Need electrical help ASAP!

[kelson]

Hey I would really appreciate some help with this. I have a 1jz swapped 1986.5. I was cruising on the Interstate today and I pulled off came to a stoplight and stopped. pulled off the line pretty hard and after I got into 4th I lost all power, the engine stalled. I knew what the problem was because a couple days ago my AM2 30A fuse blew and I had to go buy a new one (I don't know why that happened). So I pulled over and sure enough it was. Now I was desperate and in a hurry so just believe me when I say I needed my engine to start. So I um....bridged the fuse with a wire:cry:. worked for a couple of minutes and then I lost the engine again.

So Here is what I know:
power is still getting through the fuse because I have my fuel pump on a switch powered through the ignition wire that runs on that circuit.
I have fuel pressure because I can hear the pump working.
I don't think the injectors are firing for 2 reasons.
1. I cranked the engine a long time then smelled the exhaust and could not smell fuel (I've done this before and I uslually can)
2. I unplugged one of the fuel injector clips and tried to ground it with a wire, with the key in the on position, and no spark.
And lastly after I bridged the fuse I smelled something, maybe burning electronics, but I couldn't place it for sure.
I opened the ECU and it's all good.
oh ya almost forgot. the efi fuse is not blown I even replaced it to make sure.

I need to know:
What else I could have fried that would cut fuel.


I've been pouring over the wiring diagram and I'm not sure what it could be. My car is abandoned on the highway about an hour from where I live. HELP. here is a wring diagram and another with red tracing the circuit I am concerned about. And remember its a 1jz swap so its not exactly the same, I think just the ignition wring is different.

 

[kelson]

someone??

 

[nathaninwa]

Whats the wiring job like? ANything can be shorted, like the o2 sensor heater, or the fuel pump wiring.

 

[kelson]

Whats the wiring job like? ANything can be shorted, like the o2 sensor heater, or the fuel pump wiring.

wiring job is like 6/10 lol. but this is not a new swap. I haven't touched the wiring in 2+ years. It's a good angle though I will look into that when I go back to the car.

 

[nathaninwa]

Looks like the circuit you outlined, pretty much powers up all 12v stuff in the system. I wonder what happens if you put another fuse in, if it would blow right away.

 

[kelson]

Looks like the circuit you outlined, pretty much powers up all 12v stuff in the system. I wonder what happens if you put another fuse in, if it would blow right away.

well the last one lasted a couple of days + 2 hrs of driving today before it blew.

 

[Radial]

No spark and fuel means you are somehow missing the Crank&Cam signals to pulse fuel/light a spark.

But i Personally think your ECU is fucked...shorted capacitor for an example.

If you want to "sort out" for shortages, measure the power consumption (current draw, aka Amps) in that specific circuit.
Disconnect electronics, and start plugging them in one by one...always keep an eye on the current, once you see a huge increase of Amps, there is your fault.

But as mentioned, I think a capacitor is shorted in your ecu. Burned capacitors makes a very special "electronics burned" kinda smell.... wiring just smells like burning plastic.
Ans since you're missing spark and fuel, the only electronic thing controlling them is your ECU...so...yea.

 

[MightyAl]

I agree. Open the ecu case before you go tearing into anything else. The notorious 1jz cap might have bit you.

 

[stew_7mgte]

Not to be a complete ass but you knew you were blowing 30amp fuses so you jump it? You asked for this problem. Replace or have driftmotions repair your ecu. You could have damaged more, but start with the ecu.

 

[kelson]

No spark and fuel means you are somehow missing the Crank&Cam signals to pulse fuel/light a spark.

But i Personally think your ECU is fucked...shorted capacitor for an example.

If you want to "sort out" for shortages, measure the power consumption (current draw, aka Amps) in that specific circuit.
Disconnect electronics, and start plugging them in one by one...always keep an eye on the current, once you see a huge increase of Amps, there is your fault.

But as mentioned, I think a capacitor is shorted in your ecu. Burned capacitors makes a very special "electronics burned" kinda smell.... wiring just smells like burning plastic.
Ans since you're missing spark and fuel, the only electronic thing controlling them is your ECU...so...yea.

I'm only for sure missing fuel and I'm pretty sure that is because the injectors are not getting power they may still have signal. I know nothing yet about if I have spark. It could be there or it could not. I already opened the ECU and checked it thoroughly and it is fine. I couldn't see anything burned and there was definitely not a smell, I'm sure of that.

Not to be a complete ass but you knew you were blowing 30amp fuses so you jump it? You asked for this problem. Replace or have driftmotions repair your ecu. You could have damaged more, but start with the ecu.

Of course I did! I don't regret it, I was trying to make it to work for a very important meeting. Anyways I was actually able to borrow a friends trailer and tow it back last night so this situation is not as high of a priority. Still keep the ideas coming. Thanks to everybody who has answered so far.

 

[stew_7mgte]

Use a dmm and check for signal to the injectors. The ecu provides the ground path which fires the injector. If you have power to the injectors but still not firing then check the igniter. The efi fuse protected your fuel pump and maybe your ecu. But the igniter is on a parallel circuit. It should have popped the efi fuse as well.

 

[kelson]

Use a dmm and check for signal to the injectors. The ecu provides the ground path which fires the injector. If you have power to the injectors but still not firing then check the igniter. The efi fuse protected your fuel pump and maybe your ecu. But the igniter is on a parallel circuit. It should have popped the efi fuse as well.

hmm... Thanks. I think you're onto something. If my igniter is pulling from the same power as the 7m (and I think it is but I'm not 100% sure) it could be what is drawing the power. Thanks for the help. When it broke I did feel the igniter to see if it was hot and it didn't feel hot to me but I'll definitelly check this.

 

[destrux]

An amp probe is your best friend here. All you need to do is check the amp draw on the problem circuit starting from the fuse box and working your way along the circuit till you find what is drawing more amperage than it should. Then look for wiring shorts in that branch of the circuit and check the resistance of the component (compare to TSRM specs) to see if the component is bad.

The problem is an amp probe isn't really cheap if you don't already have one, but maybe harbor freight has a cheap version I've never checked. I'm fortunate enough to have one at work that I can use.

Good luck, wiring problems suck.

 

[kelson]

Found the problem! at least I think. The car isn't back together quite yet. The Am2 fusible link powers a white-red wire which goes to the key ignition switch and changes to a black-orange wire. The black-orange wire runs to B1-12 connection which powers half of everything in the engine bay. One of the 12v constant wires for an injector got pinched and grounded. When that grounded it meant no power to the fuel injectors, igniter, ignition coils, and a couple other things. So now I'm fixing that and it should be up and running. Merry Christmas everybody and thanks for the help.