the starter should spin. 

If it still won't crank under those conditions, I'd wiggle your fusible links around and try again.

Failing that, it's time for a meter and really start digging into things.

Checking the ignition switch today and will get back ...

[MH77280Z]

11 hours ago, MH77280Z said:

Checking the ignition switch today and will get back ...

Guys i had installed this ignition switch brand new 6-8 months ago and seems like after installing a new one today from Oriellys the car starts like a dream. In the process cleaned all grounds and wires and a new starter. Planning to keep this new one in. I really appreciate everyone's input. This one could had been a nightmare but at the end turned out to be the ignition switch.

[Captain Obvious]

Awesome. I suspected the switch from the beginning, but was reluctant to send you there right away because of the recent replacement. Glad you got to the bottom of the issue, and hope you're good from this point forward.  

If you haven't already... Don't forget to remove the jumper around the starter relay and reconnect the relay. You don't want to accidentally start your car in "D"!  

[MH77280Z]

4 minutes ago, Captain Obvious said:

Awesome. I suspected the switch from the beginning, but was reluctant to send you there right away because of the recent replacement. Glad you got to the bottom of the issue, and hope you're good from this point forward.  

If you haven't already... Don't forget to remove the jumper around the starter relay and reconnect the relay. You don't want to accidentally start your car in "D"!  

For sure 🫡

[Zed Head]

15 hours ago, MH77280Z said:

i had installed this ignition switch brand new 6-8 months ago

Odd.  Where did you get the switch?  I wonder if it was a bad connection that got fixed while you did the work.  The extra stuff.  You can use your meter to check continuity through the switch from the power supply wire to the outlets.

Doesn't really matter, just curious.  I finally understand the inhibitor switch circuitry on these automatics now.  Never had a reason to dig in to it before.  Thanks for the puzzle.

[Captain Obvious]

I've never liked the way they run the starter solenoid current directly through the ignition switch. I think they should have put a relay between the switch and the solenoid. That solenoid draws like 8-10 Amps and really chews up the contacts in the switch.

Kinda stupid how on the automatic they DID put a relay in, but didn't actually use the relay to switch the starter solenoid current. They just used it as an interlock. They COULD have put the inhibitor switch on the contacts and the pull in coil on the ignition switch (instead of vice-versa). Operation would have been identical, but it would have switched the higher current load side with the relay.

[Captain Obvious]

Here's what happens to the inside of the ignition switch after it switches the starter solenoid a bunch of times:

And here's what you should do about it (note that this is for the manual trans. The auto already has a relay, but as mentioned above, they didn't wire it like this):

Edited February 9 by Captain Obvious