[HWYSTR455]

Originally Posted by 1972 Formula 400

Got the throttle body installed and waiting on some last few fittings to show up to complete the install and get it fired up. I have all the wiring hooked up except for the switched 12v that needs to be "hot" in crank and run. Any body know a wire to look for that will be hot in crank and run? That's the only thing that I am questioning right now. So, any guidance would be appreciated!! Thanks

Have an HEI conversion wire for the coil/distributor? If so, the coil wire should work. If not, you can tap into it where it goes into the firewall.

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[1972 Formula 400]

Originally Posted by HWYSTR455

Have an HEI conversion wire for the coil/distributor? If so, the coil wire should work. If not, you can tap into it where it goes into the firewall.

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All I have is the power conversion wire going to the positive terminal of the distributor and my tach wire from the distributor. From some research it should work. Will let you all know

[lil65gto]

1972, I have the Fitech efi600 (with an inline pump below the tank) and have been plagued with hard start issues for almost a year but I finally got it figured out. Just an FYI for ya...make sure that switched hot lead (running your pump) is a solid 12 volts! Check for any drop in voltage as well when you crank the engine over too. That was my problem all along. The car was awesome when I finally got it started but getting it started was a nightmare. The last tow home was the deal breaker...it was going to be fixed or a carb was going back on.
I had my switched wire spliced into the ignition switch but come to find out it wasn't giving me a solid 12v. Mine was showing roughly 10.5 volts when key switch was 'On' and dropping to 5-6 volts during 'Cranking'. So after fighting with it trying to find a solid switched 12v, I ended up installing a toggle switch from the Batt terminal of the fuse box. Problem solved and life is awesome. Love the fuel injection now...

[1972 Formula 400]

Originally Posted by lil65gto

1972, I have the Fitech efi600 (with an inline pump below the tank) and have been plagued with hard start issues for almost a year but I finally got it figured out. Just an FYI for ya...make sure that switched hot lead (running your pump) is a solid 12 volts! Check for any drop in voltage as well when you crank the engine over too. That was my problem all along. The car was awesome when I finally got it started but getting it started was a nightmare. The last tow home was the deal breaker...it was going to be fixed or a carb was going back on.
I had my switched wire spliced into the ignition switch but come to find out it wasn't giving me a solid 12v. Mine was showing roughly 10.5 volts when key switch was 'On' and dropping to 5-6 volts during 'Cranking'. So after fighting with it trying to find a solid switched 12v, I ended up installing a toggle switch from the Batt terminal of the fuse box. Problem solved and life is awesome. Love the fuel injection now...

The toggle switch off the batt terminal was my other thought.

[Scott65]

Originally Posted by lil65gto

1972, I have the Fitech efi600 (with an inline pump below the tank) and have been plagued with hard start issues for almost a year but I finally got it figured out. Just an FYI for ya...make sure that switched hot lead (running your pump) is a solid 12 volts! Check for any drop in voltage as well when you crank the engine over too. That was my problem all along. The car was awesome when I finally got it started but getting it started was a nightmare. The last tow home was the deal breaker...it was going to be fixed or a carb was going back on.
I had my switched wire spliced into the ignition switch but come to find out it wasn't giving me a solid 12v. Mine was showing roughly 10.5 volts when key switch was 'On' and dropping to 5-6 volts during 'Cranking'. So after fighting with it trying to find a solid switched 12v, I ended up installing a toggle switch from the Batt terminal of the fuse box. Problem solved and life is awesome. Love the fuel injection now...

Relays are your friend on getting good voltage to the fuel pump.

[lil65gto]

Originally Posted by Scott65

Relays are your friend on getting good voltage to the fuel pump.

I actually tried that before going with a toggle (I hate toggles). I spent 3 solid nights trying to get switched power before I threw in the towel.

[Scott65]

Does your efi send positive 12v to the pump, or ground? Mine grounds the pump to turn it on. Takes a little creativity in wiring, especially since I wanted to be able to manually run the pump as well, but it can be done. Those toggle switches can give out handling full voltage continuously over time.

[lil65gto]

Originally Posted by Scott65

Does your efi send positive 12v to the pump, or ground? Mine grounds the pump to turn it on. Takes a little creativity in wiring, especially since I wanted to be able to manually run the pump as well, but it can be done. Those toggle switches can give out handling full voltage continuously over time.

Yes, I do believe so. I did go with a HD toggle to handle this (not the $5 Autozone specials). The only reason I mention it is to ward off any issues that 1972 Formula 400 may have with switched power. I was ready to rip my hair out...

[Scott65]

Another option is to add a small accessory fuse block, wire it full time hot, then run to switched relays from there. A lot of these old cars don't have enough fuse capacity for modern accessories anyway...

[1972 Formula 400]

I have 2 heavy duty toggle switches on the dash already that are hot all the time and a true 12 volts. One is for my electric fans and one is for my A/C clutch. I think I may use the one for the A/C clutch because the air conditioning does not work, the system bled down 5 years ago while it sat for the winter and we just plain never used it! I would rather run with the windows down anyhow. So the air-conditioning is going to get removed probably this next winter to free up some space under the hood. So I'm thinking I will just use that existing switch.

[1972 Formula 400]

Finished routing and plumbing all of the fuel lines last night. Just have to hook up the tach wire, the "hot" 12 volts wire, new throttle cable, install the water temp sensor, drill and install the O2 sensor, and run the handheld wiring into the interior and then double check everything and fire it up! Will keep you all updated.

[1972 Formula 400]

Checked voltage at the hei wire and it is 12.8 volts in run and drops to 10.6 volts while cranking. Is this too low of a drop? Fitech says this is the wire they normally use. Let me know your thoughts, thanks

[convgto]

lil65gto, I am running fitech with inline pump below the tank also, what relays did you use and can you tell me how you ran it. thanks Ken

[lil65gto]

Ken, I don’t believe I ran any relays with this system. I only used what was supplied with the Fitech wiring that I received. The only addition I did make was to add an auxiliary fuse block that worked off from my ignition switch, as I didn’t have any accessory fuse spaces (only 12v constants).

The problems I had that I finally resolved was the fuse block I installed was tied into my ignition switch for switched power. When I rolled the engine over, I was only getting 10v and less. Sometimes my readings were as low as 2-3v. The white wire that runs the fuel pump was run to this fuse block so I wasn’t getting the power to the pump that was needed….thus creating a hard start issue. I spent many nights trying to resolve this problem with relays, trying to rewire into another location with 12v, etc. I ultimately ended up installing a HD lighted toggle switch directly off from the battery which cured my problems, even though I HATE toggle switches.

As far as running lines and pump, the pump and prefilter are right together, only separated by about 3” of fuel line (it’s tight back there between frame rails). Custom brackets were needed to hang to pump/prefilter and are suspended from the trunk floor (hated drilling those 2 holes). The pump/prefilter run parallel with the tank, slightly below it. The line comes out of the pickup and turns toward the driver frame rail before looping back around to the pump/prefilter and then loops up over the rear inside the passenger frame rail. I zip tied the feed and return lines together which run down the frame rail and pop up by the heater motor to feed the EFI in the back. Right when it makes the bend and goes to the EFI (the rear intake manifold area), I mounted the 2nd filter before it plumbs into the EFI.

The new problems I’m having now (within the last month) with this system is that at odd times (1 start out of 20), it will give me fits with starting. It will roll over and start for a very brief moment…then quit. It will eventually start but it can aggravating at times. Other than that…the throttle response is amazing!

I hope I answered what you needed...if not, I can take pics if need be.

[HWYSTR455]

I think your problem is the fuse block itself, as well as the regulator on the firewall. You should run the power wire from the regulator or horn relay to a relay for the pump, and use a switch source to close the relay. That way you won't see any voltage drop while cranking.

The starting issue sounds like it could be your power sources for the ECU and/or distributor. Both need 12v DURING cranking, so you probably need to find another source.

Yeah, post pics. But sounds like you have a wiring issue.

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[FrankieT/A]

I had a situation with my FITech with hard starting at times. Turned to be a weak signal from mag pick up in the dist. One of the things FITech told me was your tach needle should move during cranking and tells you if your pick up is putting out a signal. Nice little diagnostic tool...of course this is if you are using timing control.

[HWYSTR455]

Oh, and fairly sure you have to run a relay for the pump, you can't run that directly to the pump from the ECU. Never heard of an ECU being able to handle direct load for the pump or fans. But I'm not that familiar with the FITech.

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[HWYSTR455]

Ok, that's news to me:

Required Orange (Large) Fuel Pump circuit. This wire provides 12V to the fuel pump and connects to the positive (+) terminal
on the pump. No relay is required.


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[JLMounce]

Yup the FiTech has a built in fuel pump driver. It will handle both pulse width modulated and fixed flow pumps up to 340LPH. Beyond that you need a relay. With fan control you do need a relay with the FiTech.

[Mace1971]

I was also told by FiTech that a relay wasn't necessary for my 255lph pump but the FiTech pump wire looks pretty light to me...maybe 16-18awg? I'm going to give it a shot since I want to use PWM but may end up just adding a relay for peace of mind.