Fuel Pump Voltage

[YYCSupra]

Hi there, I'm trying to trouble shoot something and could use some assistance. I have a jza70 1jz engine in a mk3 supra and when I put a voltmeter between Fp and B+ on the check connector I'm getting a bit over 4 volts at idle. I have not done a fuel pump relay mod. Can someone check their 1J to see if they are also getting that same reading please.

Thanks!


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[hvyman]

That's too low even for a 7m. Usually the resistor gets bipassed when doing a swap aswell

 

[YYCSupra]

Yeah should be either 8v or 12v I think. My afrs are all over the place. At idle I'm at 18. I am wondering if my fuel pump is on its way out.


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[hvyman]

If your voltage is low then that is your problem. You need to trace it back from the relay to main fuse box and see where your issue is. Possibly wired wrong from the swap

 

[YYCSupra]

Weird thing is it was running just fine last week. Swap was done about 10 years ago. I did recently go single turbo but it was running well afterwards.


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[YYCSupra]

Think I found my problem, it is between EFI relay and ECU Bat. Showing I have a short there or loose connection.


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[YYCSupra]

Apparently that was not my problem. Got some serious electrical issues going on. Car won't even run unless I jump FP and B+ on check connector. And even then it runs a bit rich on that setting. I checked for continuity between almost all connections in the efi circuit but nothing seems out of whack. Didn't check voltage though. All grounds to ecu seem fine. Bypassed fuel resistor and relay and no dice. Used TSRM to check relays and they seemed fine. Hope it makes it to the shop!


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[YYCSupra]

Another odd thing that is happening is when the throttle is quickly flicked my headlights come on!?! If I remove my headlight relay it doesn't do it anymore.


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[hvyman]

You have a power or ground issue. Something is loose or missing or about to break

 

[YYCSupra]

Yeah, you are absolutely right. Had it in the shop and the EFI issue was a loose power pin on my ECU (green wire) will find out tomorrow if it also solved my headlight issue.


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[YYCSupra]

My headlight problem was a weird one too. Whoever did the swap tied in a pwr wire to the ECU. This pwr wire existed for the 7M but wasn't needed for the 1J. Disconnected the wire and no more headlight issues!


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