Biggiesacks

Does anyone know what the current rating for the Stock ecu analogue outputs are? The reason I want to know is, I would like to have the ECU trigger 2 relays where its only triggering one now, but I don't want to burn up the ECU in the process.

Thanks

TheBoz

iTrader: (9)

I would guess no more than 4 amps.

Biggiesacks

4 amps would be way more then enough. I think most relays are under 500mA

TheBoz

iTrader: (9)

Most aftermarket ECU, are limited on there outputs to 4a, that is where I came up with that number.


Are you running two relays from the same trigger?

Biggiesacks

Yah i want to run two relays off the same output. basically what im trying to do is tap the relay that triggers the high voltage resistor bypass for the fuel pump, to trigger my own hard wire bypass. Thus preserving the factory low/high voltage functionality while also having my hardwire bypass there to augment it in high voltage operation. I posted about it in over in the engine sub forum in mrfreds hardwire thread.

TheBoz

iTrader: (9)

In the fuse box under the dash, there are two relays there, that if I remember correctly control the high low fuel pump.


You should also be able to ditch the big fuel pump relay in the engine compartment.


When I did my double pumper, I a also supported the High/Low on pump one. I moved all the relays and resistor box to the trunk. It was not pretty, I will see if I can track down some pics.

Biggiesacks

for now i want to leave the stock system intact, but augment it with another relay to supplement the stock wiring. Ultimately I want to install a synchronous buck/boost converter to remove the factory resistor and allow me to tune the fuel pump voltage for optimal rail pressure at various injector duty cycles.

TheBoz

iTrader: (9)

You could build your own PWM controller and use some hella SSR's. I just converted my car to SSR for the fuel pumps. I am on a standalone so it already outputs the PWM signal. But you could build an Arduino to take a boost ref and rpm signal or fuel rail pressure, and then build a 3d PWM map for your fuel pumps.


The SSR's are rated at 22amps and have a peek ingress of like 30 or 35 something like that.


Here are the relays that I am using:

Biggiesacks

This is very close to what i plan to do. Using a micro controller to read injector pulse width with a fuel pressure error correction method seems like the right way to do it. The micro controller could then set the voltage to the fuel pump via a buck/boost power supply. I guess it would be something of a closed loop fuel pressure management system. I haven't really looked into what kind of hardware is available for monitoring fuel pressure at the rail though. As far as programming the micro it would be kind of the same as boost control is done. You set up a base table that hits your fuel pressure targets but also has error correction via readings at the rail.