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!black
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4,625 Posts
Discussion Starter #1
This is driving me nuts. I can just feel that it's going to be a ground problem somewhere...

My problem is that the ECU (and all the sensors) are not getting power when the ignition switch is in the on position.

I have checked power at the main fuse box, and 12v is flowing though the EFI #1 fuse. Power is also flowing to the ignition pin, the car will crank (which means power is getting sent from the ECU to the starter relay). However, there is no power being sent to the EFI main relay via the grey trigger wire. I can't get a reading at the ECU for the wire (Pin 24 on the smaller connector) but I'm not 100% sure the paperclip is making down into the wire all the way. I get no voltage at the relay junction itself in the fuse box.

I've checked all the grounds, I was originally missing one in the harness. Everything is tight, battery have full charge.

What's odd is my old ECU (NA, but the power wiring scheme is the same for both) is also showing no voltage when it's installed. Since it worked fine when it was pulled, I highly doubt I have 2 bad computers sitting here. Another odd thing is that if the key is in the on possition for a while, the low-oil light will illuminate (because the connector has a pin missing that I haven't fixed yet). Odd, how can the sensor be read if there is no power to the system?

It's something either in the harness or a ground. I just don't know what :(

Any ideas?
 

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1,638 Posts
Did you check the wire going to the fuse block in the engine bay? It connects underneath it and you might have a bad/broken connection.

Goodluck!
 

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!black
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4,625 Posts
Discussion Starter #3 (Edited)
I read 12v on the one side of the relay (battery, constant hot), but no voltage to the other side (pin 1) when the key is in the on position. Grounds are good, so the relay should pick upI checked the relay from the bottom (took appart the fuse box) and same result. I cant seem to get a wire fed down into the harness while it's attached to the ECU to check voltage leaving the computer on the grey wire.

I can jumper the battery side to the B+ side of the relay, and the fuel pump will kick on while cranking. But the CEL doesn't illuminate when they key is on, so I'm stumped.
 
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