rewiring engine control relay (to mitigate voltage drop in fuel pump when indicators flash)

[cael]

Hey 4GTuner members! Its been a while since I last logged in here, haven't been interested in doing any DIY work on the proton for a while .. glad my account still works :-D

I am seeking advice in rewiring the engine control relay so it is powered directly off the battery, as currently it seems to be on a common circuit with the indicators and reverse lights, in that a very audible voltage drop occurs when the indicators flash or when I put it in reverse - very audible because I am running a Walbro, so she purrs very loudly when running.

I have located the relay behind the ash tray (thanks Rob!) but I don't just want to chop in a direct run from the battery without fully understanding the implications.

my intention is to run a pair of wires directly from the battery terminals to the relay (fused of course) so that the relay is on its own circuit.

I understand though that this relay is not just for the fuel pump and so I want to be cautious.

The relay is a 4 pin as per attached photos I took, it has the two "COIL" pins, one "COM" pin and one "NO" pin.

The NO pin has two wires, one larger wire (red) and a smaller wire (black w/red)
The COM pin has two wires, both the same gauge and colour (black w/yellow)
The COIL pin which is next to COM is one wire (black w/yellow)
The COIL pin which is next to NO is one wire (black w/blue)

There is continuity between the COM and COIL pins (both black w/yellow) and they are both constant 12v.
The COIL pin next to the NO pin (black w/blue) is a switched ground, if the key is On then I get continuity with the chassis and can read 12v against the constants.
The NO pin appears to be a ground as I read 12.5v when testing against either black/yellow constants, however there is no continuity when testing against my chassis grounding points.

The question is simple I think, what do I wire around to get this on its own circuit, powered directly from the battery?
Would I run a positive from the battery directly to the COM and COIL? (and just chop, splice together and tape up the car's existing black w/yellow wires?)
If the issue persists, I might need to re-check my grounds I suppose.

Hope someone can ease my brain, I know what I need to do but I have over complicated it in my mind and I need a second opinion! Have I missed something?
Any assistance will be appreciated!

 

[unhuman]

If you are getting a voltage drop at the fuel pump with the indicators it is because the fuel pump wiring is too small to handle the load.

Common problem in Mitsi, I assume the same as Proton.

Need to upgrade the wiring as per here: http://www.vfaq.com/mods/pump-relay.html

I have done this, no more "fire engine" sound with the indicators. I am also running a "whinebro."

Don't need to touch the control relay.

 

[khubner1]

i'm preety sure your solid red will be your +12v source and the black with yellows are ign cicuits

the black with blue as per evo 1-3 is ecu main relay trigger (this is the wire that triggers the relay)

the NO pin is the one that runs down through the fuel pump to earth
NO stands for NORMALLY OPEN

so for me i'd be running a ned wire +12v to where the red wire is.

but tbh the beter more stable option is to run a 30 - 40 amp capable +12v source to the fuel tank and then put a new relay near the pump taking the +12v feed which is on the NO as the trigger wire and then to earth so wire it this way

pins on store bought relays are 87 85 30 and 86
85 on existing fuel pump +12v from the relay your looking at now
86 earth
30 from new power feed
87 to fuel pump

pins 30 and 87 can be reversed

 

[bazeng]

Agree. Relay in the boot with a direct feed from the battery. The original fuel pump 12v wire from the original relay will be the trigger.

 

[Ian91]

Yep, I also did all of the above when put in my aem pump, car wouldn't even run before doing this upgrade. 10/10 would recommend

 

[Ross Cox]

I concur. My battery is in the back seat area (rally VR4) I have a fused heavy wire from battery to a relay and on the my Walbro pump. The signal wire is the one that used to run to the pump. Cheers
Ross

 

[Rockabilly]

Wouldn't a DC to DC converter adjusted to 12.5V as it's output solve power drops?
I used to use one on a car HD audio player to maintain 12.5V
Even if the input power gets down to 9V, it maintains a constant 12.5V out
eg: If the player was left on, during cranking with varying voltage, the
DC to DC converter has a solid 12.5V output to startup the unit's circuit board!
I also use an AC to DC convertor set to 13.5V for this same car HD audio player
at home with a 12V transformer. So AC power spikes up/down aren't a prob.
A "constant" input voltage to the fuel pump. Old school protection, but gooda!
Aldo

 

[EVO-00X]

Have a read through my rides thread. I've spoken about upgrading and setting up thicker power cables when relocating the battery to the boot and using a 30A fused relay and the factory blue/black fuel pump wire as the trigger. ALSO, dont forget to run several earth wires from the battery in your boot to a few locations, not just one. I originally had my earth go to a rear strut tower bolt but it wasnt good enough. I added about 2 or 3 more to the boot floor and rear seatbelt bolt from memory and it made all the difference. I then coninued to fit an earthing kit in my engine bay with about 4 or 5 wires to ensure the body and engine bay were getting good earths throughout.

 

[BYBY5L]

Thats how I did mine too, was a quick little job but for these cars is a must,

The earth thing is another must imo, my gsr wouldnt start properly after I relocated the batt, had 2 average size earths from it and the standard engine earth straps. Made a grounding harness for the engine and ran a couple more off the batt and bam, was fixed

 

[khubner1]

Wouldn't a DC to DC converter adjusted to 12.5V as it's output solve power drops?
I used to use one on a car HD audio player to maintain 12.5V
Even if the input power gets down to 9V, it maintains a constant 12.5V out
eg: If the player was left on, during cranking with varying voltage, the
DC to DC converter has a solid 12.5V output to startup the unit's circuit board!
I also use an AC to DC convertor set to 13.5V for this same car HD audio player
at home with a 12V transformer. So AC power spikes up/down aren't a prob.
A "constant" input voltage to the fuel pump. Old school protection, but gooda!
Aldo

an operating cars isn't actually a 12.5v system it's actually closer to 15. 14. something is considered a healthy reading at the battery for a running car

 

[jake]

Im about to do the same thing, however for 2 044 external pumps and one intake lift pump. My plan is to construct a relay box in the boot near the battery box since my cars being rewired anyways.