I am trying to bring an 85 4Runner back to life. It had been sitting a couple of years. The PO told me it ran when parked ( - of course it did).
I pulled the tank, cleaned it and resealed it
Installed a new fuel pump
Installed a new fuel filter
I tried to start it after this and it would crank, but no start - it would "catch' for a brief moment
I pulled the cold start injector from the housing, left it connected to the fuel hose and jumpered the fuel pump
I had my uncle crank the motor while I watched and no spray from the injector
I looked at the FSM and did the ohm test on the Thermo Switch that sends signal to the CSI to fire - it tested at 30 ohms, within spec for the coolant temp
I did an ohm test on the injector itself and it tested way out of spec - it should be between 2-4 ohms and it tested at 11.6 ohms
I connected a 9 volt battery to the CSI terminals and it sprayed like a frightened skunk - good pattern
This is where I am in troubleshooting
SO, the CSI will spray with direct power, but still out of range for ohms
The thermo switch (timing switch) is likely ok?
It still could be a wiring issue, though the terminals all look to be firmly in the connector still
I am pretty sure the thermo switch just sends a ground through the signal wire to the ECU, which fires the CSI
Can I test the wiring by sending a ground through the wiring terminal to the thermo switch? I don't want to risk frying my ECU

Anything else you guys can think of? I could just by a new CSI and thermo switch, but they are not easy to find and are kinda pricey

 

Are you ankle deep in snow? Then your cold start isn't likely the root issue, but we'll come back to that.

There are a few more tests and some maintenance you can do. When the key is in the start position the CSI should have one wire with battery voltage on it. It's ground is provided by the timer and/or ECU. The cold start time switch grounds by its threads into the manifold, you'll probably want to clean this connection up as it's likely never been done and aluminum oxide is a poor conductor.

OK back to bit from above, the CSI isn't required to get the engine fired up. It was under 40°F this morning and my CSI is not plugged in.

You need compression, ignition and fuel. You can gauge compression by ear with some practical experience, at least enough to identify a dead cylinder, but you can't beat a compression test gauge. You can test for ignition with a spark guage, by holding you incandescent test light near the primary wire to the distributor while cranking, but this doesn't tell you if it's happening when it should where your timing light will verify consistent spark happens around the right time. Now it just needs fuel, skip straight to trying starting fluid if you can get it to run by spraying starting fluid past the throttle plate you've verified it's not one of the other two things it could have been.

Now you've verified the engine is mechanically sound (crank to cam timing isn't off due to a skipped chain) and properly tuned (ignition timing set in a reasonable range) and can work thru why there isn't fuel coming out of the injectors. You need an LED based test lamp to check for injector signals or one of the injector test lights you can plug into the injector harness. With your test light clipped to power you should see a dim LED when probing #10/#20 signal (injector ground) on the ecu or one side of the number one injector plug while cranking the engine.

You should track down a service manual also.

 

Thanks, and I will check it out. I had to chuckle at your first question, it was 107 here two days ago.