I have a 1993 Toyota P/U with the 3.0 v6 that I got from my brother. It has 189k on the truck but my bro had a rebuilt engine put in about 30k miles ago. When I got the truck it idled rough and I could smell raw fuel and see it dripping on the ground. To make a really long story short I replaced and fixed a ton of stuff. I upgraded the alternator to a 120a unit, Installed flamethrower injectors, new fuel pressure damper and fuel press regulator, new injector seals, fuel filter, hot tanked the intake plenum and manifold, cleaned the throttle body and MAF, cheap cold air intake, new plugs, wires, cap/rotor, all new silicone hoses, new battery, new timing belt and tensioner, water pump, fan bracket, belts, etc..

I got everything back together tonight and I went to start the truck... nothing. When I turn the ignition I get the FAINTEST click from the starter relay. I switched it out with another one and same thing... very faint click. I checked my battery voltage: Static- 12.2v Load- 11v. I guess its a little low but I dont even hear the fuel pump priming when I turn the key to position before cranking. I checked that all electrical connectors are secure. I checked that the small wire is secure on the bottom of the starter. I added an additional ground from the negative battery terminal to the body. I also have a ground on the block above the A/C compressor.

I'm stumped. Any helpful advice would be greatly appreciated. TIA

 

Don't worry about the fuel pump right now. If the starter isn't being activated, you need to figure that out first. Get a cheap multimeter and an assistant and figure out if voltage is getting to the starter. First, check the battery voltage on the battery terminals, not the cable connectors, while someone has the key in the start position. It should drop but stay above 10V or so. Next move your probes to the cable connectors and do the same thing. Shouldn't be much different. If it is, you have a bad connection at the battery. Keep moving your probes toward the starter until you find a place where the voltage is getting lost.

 

12.2v sounds too low (you should get closer to 12.6v, temperature dependent. Yeah, 0.4v is all it takes to get to no-start). 11v with key to start sounds like the starter load is pulling the voltage down (as expected), but to a point where the starter does not have enough voltage to turn. So I would charge the battery first.

(RJR thinks 10v might do it, but your multimeter reading could be off by a volt, and even 11v is pushing it.)

The fuel pump does NOT run with the key at "position before cranking." It doesn't start until the key is to STArt. (and if your starter isn't turning, you should be able to hear he pump. I can hear mine in a quiet garage standing at the diag. connector.)

There are a handful of other useful tests to do with the multimeter, but I would start by charging the battery, and if that doesn't do it, "follow the volts" as RJR describes.

 

OK. I had my assistant (8yr old son) sit in the cab and turn the key when told. I measure the voltage at the battery terminals static and load both @ 12.4v. At the connections it was 12.36v both static and load. Then I pulled the clicking starter relay out of the fuse box and measure the top (if looking at it from passenger side fender) terminal. THAT was only 10.31v static and 10.19 with load. Any idea what could be causing that? I did upgrade the size of the wiring when I installed the bigger alternator but I swear I was careful to keep everything in the stock location.

 

Sounds like not enough power is not getting to your starter solenoid, so you do not load the battery.
AND there is high resistance from battery to that "top"

I'd like to help but I have a 22RE so I would not know what "top" is.
Please put us at your truck. See signature.

 

Here's a picture of my starter relay: https://www.yotatech.com/forums/f116...switch-287859/
(Note my comment about how YOU have to figure out which pin goes where.)

On mine, pin 5 (which you might describe as "top") goes to the key switch, so it should have 12.6v with key to STArt, but 0v otherwise.

As a quick acid-test, try using a piece of heavy-enough wire to connect pin 3 to 12v as I have.

Generally, finding 10v anywhere in a vehicle is a bad sign. You start with 12.6v, and all the switches are only that; off or on. If you really have 10.3v at the starter relay, something is causing a big voltage drop, and with very little current. In your case, my first guess would be the ignition switch. For that, you can disconnect it at the steering column, and explore it with your ohmmeter.

 

Thanks for the replies guys. I have the day off and I guess I get to spend it trying to locate this issue. Oh, and don't worry about the 80a alternator fuse LOL. I had this issue before I butchered it. I'll pick up another one at the wrecking yard.

Here are a couple pics:


With key turned to "start".

 

Cool.
But please show closer picture of relay socket and indicate what color wire goes to which pin. If u have pin numbers from your schematic, so.much better.
(I have a 22RE so different from mine).
BTW, I like the battery terminals. Interface between battery and termnals are bare, shiny metal, correct?

 

Pls check if this schematic and wire colors are same as yours.
Then, with relay removed, probe pin 5 as shown in picture.
https://photos.app.goo.gl/XfAkYjgzJsmFwABi6

Pin 5 shud always hav 12V even with IGN off.
Pin 1 shud only hav 12V whn in crank position.
Let us know what u find out

 

Just copy and paste url to picture. Not loading right frm my smartphone.

 

Thank you for the schmatic! OK. I verified that it is pin5 with the larger white wire going to it which is only reading 10.3v with the ignition ON and reads 0v with the ignition OFF. Pin1 and Pin3 read 0v no matter what. Pin2 reads 0v when ignition OFF and 12.6v when the ignition is turned to START.

 

Are you absolutely, positively sure that PIn 5 has power when IG is on and even when not in START position? According to schematic, Pin 5 is connected directly with no switches in between, to battery through fuse block.

Sounds like your starter relay is wired wrong, contrary to schematic, just like any other trucks with torsion bars AND IFS like these.

BUT, let's be thorough, unlike incompetent shops/techs/stealerships.
Sounds like wires are contrary to schematic.
Please help us help you and others in the future by doubel checking your wires and relay pins.
With relay off the vehicle, Which TWO RELAY pins have SOME resistance between them? Which pin and wire color in the socket do they go to? When you connect these 2 pins to 12V, relay should click.
The remaining pins will have continuity between each other. When relay is disconnected from 12V these two remaining ins should have no continuity.

 

I had a jumper with a momentary switch that I made for my chopper years back and used that to jump the starter. I connected on end to the +B and other side to Pin3. I hit the button and the motor cranked like butter!!

Soooo I guess my issue is in the ignition switch?

 

In a way you're bypassing the ST1 contacts of the ignition switch AND the starter relay contacts pins 5 to 3, just like Scope103's remote start does.
Yes you have some voltage drop across the ignition switch ST1 contacts, that's from years of stress from carrying the approx 12Amps needed to energize the starter solenoid, because of the wrong wiring of starter relay.
Options: You can either:
1) Stay with the "jumper method", OR
2) Connect Pin 5 directly to battery through a fuse wire. 30-amps and12AWG should work.

 

OK. It wasn't easy but I was able to flip the fuse box over just enough to trace the wires...
Pin5 = White (larger wire)
Pin1 = Black/Red stripe (skinny wire)
Pin2 = Black w/ red dots (skinny wire)
Pin3 = Black/White (larger wire)

According to the schematic Pin1 and Pin2 wires a switched. Im not sure how much that affects anything because this truck actually ran before I tore into the top end of the motor. I did not touch ANY of that wiring in the fuse block. All I did was disconnect the stock alternator wire from the 80a fuse because I ran bigger wire from the alternator straight to the battery.

 

I may have found the issue... I pulled the dash apart and started checking voltage at the ignition. All was measuring around 12.4 volts UNTIL I traced the white wire going into this white fuse block in the drivers side kick panel. I measured the voltage at the spade connector in which the harness plugs into that runs to the relay under the hood. BINGO! It only measured 10.29v. I guess I have to pull the cover off of it and look inside to see what is going on inside there. The female spade connector in the plug has some corrosion on it so maybe water got inside?

Pics:

 

The "male" side of that connector is the "Integration Relay." The White wire provides always-on power TO the integration relay, so if you measure voltage to ground on the connector (female) side, you should get battery voltage (not 10.3). The male side powers the turn signals and taillights; I'm not sure why you're getting a non-zero voltage there.

 

That is strange. The male side is definitely reading 10.3v and the plug (female side) is reading 0v. Somebody definitely messed with wiring under the dash because they tapped off a power source to add electric windows but like I said, the truck did start and run prior to the motor work and I didn't mess with any of this wiring which is now giving me fits. Im really scratching my head. I ordered a FSM wiring book for my truck so hopefully that will help. I just really need to get this truck running because I need it for work.

 

The click-only issue with wrong starter / starter solenoid is often intermittent. Some solenoid plungers may operate more smoothly than others depending on conditions and that could mask the problem. Pls keep us posted when yuo get your schematic and verified that the truck is wired correctly.

 

UPDATE:

Factory wiring manual wont be here until 12/10 but I'm impatient and tried to do a little more digging today. This is what I know... The fat black/red wire from the ignition goes comes out on the otherside of the plug below the dash as a fat white wire. That appears to be factory. The red circled plug has 12.52v all the time. That loom appears to go through the drivers side fender portion of firewall.


Below is the male connector that is reading 10.3v. I peeked inside the ivory plastic housing and it doesnt seem like anything could be wrong inside there.


This plug circled in green goes to the upper backside of that ivory junction box. THAT must be plugged in to provide a reading at the above male connector which is reading 10.3v.


Thats all I have for now. I'm sure that isn't earth shattering information but now I'm going to test the wires in the above pic and see where that leads me. I should have an update later today. Thanks for all the support guys!!