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Dj, ASE Certified Technician
Category: Toyota
Satisfied Customers: 1910
Experience:  ASE Master Tech, 30+ years in automotive repair.
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Toyota Pickup: My 1985 toyota pickup won't start. It is a 5

Customer Question

My 1985 toyota pickup won't start. It is a 5 speed 4x4 with 22re.
Submitted: 2 years ago.
Category: Toyota
Expert:  Dj replied 2 years ago.
Hello and thank you for requesting me.
There are two electrical parts to the TPS. The first part is a switch that turns on and off just as you come off of idle. What this does is send a signal to the ECU that you have your foot off the gas. So if you're coming down a long hill, let your foot off the gas, and the engine RPM is over about 1,800, the ECU turns off the injectors.
The second part is like a volume control on a radio. The more you press on the gas, the more the throttle is turned up. This signal goes to the ECU and the ECU responds by giving the engine more gas.
The most likely failure is the switch portion of the TPS. If the ECU thinks the throttle is closed, it will turn off the injectors and the engine won't run.
Does this sound like what might be happening with your truck?
Expert:  Dj replied 2 years ago.
Here is a good tutorial on how the TPS works and how to test it.
Please let me know what you find and we'll figure this out.
Customer: replied 2 years ago.
The first thing after it broke down and got it home was put a new oem tps on and calibrated it via the 4krawler website. And this did nothing. All fuses have been triple checked and all grounds cleaned even the igniter mounting bracket. All sanded to bare metal. I have no power to fuel pump no power at coil/ igniter. I did the fuel jumper test and even jumped the co relay and nothing. I put 12v direct to fuel pump and can hear it in the tank. I also have nothing to computer terminals sta and e1 and nothing from sta to body ground. I have power to the efi fuse with key on but dies off when in start position. I tested the ignition switch according to the fsm I bummed from the toyota dealership, it test good.
Customer: replied 2 years ago.
So I have no spark, no fuel, no heater fan and the clock shuts off when the fasten seat belt sign turns off, when key is switched to the on position.
Expert:  Dj replied 2 years ago.
Great information.
Power goes from the battery, through the fusible link, to AM1, AM2 and ALT.
From AM2 power goes to the EFI fuse. The problem is between the battery and the EFI fuse.
It could also be a ground, so just for a quick test, hook a jumper cable from the negative post on the battery to the engine.
Then let's check power through AM1, AM2, and ALT. It's got to be right in that area.
Customer: replied 2 years ago.
I have checked power at the fuses on both sides of am1, am2 and alt with key in all positions, with fuse box apart. There is batt power at all 3 no voltage drop. I get batt voltage at efi fuse utill I turn the key to on position. I tried the ground jumper wire to a couple different locations on engine including efi main ground on intake and nothing. I have a 6' jumper wire with alligator clips, even went inside the cab to fuse box ground to -batt. No change.
Expert:  Dj replied 2 years ago.
Lets try running a jumper wire from the positive battery post to the B+ terminal in the DIAGNOSIS box and lets see if the engine will run.
This will bypass the IGN fuse, EFI fuse, EFI main relay and the ignition switch. Also check to see what voltage you have on the red-black wire on the ignition coil.
Customer: replied 2 years ago.
Ok I will try that when I'm off work. My truck has the plug on the driver side with seperat fuel pump check plug. Witch wire should I put power to, I think there is 2 or 3 wires on the diagnostic plug.
Expert:  Dj replied 2 years ago.
What I think is happening is that in the past, either AM1 or AM2 failed and somebody wired in an aftermarket inline fuse. But it could also be there to run power to another accessory, like lights or a radio or a winch, something like that.
Please let me know what you find.
Customer: replied 2 years ago.
I was able to try the jumper to the diagnostic plug from +batt. Nothing changed. One of the wires was a ground, found out with multi meter. Before applying power blindly. I have owned the truck for 5 years and have done engine and tranny rebuild 1.5 years ago. I have never seen anything added or modded in the electrical system. I have been trying to figure this out for a couple weeks now. No power at coil at all.
Expert:  Dj replied 2 years ago.
I'm running out of ideas, so I'll put your question back into the expert pool. This will put your question back up so everybody (on this end) can look at it and give you an answer.
Please don't respond to this message or it will lock your question up. Wait for a response from one of the other experts.
Sorry I couldn't help you on this one.
Customer: replied 2 years ago.
No worries. Thank you. When the truck broke down it started back up after a min of sitting. To move to a safer place on the side if the road but it died again before I made it to a pull off but I was able to coast in. Then got out looked around and found nothing. So I tried the key again and it cranked but no fire. So I tried one more time with gas peddle smashed to floor and boom started. Then it shut off, so I unplugged the tps and it started right up like nothing was wrong. It did idle high. Drove home no prob. Parked it and that's were it stayed, it would not run