1978 Toyota pickup (located in OR).


Symptom: slow crank and no-start condition. B wire from alternator previously melted (was replaced). E wire from alternator previously melted (was replaced). Something isn't able to pass current properly.


Facts: new battery. New alternator. New starter. New voltage regulator. Fusible links at positive battery terminal confirmed good. Battery negative post making good ground to chassis. Starter ground is good. Fuses are all good. New distributor that is getting 12V.

1. She won’t start, but she cranks over very slowly. I’m thinking I have a bad starter relay but I can’t seem to locate it. Does the 1978 Hilux even have a starter relay?

1. I'm also thinking that this may be associated with a bad ground connection somewhere. Any recommendations on where I should look besides what I’ve outlined above? Yes - I do plan to do a voltage drop test, but just haven’t yet had a chance.

Thanks!

 

What about direct voltage to the starter? Bypass as much wiring as possible and work your way backwards.

 

I'd double check the wiring since you recently did all those new parts. I'd also double check the battery, twice in the last 5yrs I've bought brand new batteries that were bad. Starter relay is either going to click and engage starter, or it's not.

 

Does anyone know where the starter relay is located in the 1978 Toyota pickup Hilux?

 

I don’t see a relay for the 78

 

Here’s a higher quality link for the photo.

https://imgur.com/gallery/8FAm8bq

 

With all those melted wires you may have more that you haven’t found yet. Check all your grounds, especially those from the block to the chassis. Check the alternator wiring harness for any signs of melting etc. New batteries can be bad. Check your starter solenoid wire connections. Won’t hurt to run a separate ground wire from the starter motor to a good chassis ground.

 

Thanks for the tips, everyone. I particularly appreciate the electrical diagram, Ivey.

I will perform my voltage drop test, starting with some easy grounding-bypass concepts, and let you know what I learn.

 

Well - thanks to you all, I easily determined that my slow crank and no start issue was a poor ground from the negative terminal of my battery. My simple fix involved moving my ground wire from the chassis position (a bolt right by my passenger side motor mount location) over to the engine block. She starts and charges beautifully now.

After doing some reading about proper grounding, I see that you’re supposed to ground block to chassis and negative terminal to block and/or chassis. Presumably this is a type of “belt and suspenders” approach. My 20R came to me only with a ground wire leading from negative terminal of battery to a bolt mounted directly adjacent to the motor mount. Am I missing a ground wire? Can all you 20R people help me understand how your vehicles are grounded (how many wires, where exactly are they located)?

Thanks!

 

You should have a ground wire running from the block(drivers side) to the firewall. My ground wire is secured to one of the bolts that hold the front parking brake assembly to the firewall.
You can never have too many grounds.
Add them wherever you have room. A separate ground from the starter motor to the chassis is always a good idea. This is my ground setup. Heavy black wire is from battery ground post.

 

Thank you, Fred. I will add a few more ground wires to ensure this doesn’t happen again.