This is the setup I am currently using with the SDS setup. It powers both the coils and injectors in start position without any issue. I do like Nocarrier's Fuse Block Relay, I may elect to go to this type of fuse block.
Looks much neater.

http://forums.pelicanparts.com/uploa...1483890181.JPG

Great info. I'm probably going to do an MS3Pro on my next build on an '87 EFI conversion. I'm looking at my workshop manual wiring schematic for a Model 88 and trying to follow your diagrams. For 12v key on trigger you show coming off fuse #11 which I think is a 16A fuse supplying the hazard light and backup light switches? Your fuel pump 1 &2 relays I'm assuming are two new relays and the old pump relays are not used at all? I've been studying these workshop schematics for both a '79 and an '88 for a few hours and my head is spinning. What wiring CAD software did you use? Thanks.

Hey Boosted79

You are correct. The actual fuse number is 8. It is a 16A fuse. It is tied to fuse number 7. It's wired to the fuel pump relay, control unit blower, speed relay, ignition transformer, & air conditioning operation relay. See attached wiring diagram. Diagram is from an 88 930.
I had originally done the fuel pump relay split with my SDS setup. My plan is to retain the original relays, I don't want to mess with the original wiring too much.
I used Revit to draw the diagrams. Autocad would work as well.

Regards

John

http://forums.pelicanparts.com/uploa...1483927242.JPG

OK. In the diagrams in post 96,97,98,106 you show the 12v supply to fuse #8 (#11 in your diagram) as coming directly off the batt so it would be constant 12v, not switched 12v. I think you want it to come off the switched side of the ign. sw, so it would come off a 2nd line off the ign. sw, like you show in #107 for the injectors?

Hi All

I have deleted all the previous wiring diagrams, and will be updating them.
Please stay tuned.

Regards

John

You can use one relay to trigger both relays in the trunk for the fuel pumps.

Why a fast idle valve? I'd run a three wire bosch idle valve with the pwm outputs.

Widebad should go to same ground as everything else.

You don't need a relay for the wideband. Power it from your fuse block controlled by your main relay.
It looks like it's wired to disconnect when the key is positioned from acc to start.

Don't forget cam sensor and boost solenoid...

I'm on my phone and it's hard to see all details so I'm not sure if I've missed anything. I'll check later when I get to a computer.

Thanks nocarrier for the input.

I did the fuel pump split mod, a couple of years ago. I provided a separate 12v feed to each fuel pump relay. I thought it would be safer to have 2 relays controlling the feed from the battery. How would a single relay work with the 2 feeds?

I got the 2 wire fast idle valve from the local wreckers for cheap. I do have a 3 wire bosch idle valve. My plan is to install it once I get the car running.

The wiring of the wideband was based on the AEM installation instructions.
Makes sense to simplify the wiring.

I am hoping to get diagrams up dated tomorrow night.

Thanks again.

John

Just use one relay and split the signal to the coil trigger terminals to the fuel pump relays up front. The original wiring provided a +12volt signal to the fuel pumps when the sensor plate was depressed on the cis systems. Use a relay to switch from the ground signal from the megasquirt to +12 and feed that back into the original circuit that triggered both fuel pumps.

When you seperated the relay circuits you dont need to isolate the trigger level inputs just the high amp switching circuits. That way both relays activate with one signal.

Is it still necessary to run two pumps if you upgrade one?

I've been looking at these brushless spur gear pumps from XRP and it seems like one would do the job mounted up front behind the fuel tank. 120 gph @ 95psi on 13.5Vdc

https://scontent.cdninstagram.com/t5...NjcwMw%3D%3D.2

If 1 pump is enough, then 2 are not needed.

i have always been a big fan of one. if, and when,you loose a pump on a 2 pump system there is a couple nano seconds before all the safety bells and whistles kick in.a tow will always be cheaper than an engine. aeromotive a-1000 and call it a day

Hey nocarrier

Could you post a sketch of what you had in mind for the fuel pump wiring? Having trouble visualizing it.

Thanks

John

Hi Guys

Here are my latest wiring diagrams.

ECU

http://forums.pelicanparts.com/uploa...1484099587.jpg


Regards

John

Injector Wiring

http://forums.pelicanparts.com/uploa...1484099726.jpg

Coil on Plug Wiring

Where is the best place to ground the coils? Pin16 White Connector, Battery, or Engine block? Manual says engine block.
Also because I am twinplugged I plan on split the 5V signal to the lower corresponding cops, does this sound reasonable?
What amperage fus should I be running for the coils?

http://forums.pelicanparts.com/uploa...1484099784.jpg

http://forums.pelicanparts.com/uploa...1484099808.jpg

Splitting the 5v signal to two COPs will double the amps thru the MS3 ignition trigger circuit. You'll have to find how many amps the Denso's draw thru the the trigger side and determine if the MS3 Pro will handle double that.

All grounds should go to the same spot on engine block not battery. A very good spot is where the air pump was located

So just to clarify. Coil on Plugs, Injectors, and Fast Idle Valve should be grounded to the engine block? All sensor grounds should be grounded to sensor return wire?

Thanks

John

Yes that's correct. Can't remember with the idle valve. I've done 4 930s to ms but can't remember.let me look at some notes I made. Want to say ground with sensors. Getting old sux

I will be going with 3 wire Bosch Fast idle valve. I assume no relay is required.