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86-95 Trucks & 4Runners 2nd/3rd gen pickups, and 1st/2nd gen 4Runners with IFS

NO power to b+ in diagnostic box

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Old Mar 1, 2012 | 06:36 AM
  #1  
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NO power to b+ in diagnostic box

I have no power to b+ in diagnostic box? Also is the efi relay and main relay the same? Thanks
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Old Mar 1, 2012 | 06:41 AM
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From: Queen Creek, AZ
I had the same problem, turned out my efi relay was bad which was not allowing the connection between BATT and B+. It was still clicking, but not making the switch.
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Old Mar 1, 2012 | 07:12 AM
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AWesome thanks can u tell me where the efi relay is located and what it looks like
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Old Mar 1, 2012 | 07:19 AM
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From: Queen Creek, AZ
It is in the fuse box in the engine bay, it is the relay that looks like a metal capsule. It switches constant power to ignition when you key on. Mine was still clicking even though it wasnt working. To check it, I pulled it out and ran a jumper wire straight from the BATT wire to B+, and it started right up. I cant recall the color of the wires though, however, the relay has a diagram on it, and you would put the jumper in between the two wires where the switch is. The other two are for ABS and ground.
EDIT: I believe the B+ is the W/R wire, but I cant remember what BATT is.
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Old Mar 1, 2012 | 07:24 AM
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From: Queen Creek, AZ
First of all, does the vehicle start? If the relay is bad it wouldnt even start since the W/R wire goes to the COR and powers your ECU.
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Old Mar 1, 2012 | 07:27 AM
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http://www.ncttora.com/fsm/1990-1995...c/relayloc.pdf page 22
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Old Mar 1, 2012 | 08:09 AM
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THe truck will only start and run when I jump fp in diagnostic box directly to positive terminal on battery
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Old Mar 1, 2012 | 08:16 AM
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ALso truck is 1987
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Old Mar 1, 2012 | 08:18 AM
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From: Queen Creek, AZ
So your fuel pump isnt being powered on? Check the VAFM, if you push the flapper in with the key on you should be able to hear the pump come on. If not, check the COR. And like I said before, the W/R wire from your EFI relay goes to the COR, so if you dont have power there, you dont have anything going to the COR to tell the fuel pump to kick on.
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