EFI relay / fuse

[brillo_76]

There can be a ground short in an injector? Didn't know that was possible. So a bad injector can cause this? So the plenum intake has to come off. To check those wires or put in new injectors. I didn't know an injector could short out. Anyone else have any ideas? Is this because it only blows during start up that you think it could be a bad injector? Thanks so much.

The injectors are solenoids. Everything can short. All a short is a direct path to ground with lower or zero resistance. You are going to have to verify all your wires are good with their insulation intact.

This could be one if your injector wires has the insulation warn off and hitting the block which is ground. You will notice each injector has 2 wires correct? Being the injectors are o ring to the fuel rail and they are O ring to the intake ports. So I would find your EFI electrical wiring diagram and start verifying everything to rule things out. Until you find what is blowing your EFI fuse. Good luck.

 

[Batmmannn]

Yes I figured that but I don't have the diagram and so far I can find nothing wrong melted or shredded. I'm going to have to pull the intake plenum which appears to be a huge PIA Does anyone have a diagram for the 93? I've disconnected most suspect on the circuit but without any relief. I've replaced a lot already. OCR, ECM, main relay, computer, fuel pump. Thanks. Anyone got any other possibilities?

 

[brillo_76]

Like I stated before. Your rig is a gen 2 1992. This is the gen 3 ( 1996 -2002) forum. You probably have better success on that forum. As we don't have 3.0l v6 ours as 3.4 liter...

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[Batmmannn]

Yep I'm trying in that section but no responses yet. Is there a way to get a notification in email or text for when someone responds? Thanks for your help.

 

[19963.4lsr5]

If it only happens with the key in the start position look at the circuitry at the start switch and what it operates, compared to the ECM holding the relay energized after starter engagement.


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[Batmmannn]

Thank you for your help. Any suggestion is greatly appreciated. I'm going to pull the intake hopefully today to get to those injectors and unhook them and inspect the wires. They make these cars too complicated. At $120 an hour for a shop, I'm not going to take it to them. A short is a wide open charge for them. I can't get a price nailed down from any shop to find the short in the system.

 

[Bad Luck]

Thank you for your help. Any suggestion is greatly appreciated. I'm going to pull the intake hopefully today to get to those injectors and unhook them and inspect the wires. They make these cars too complicated. At $120 an hour for a shop, I'm not going to take it to them. A short is a wide open charge for them. I can't get a price nailed down from any shop to find the short in the system.

Not surprising. Shorts/breaks in the wiring are difficult to find. Sometimes it's easiest/cheaper for everyone involved to run new wiring for the problem circuits rather than splitting open a harness and tracing wires. Sometimes you can get lucky and see it with a very high resolution infrared camera, but that only works on shorts on constant power circuits.

 

[Batmmannn]

Well, I wouldn't have believed it but unhooking the fuel pump I just installed stopped the short. Brand New Bosch fuel pump. Perhaps the polarity is backwards? Perhaps the carrier went bad? Perhaps the pump is defective? I'm going to swap the wires and see what happens. The carrier was very Rusty and I cleaned it up. I read where red wire doesn't necessarily mean positive wire on these Bosch pumps. I'm a bit miffed. I've been weeks trying to diagnose this off and on. The pump ran OK in the key on position and the fuse didn't blow. Or is it still a bad injector and the fuse didn't blow because the pump wasn't pushing gas to ground the injector?
Thoughts anyone?

 

[Batmmannn]

SOLVED!!!
well it seems working under the vehicle without much light I had reversed the new connector on the fuel pump. I swapped the wires back, hooked everything back up that I had taken apart for testing and she started right up and kept running. I'm such a dumbass. Anyway thanks to all that responded. First start in 16 years. Polarity matters it seems on a Bosch. Many claim it doesn't matter but for this vehicle it does. Strange that the pump worked fine in the key on but only blew the EFI fuse during start attempts.

It seems I am my own worst enemy and I'm not a newbie. I've replaced many fuel pumps in the past.

I got a running 4Runner Guys!

 

[brillo_76]

SOLVED!!!
well it seems working under the vehicle without much light I had reversed the new connector on the fuel pump. I swapped the wires back, hooked everything back up that I had taken apart for testing and she started right up and kept running. I'm such a dumbass. Anyway thanks to all that responded. First start in 16 years. Polarity matters it seems on a Bosch. Many claim it doesn't matter but for this vehicle it does. Strange that the pump worked fine in the key on but only blew the EFI fuse during start attempts.

It seems I am my own worst enemy and I'm not a newbie. I've replaced many fuel pumps in the past.

I got a running 4Runner Guys!

Good you got it fixed. Polarity always matters.


For the future, it's best to always use denso or toyota fuel pumps aa the aftermarket pumps mostly don't last very long...

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[19963.4lsr5]

SOLVED!!!
well it seems working under the vehicle without much light I had reversed the new connector on the fuel pump. I swapped the wires back, hooked everything back up that I had taken apart for testing and she started right up and kept running. I'm such a dumbass. Anyway thanks to all that responded. First start in 16 years. Polarity matters it seems on a Bosch. Many claim it doesn't matter but for this vehicle it does. Strange that the pump worked fine in the key on but only blew the EFI fuse during start attempts.

It seems I am my own worst enemy and I'm not a newbie. I've replaced many fuel pumps in the past.

I got a running 4Runner Guys!

The engine starts now and runs good?


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[Bad Luck]

SOLVED!!!
well it seems working under the vehicle without much light I had reversed the new connector on the fuel pump. I swapped the wires back, hooked everything back up that I had taken apart for testing and she started right up and kept running. I'm such a dumbass. Anyway thanks to all that responded. First start in 16 years. Polarity matters it seems on a Bosch. Many claim it doesn't matter but for this vehicle it does. Strange that the pump worked fine in the key on but only blew the EFI fuse during start attempts.

It seems I am my own worst enemy and I'm not a newbie. I've replaced many fuel pumps in the past.

I got a running 4Runner Guys!

For future reference 3rd gens don’t run the fuel pump until you start the engine and the ecm sees that the engine is turning over.