I understand what a Relay does.
With a Relay installed the FiTech system will not longer be able to control the Voltage to the Fuel Pump. I think I have read somewhere (possibly another FiTech thread here) that the FiTech system is able to limit the intake of fuel from the mechanical pump, similar to a fuel regulator, to the Command Center. This is done by controlling the voltage to the Command Center.
I haven't drove mine yet with the new welded ground. I'll report back tomorrow and let you know if my problem is fixed.. last resort before I send it back.
I understand what a Relay does.
With a Relay installed the FiTech system will not longer be able to control the Voltage to the Fuel Pump. I think I have read somewhere (possibly another FiTech thread here) that the FiTech system is able to limit the intake of fuel from the mechanical pump, similar to a fuel regulator, to the Command Center. This is done by controlling the voltage to the Command Center.
The FITECH system uses (PWM) Pulse Width Modulation to control the voltage that runs the high pressure EFI pump in either the command center, or frame mounted, or in tank pump. It can idle the pump when you don't need the full amount of pressure the pump can deliver by varying the voltage that the pump receives, which can help the pump run cooler. The pressure from the mechanical low pressure pump is regulated in the command center by a float system with a needle valve and seat. Just like a carburetor. I don't think it will work through a standard relay either. I was told to add a relay to help with a problem I was having with the sub harness melting. I guess I need to ask Bryce. But from what I've read the standard relay can't switch on and off fast enough to accomplish the PWM.
Was the wiring that melted the power to the pump, or did it feed power to the EFI controller which powered the pump? I haven't received mine yet, but wondering if the EFI needs a relayed full power so that it can then regulate the FCC.
Dustin,
Hope it's fixed for you.
Kind of sucks not being able to use the timing control, kind of defeats the purpose of paying extra for the power adder.
I'll be running a locked out duraspark distributor and hoping timing control works as I should be seeing 12 psi at 6k from an s trim.
Which dist are you running?
How are you running air fuel under boost? Is the Fitech recognizing it or is it easy to command wot air fuel?
Sorry for the questions, I have my Fitech, just haven't started install. Should be start this weekend and have done shortly after.
![]()
[/QUOte
the air fuel ratio's are great... under boost and at idle, way better than I could ever get my old blow thru carb to run.
Bump post - I got a dedicated ground installed and re-routed my fuel lines. Having the same cutout issues as others have posted. My IAC steps are high (10+) right now, but I haven't gone through the tuning steps Brian shared earlier. (thanks for that) Will report back, good or bad.Brian,
The TPS reading will zero out every time you key off and allow the EFI save. What you are trying to achieve is to be at idle at operating temp with the IAC position between 5 and 10. To achieve this follow the steps below.
1. Bring engine up to operating temp. (around 180)
2. On the handheld go to Dashboard
3. Observe the TPS, IAC Steps, and Coolant temp readings
4a. If IAC Steps is zero and RPM is above target slowly close primary throttle blade screw (1/8 turn at a time) till IAC Steps start to raise to target 5-10 range.
4b. If IAC Steps are anything above 10 slowly open the primary throttle blade screw (1/8 turn at a time) until IAC Steps lower to the target 5-10 range.
NOTE: If TPS reading is 1.5 or higher the EFI doesn’t think the engine is in IDLE so it will raise IAC as a follower feature. To reset TPS just key off an allow EFI to power off. When EFI has saved the handheld values will go blank.