Fitech 600 Fuel Pump wiring

[stevant]

So I had a bunch of questions which I think I’m slowly starting to answer and work out but the fuel pump wire hook up is hanging me up. They state it needs to go to the positive side of the relay but not sure what side that is. I also need to cut the jumper?

Any help would be appreciated.

91701

[brewha]

I’ll give this a shot. It’s been awhile since I’ve seen behind the fuse box. The relay has 2 circuits a main power supply to the pump and a switch that controls the relay. Where the 2 wires are connected in the same plug in your picture is the power coming into the relay for both circuits. The heavier wire is main power supply for the pump and the smaller tan wire is powering the relay switch. The black wire is the ground for the relay switch. In a non fuel injected system the power would hit both circuits at the same time and the relay switch would activate sending power to the pump.

For fuel injection, the computer will control the relay switch. To connect the computer, cut the smallest tan wire as close as you can to the V Where the power is currently coming into the relay. Then connect you computer EFI fuel pump wire to the smallest tan wire you just cut away from the power supply. The Efi wire will power the relay switch.

The Fitech 600 could be connected directly to the fuel pump but for me it was easier and cleaner to use the RF harness and use that Fitech wire to control the relay switch in RF fuse box.

Hope I didn’t make you more confused...see picture below.

91715

[Boydster]

Because of PWM (pulse width modulation... a feature FiTech uses to prevent running the pump at 100% all the time), you cannot use a relay to power the pump. Make sure you have a PWM friendly pump. Walbro's are not. Even Walbro says on their website that their pumps will quickly fail when used with PWM.

I cut the tan wire (that runs from the relay to the pump) behind the dash. Then ran my fuel pump power wire out of the Fitech and spliced it right into the cut tan powering the pump. Then I was able to re-purpose the fuel pump relay for something else.

I'm still go-carting, but it's working great so far. I'm running an Aeromotive Stealth 340, good for use with PWM and very, very quiet.

[stevant]

I do have a Walbro too and do not want to pull that out prematurely due to my error. When speaking to Fitech they mentioned I could attach it to the positive side of the relay connection but seems like I shouldn’t. Do one of those wires coming out of the fuse panel go back to the fuel pump? Any reason I cannot pick up that line after the relay, bypassing it? I still want the inertia switch to do its job so I guess since that ground is still active all should be ok.

Just trying to see if I can pick up that wire to the pump at the fuse panel. Please excuse my electrical ignorance if I suggest anything crazy. See the pic below, that wire goes directly back to the fuel pump. Can’t I just connect to that wire my finger is on bypassing the relay?

91723

[brewha]

The PMW is set able from the hand controller. It can set to 100 and that nullifies it’s use. Using the Fitech wire to control the relay switch allows you to use almost any fuel pump including walbro. I believe my pump is a walbro or a clone brand.

Either way you go, make sure you wire the inertia switch into the main power line feeding the pump to prevent a upside down barbecue.

[brewha]

Just saw your post......connect the Fitech wire to the wire you cut in the fuse block. That’s why you need that small wire as long as possible. It’s not easy soldering such short wire but is do able. Then your inertia switch is in line if you are using the RF diagram. The reason you want a relay switch is to handle the surge when the pump turns on.

[edwardb]

I do have a Walbro too and do not want to pull that out prematurely due to my error. When speaking to Fitech they mentioned I could attach it to the positive side of the relay connection but seems like I shouldn’t. Do one of those wires coming out of the fuse panel go back to the fuel pump? Any reason I cannot pick up that line after the relay, bypassing it? I still want the inertia switch to do its job so I guess since that ground is still active all should be ok.

Just trying to see if I can pick up that wire to the pump at the fuse panel. Please excuse my electrical ignorance if I suggest anything crazy. See the pic below, that wire goes directly back to the fuel pump. Can’t I just connect to that wire my finger is on bypassing the relay?

91723

The sole purpose of the relay in the RF fuel pump circuit is to enable the inertia switch. If the relay is bypassed the inertia switch is out of the circuit. Can't have it both ways. The inertia switch is on the black ground wire pictured.

Inertia switch closed = relay grounded, relay energized, fuel pump receives +12V through the relay.

Inertia switch open = relay not grounded, relay not energized, no voltage to the fuel pump through the relay.

I suspect this isn't compatible with PWM. But I don't know that for certain.

[stevant]

So to clarify, I’m cutting the small wire closest/connected to the large wire at the fuse panel, then connecting the Fitech pump wire to that small wire. I assume I would then let the Fitech tell the fuel pump what to do, when to do it and how much. Will the Walbro handle this as Boyd is saying the Walbro is not designed for this.

Am I on the right track here?

[brewha]

That sounds like the right plan. To get to the PMW you need to turn on pro calibration, it will then become visible. I believe I read on the Fitech website any thing 75 and up turns it off. 100 would definitely turn it to off.

This is how I’m running mine by the way.

[brewha]

Some added info here....the Fitech will send power on that line at pre iginition start to prime the fuel pump and when it senses rpm movement. If the engine is not turning over it shuts off power. Hence you will hear the pump shut off after prime pre start. It does not negate the use of the inertia switch though.

[stevant]

Ok, so the Walbro will be ok like this? By me setting the pro calibration it will function correctly with the Fitech? How do you know what setting to choose? We do want the Fitech to control the pump as intended not just set to 100? When you setvanove 75 does that negate control from the Fitech?

I was told that if you install after the relay you lose the inertia........

[DadofThree]

I've attached photos showing my wiring of the Fitech in my build. And can send you the pdfs if you wish. I moved the inertia switch to the rear by the fuel pump.

I skipped the relay (pulled the fuel pump fuse), cut the Fitech orange wire a lot shorter that the wire supplied by fitech and tied it into the tan wire (mine was a plug in near the fuse panel) that runs to the fuel pump.

4,500 miles and no problems.

Hope this helps,
Dave

https://farm2.staticflickr.com/1842/44128286662_1fd554dc25_b.jpg (https://flic.kr/p/2aet1dE)Fitech Close up 1 (https://flic.kr/p/2aet1dE) by D. R. (https://www.flickr.com/photos/annabellerose/), on Flickr

https://farm2.staticflickr.com/1857/43458158514_e0d5efcedd_b.jpg (https://flic.kr/p/29dfqt5)Fitech Close up 2 (https://flic.kr/p/29dfqt5) by D. R. (https://www.flickr.com/photos/annabellerose/), on Flickr

https://farm2.staticflickr.com/1840/43270739995_e0222cd537_b.jpg (https://flic.kr/p/28VFRti)Fitech Close up 3 (https://flic.kr/p/28VFRti) by D. R. (https://www.flickr.com/photos/annabellerose/), on Flickr

[stevant]

I used my “electric choke” power feed out of the ignition for the White wire going to the Fitech, was not using that. That does get power in the on and crank position. Is that ok? Large “EFI or Coil” is going to the coil positive side .

Also on my negative coil is the blue wire from the Fitech and the purple tach wire from the RF harness since I’m using no ignition box.

[edwardb]

I was told that if you install after the relay you lose the inertia........

Post #7 is how it works. Really. :p

[phileas_fogg]

Don't cut anything yet!

I have a Holley system, but the fuel pump wiring is identical in function to FiTech. Your FiTech system provides +12V to the fuel pump. The easiest way to get that +12V where it belongs is to unplug the weatherpak connector in the Ron Francis fuel pump circuit (tan wire) and connect the FiTech fuel pump feed (orange wire) to the “down stream” weatherpak half. That allows you to use the Ron Francis wiring to get power from your EFI fuel pump circuit to the pump itself. Note that in the picture below, the Holley fuel pump wire is green.

https://farm5.staticflickr.com/4305/35484361273_1d97e01668_z.jpg (https://flic.kr/p/W4CCmi)IMG_3356 (https://flic.kr/p/W4CCmi) by jhsitton (https://www.flickr.com/photos/91016165@N07/), on Flickr

To use the inertia switch, remove it from the Ron Francis harness and splice those RF wire ends together.

Next splice the inertia switch into the FiTech fuel pump feed (orange wire). Note that in the picture below, the Holley fuel pump wire I used is black.

https://farm5.staticflickr.com/4316/35484362533_6a83591c93_k.jpg (https://flic.kr/p/W4CCJ2)IMG_3349 (https://flic.kr/p/W4CCJ2) by jhsitton (https://www.flickr.com/photos/91016165@N07/), on Flickr

Note that the inertia switch wiring shown above is WRONG! The wires should be connected to the two out-board pins of the connector; the center pin is not used. If your switch looks like the one in the picture, double check its operation with an ohm meter before installing it, and correct if necessary. See this thread (https://www.ffcars.com/forums/17-factory-five-roadsters/538706-fuel-pump-wiring-question.html) for details.

You can leave the hot end of the Ron Francis weatherpak just hanging for now; if you decide to use that circuit to power something else, you've got the connector in place. If you don't use this circuit, pull the fuse and put some electrical tape over the weatherpak to keep the smoke where it belongs.


John

P.S. Be sure to set your FiTech computer so that is does NOT provide PWM voltage to the fuel pump!

[brewha]

There are many ways to do it. The easiest is to cut the wire and connect Fitech fuel feed to it and your done. No moving of the inertia inertia switch is needed (as Edwardb has pointed out). Just check the PMW and you should be good.

My 2 cents....
Relays are there for a reason... pump motors draw excessive current at start up. I would rather have to check a fuse or a relay then debug a computer in the fi system to find out a circuit is cooked.

[Boydster]

Just getting back into this... Yes, I should have also advised that you can turn the PWM off and FiTech says you can then run the relay and inertia switch. Brewha gave you good info on doing that... Pro tuning, Fuel pump control, Then I believe there's 3 PWM settings... set them all to 100 and the pump will run full time as long as the engine is turning.

I should clarify that Walbro has said PWM is not compatible with certain pumps. Please do the research and see if your pump is or is not PWM capable.

However, as others have said, FiTech PWM (which operates at 1khz) does not work with mechanical relays. It may work with certain solid state relays, but thats a whole nother box of rocks.

[OnlyAndy]

I ordered the EFI option on my 33' kit with intention of using a Fitech on a small block Chevy. I assumed it would be a calk walk... Now I'm not so sure. This sounds a bit complicated. Do the other brand EFI conversions have the same wire/fuel pump issues?? Stewart tells me they hope to pick up at F5 Sat or early next week. Then couple weeks out here to SoCal so I still have time to change plan.

[brewha]

The two current popular brands for EFI are Fitech and Holley. Both are great kits. Both kits are simple to set up. What makes them complicated is how we as owners try to implement them. These kits work with most fuel pumps. The PWM option mentioned here is that... an option. If you have a fuel pump that can handle it, then you can use it. You can also just run the fuel pump under full power all the time and the EFI unit will regulate its own pressure. The Ron Frances wire harness is pretty well documented but can be confusing when connecting to an EFI due to each engine configuration being different.
The documentation for both EFI’s and wire harness are written in a way to cover many different motors, electrical systems, types of timing, and fuel systems to meet our needs. We are left to interpret how that is to be done with our engine and wiring layouts.
It sounds complicated, but it took me only 4 hours to have mine up and running. Know what you have ,read well, and make a plan. I learned a lot from the people here who went before me.

[OnlyAndy]

Thanks for this reply. If YOU say it can be done, that is good enough for me. I won't worry about it until I have too.

[stevant]

Thank you all for your help and advice, as always it's appreciated!!