Trying to do 12v mod with no luck...

[Oppie1]

When I turn the key to acc, I do not get any power to the old relay wires that are spliced together (see pic for ref).

Am I correct in that there should be power running to these when key is turned to acc? I also tried it in the start possition with no luck. I'm going to try and replace all the relays, but not sure where to start or how to troubleshoot. I'm ok with wiring, but not something that I'm strong in. I do have some weird alarm system that the previous owner installed and I have no idea what's going on with that, but it seems to be disabled.

Does anyone know how I could test one of the stock relays with a multimeter?

Thanks!

 

[hvyman]

Do you have the fuel pump resistor hooked up? Its on the pass side shock tower.

When i did my swap i just removed it. As long as the yellow wire isnt hooked up you dont need it and it will be 12v.

 

[Oppie1]

Do you have the fuel pump resistor hooked up? Its on the pass side shock tower.

When i did my swap i just removed it. As long as the yellow wire isnt hooked up you dont need it and it will be 12v.

Resistor is long gone and is like the pic above. Stupid question, but does the ECU need to be connected for the relays to fire? I think I already tried hooking up the ECU with no luck.

 

[digihonk82]

im sure the pump doesnt energize until starter is turning

---------- Post added at 12:02 PM ---------- Previous post was at 12:01 PM ----------

you could try jumpering the fuel pump with key on and see if your mod worked

 

[Oppie1]

Resistor is long gone and is like the pic above. Stupid question, but does the ECU need to be connected for the relays to fire? I think I already tried hooking up the ECU with no luck.

Maybe answered my own question regarding ECU. I'll hook up the ECU again and try it, but I'm sure I tried it yesterday with no luck...

 

[Oppie1]

im sure the pump doesnt energize until starter is turning

Really? I always thought that fuel pumps prime/turn on when key is in acc position? I'll give it a shot tonight when I get home from work. Thanks for the help!

 

[digihonk82]

yeah IDK but its cool...if you jumper B+ and Fp in the diag box, you can get the system to pressurize when the key is in on position. Ive got the DM FPR and that's the best way to a)see if you have leaks in fuel system and b)adjust fuel pressure

 

[hvyman]

If the fuel pump resistor is gone your already getting constant 12 v to the pump.

And most jz swaps the fuel runs with the key in the on position.

 

[Oppie1]

yeah IDK but its cool...if you jumper B+ and Fp in the diag box, you can get the system to pressurize when the key is in on position. Ive got the DM FPR and that's the best way to a)see if you have leaks in fuel system and b)adjust fuel pressure

Good tip! Thank you!

If the fuel pump resistor is gone your already getting constant 12 v to the pump.

And most jz swaps the fuel runs with the key in the on position.

Yea, multimeter shows those wires as being dead. A buddy of mine will be stopping by to help me troubleshoot. He will be able to figure it out a little better than I...

Thanks,
Ryan

 

[Oppie1]

Checked all grounds, replaced all relays, efi fuses and relays are getting power. Its something with the passenger side kick panel where the two 12v relays are. One is a circuit opening relay and the other is a 12v relays of some sort. There is power going to those as well. Jumping B+ and FP with ECU installed does provide 12v to the fuel pump... Worst case is I find a wire not being used that is a switched 12v and use that for my 12v relay in the trunk... I do not want to do that though.

 

[Oppie1]

Looking at these two diagrams, I have a couple more things to test.