Fuel Pump Relay Wiring
 

So, I know this should be a very simple task but I just can not figure it out for some reason. Ive looked up and tried so many different ways to wire up a relay in this configuration ive totally lost track so im hoping for just a clear cut answer..

Its an E420D and im using aux 7 for the fuel pump and can never get the fuel pump to turn on when inverting the signal. I do know that the ecu is providing the ground to the relay.

Is this something silly like the wrong type of relay or something? and ive been using 87 NOT the 87A, is that correct?

These are the instructions that came with my relays.

Hi Steve,

Yeah 87 should be the correct one, and the wiring will look like this (attached). You can verify with a multimeter if the relay works as it should. But can I ask why are you using this one and not the factory fuel pump relay?

Thanks.

I'm doing it this way because it's what's people where suggesting I do https://www.rx7club.com/showthread.p...671&styleid=20 Can both of the 12v's share a wire or is one constant and the other ignition switched? Thank you for your reply Mark!

The above is correct. 86 should be switched 12v. 87 should be fused.

Thank you guys. I thought the ecu was providing the ground, got me all confused. I'll give it a try asap!

ECU does close to ground.

So the red M goes to the fuel pump? Isn't that the international symbol for ground?

M is the pump motor.

The - side of the pump does go to ground. The relay feeds the + side.

Gotcha, thank you. I'll let you know how it goes.

Wired it up that way, inverting the signal and still nothing. giving the pump direct power does make it turn on, so i know my pump is still good.

Why inverted?

Inverting it on the adaptronic should turn the fuel pump on, as a way of testing it.

Yup "inverting" should toggle the ECU aux output on/off.

Have you checked the relay, if pin 30 and 87 gets connected when the relay is ON? If you have a multimeter, you can check if pin 30 gets 12v when the relay is ON (which is the voltage coming from pin 87).

Thanks.

well i was playing with my car and when i switch the ignition from on to accessory, the fuel pump will run for about five seconds and the relay in my sakebombgarage aem coils' wiring harness starts buzzing. gonna go back over ALL the wiring. any suggestions?

I also realized that's the only time the adaptronic lights up as well (been plugged in usb and I assumed everything was still working as it should) I checked how I wired up the adaptronic, the constant 12v and ign switched 12v is correct but all my ign switched power isn't working correctly with the key for some reason. No wonder nothing works.

Hmm that's weird. Are you saying the ECU only powers up when the key is switched to ACC?
Can I ask where Adaptonic pins 1A and 1B are wired?

Do you need a wiring diagram by the way? email me if you need one - mark@adaptronic.com.au

Thanks.

Correct, only on acc and only when coming backwards with the key, not forward. I haven't had a chance to work on it since discovering that . I used the factory ecu's power and ign power. I forgot that before I crashed my last shell (with this steering column and ign) my stereo would stay on occasionally after turning the car off. The stereo was wired correctly too I swear, gotta be an ign module problem? I have the diagrams but thank you.

FC? Are you sure the circuit you've used for switched 12v is actually 12v and not 8? Check it.

So idiot of the year, I had a chance to look over all the basics (fuses, my wiring, grounds etc) ecu ground on the block was loosened last time I was working on stuff making the everything wayyyy harder than necessary. I am still having an issue with my ignition like suspected, when I turn everything off and take the key out everything 12v ign stays on occasionally and i have to switch the key between off and acc to get it turn off, i might end up posting about that in the fc section as its not adaptronic specific. The ecu is powering up when its supposed to now at least.

I tested 1A and it has a constant 12v, 1B has 2v with everything off and 12v when the ign is on. Is 1B getting 2v a problem?

The relay for the fuel pump is wired up as you guys said to and testing with my multimeter, with the positive probe on the + battery post and the negative probe on 85 of the relay it gets 12v when the adaptronic is inverted but still no fuel pump. And the fuel pump still works when i give it direct power.


Thank you again for your replies and help guys!!

Hi Steve, 2V on 1B wouldn't hurt the ECU, but yeah that still needs to be sorted. Are you able to measure 12v at relay pin 30, when the aux output is enabled?

Got it working! Grabbed a different switched 12v for the relay and it's working great! So thankful for all the help! I've been stuck on this and about to give up for a couple months now. Thank you again very much!

Since ive got you guys here... will the wiring for my water meth pump on a pwm output be wired the same as the fuel pump as far as the relay goes?

Yey high five Steve! :)

Do you have a wiring diagram or recommendation from the pump manufacturer on how to control it using a PWM signal? I've seen some pumps with an extra pin for the PWM control input for example.

Thanks.

I bought all my water meth components from turbosource and they didn't come with any info, it's all aem tho.