Toyota Repair Problems? Ask a Mechanic for Answers ASAP
Hello and thank you for trusting us with your question. I'm DJ.
I would like to activate the fuel pump and see if it works and if the engine runs.
Under the hood next to the fuse box is a small black box marked DIAGNOSIS.
Inside the lid it a chart that shows what each of the terminals is.
Jumper B+ to FP. I normally use a paper clip bent into a U shape. The terminals are shaped like this O_O and the paper clip will fit right into the O part.
This should turn on the fuel pump when you turn the key to the RUN position.
Let me know if you can hear the fuel pump and if the engine starts.
Leave the paper clip in place for the rest of the testing.
Is this a 4 cylinder or a 6 cylinder?
There a black and red wire that goes to the injectors. Can you check to see if you have power on that wire with the key in the RUN position?
I'm sorry I haven't been able to respond sooner. I've spent the last two days in hospital and I just got out this evening.
The injectors should get 12 volts.
The next thing to check is the voltage at the coil. It's the same wire that goes to the injectors, and should have 12 volts with the key on.
If it showz 7.5 volts, then check the AM2 fuse under the hood. There's got to be corrosion or something like that somewhere on the supply to the injectors.
Let me know what you find and we'll figure this out.
If the black and red wire was grounded, it would blow the fuse.
There is a common problem with the ground connection for the injectors. The ground is on the intake manifold, right in the middle where it's bolted to the head. This is the most important ground on the vehicle so it's good to check it.
When a wire is showing 7.5 volts it's because there's excessive resistance someplace in the circuit between the battery and the igniters. Unless the insulation gets worn through or cut, the wiring itself doesn't normally cause a problem. Most of the time the problem is at the ends of the wire right at the terminals, because this is what's exposed to the weather.
Power from the battery goes to AM2. From there it goes to the ignition switch. From the ignition switch to the injectors and coil.
So I would check the voltage on AM2 on both sides. Then take the cover off the steering column and check measure the power on the back of the ignition switch going in and out. Power into the switch is on the white-red wire. It goes out on the black-red wire.
What I would do next is run a jumper wire and get 12 volts to the coil and injectors. If the engine starts and runs, then we know we're on the right track.
If that works, there's a dark gray connector on the right side under the dash called IH1. It's got a lot about 17 wires in it. Just make sure it's got no corrosion. Sometimes if the windshield leaks it will drip right into this connector.
There's a splice in the wiring where the wire that comes from the ignition switch attaches to the wires that go to the coil and the injectors. It's wrapped up in the harness and it's right above the booster. You could cut the harness apart and check that, but honestly I would go to that much trouble.
I would just run a wire to bypass it. Go from the ignition switch to the coil. Leave the old wire in place. You would basically be piggy backing the wire. If this was a restoration project on a 1927 Pierce Arrow it would make sense to find the fault and fix it. By why spend 2-3 hours when it will only take 45 minutes to bypass it. Just tape the new wire to the existing harness, make sure it's not rubbing against anything.
Remember, spring break and Girls Gone Wild is only 5 weeks away. No time to waste.
Attach it right at where the black-red wire is attached.