Megasquirt - a story of injection

[Husky65]

Yeah so I'm using 4 relays instead of 2 disregarding the fan. I wasn't sure one relay would be enough for everything. Plus I thought separating the coils/injectors/sensors may eliminate some noise. Im happy to reduce the number of relays to 3, as I still have an AC relay I want to add

[Husky65]

Even happy to go to 2 relays of the noise thing is negligible

[Husky65]

Sorry to bombard you fellas
Here is another, using my current fuel pump feed as a ground and putting a fp relay in the boot for less voltage drop.

[hybrid]

AC on output?
A thermostat should control ac, not ms.
You can send a signal to the ms when ac turns on so ms raises the idle a bit. Is that what you mean?
Or is that to cut out the ac on high load?

[Husky65]

Yup, the AC will go through the thermostat, to the input on the MS. The MS will then control the output to the AC compressor itself. It's so I can have it switch off under wot and certain other conditions.

[boofhead]

1 main relay
1 main fuel pump relay
1 extras relay

then add relay for extra pump

main fuel pump relay also powers the coils in extra ignition on relays

fan relays are separate

I like to keep it below 20 amps for a 30 amp relay limit to 15 amp preferred.

[boofhead]

Grounding scheme used is a huge noise control factor as well as how you run the wires.

[Husky65]

1 main relay
1 main fuel pump relay
1 extras relay

then add relay for extra pump

main fuel pump relay also powers the coils in extra ignition on relays

fan relays are separate

I like to keep it below 20 amps for a 30 amp relay limit to 15 amp preferred.

So, with the fuse box I'm running, 1 relay for the ecu, 1 relay for the fuel pump/injectors etc, and 1 relay for the coils should be fine?

[Husky65]

Grounding scheme used is a huge noise control factor as well as how you run the wires.

Yeah my car is grounded pretty well, I have grounds coming out of my eyeballs. I will be sure to ground each item as best as I can.

[boofhead]

1 main relay
1 main fuel pump relay
1 extras relay

then add relay for extra pump

main fuel pump relay also powers the coils in extra ignition on relays

fan relays are separate

I like to keep it below 20 amps for a 30 amp relay limit to 15 amp preferred.

So, with the fuse box I'm running, 1 relay for the ecu, 1 relay for the fuel pump/injectors etc, and 1 relay for the coils should be fine?

keep pump on its own relay - ign plus inj on extra relay

[boofhead]

Grounding scheme used is a huge noise control factor as well as how you run the wires.

Yeah my car is grounded pretty well, I have grounds coming out of my eyeballs. I will be sure to ground each item as best as I can.

no - how you ground sensors and the ms

[hybrid]

Grounding scheme used is a huge noise control factor as well as how you run the wires.

Yeah my car is grounded pretty well, I have grounds coming out of my eyeballs. I will be sure to ground each item as best as I can.

no - how you ground sensors and the ms

Yes, very important.
Here's a good forum thread on the subject.
http://www.msextra.com/forums/viewtopic ... 01&t=66921

[Husky65]

Grounding scheme used is a huge noise control factor as well as how you run the wires.

Yeah my car is grounded pretty well, I have grounds coming out of my eyeballs. I will be sure to ground each item as best as I can.

no - how you ground sensors and the ms

Yeah that's what I meant.

[Husky65]

Yes, you can use a cam sensor from a later model windsor (I've got one in mine just to block the dissy hole and drive the oil pump).
And yes, the injector wiring is definitely different if you're running sequential fueling.
In batch fire, there are two injector channels, so you would wire up 4 injectors per channel.
With sequential, you will run 8 separate injector wires - one to each injector.

Going back to this.

If you had 4 injector channels instead of 2, and had dual widebands, would you wire them up as a bank, or opposing.

Ie, Channel 1 = Cylinder 1,2, Channel 2= 3,4 Channel 3=5,6 etc,
As this would allow the ecu to adjust that banks afr only, without changing the other banks afrs.

Or would you do it in opposing firing order pairs, ie Channel 1 = 1,6 - Channel 2 = 3,5 - Channel 3 = 7,4 etc.
With dual widebands, it seems the ecu would not be able to correctly adjust afrs per bank with this method.

I guess what I'm asking is does fuel injected into a cylinder when it is not on the firing order have any affect on AFR's of that cylinder?

[Dwayne]

My edelbrock pro-flo uses 4 injector channels to fire with the 351 firing order: 8/4 2/7 1/3 5/6