Coyote/F5 wiring harness connections

[vern smith]

We are having trouble getting the Coyote Gen 3 electronics integrated with our F5 MK 4 roadster harness. We are looking at the Ford install manual for the 2018 Coyote 5.0L manual trans. We are using the ignition switch that came with the F5 harness. Our problem is getting the starter solenoid energized. The Ford manual seems to be saying we should have 12v at the fuel pump with the ign switch in the ON position as well as the start position. What is surely a related issue the starter solenoid relay will not engage the solenoid. The problem is not the solenoid, we connected the solenoid pins under the relay and the solenoid energizes. Whatever PCM signal the starter solenoid needs is not being sent by the PCM.

The Ford instructions tell me using the PCM start is optional, but I would like to use it, if for no other reason than I paid for it. My helper’s reading from the Ford install manual does not think the 12v should be seen at the fuel pump with the ign switch in the on as well as the start position. From my read it looks like it does.

Any suggestions will be appreciated.

Vern

[Sharris2]

It's my understanding that ford has always had 12 v at fuel pump with ign on, this is why they have an inertia switch in case of accident to shut power down.

[michael everson]

Really just 3 connections will get it running. Green to the fuel pump, light blue to blue EFI wire and light green to any ignition source but use t either the choke wire or orange EFI wire. Also you will need to run a large red wire from a battery source to the power distribution box as stated in the instructions.
Mike

[Al_C]

Mike hit it on the head. Just to reinforce what he wrote, when he says "green" or "light green" or "light blue" he's referring to the coyote pigtail wires. The fuel pump will engage as soon as you turn the ignition on. In my opinion, you want that.

I'm curious about your starter. I don't know any coyote users that have a separate starter solenoid. You should let the coyote pcm control the starter with its start wire (lead "N" from takeout CCA on the controls pack instruction sheet) If you have wired the ignition switch as Mike recommends, you'll use the coyote clutch safety switch and the the blue RF starter wire won't be connected. In that case, the coyote start wire takes it's place on the starter/solenoid.

[edwardb]

Mike's information is correct for the Coyote pigtail:

Coyote Green Fuel Pump Relay Out -> Ron Francis Fuel pump circuit. Tap into the RF panel per the Factory Five instructions

Coyote Light Blue Starter Motor Request (SMR) -> RF harness Blue EFI Crank Power wire. You can either diet out balance of RF blue start wires, including RF clutch safety switch, or just tie out of the way.

Coyote Light Green Ignition Relay Trigger -> RF ignition switched wire. Both choke or orange EFI work. I've done both. Use whichever you don't need elsewhere. Just confirm have +12V with ignition on in both run and start.

Other connections required: Coyote cooling fan wire to the radiator cooling fan, Coyote starter lead ("N" as described above) directly to the small post on the starter solenoid. The large post should have direct +12V from the battery. No separate firewall starter solenoid should be used as mentioned. +12V battery power to the PDB through the provided 250amp fuse. Grounded per Ford Performance instructions. Clutch safety switch installed and confirmed working. Should close with the clutch pedal fully down. The one from the Ford Performance control pack. Not the Ron Francis one. DBW (accelerator pedal) installed and confirmed working. When you turn the key on, you should hear the stepper motor in the throttle body initialize and then move when the accelerator pedal is moved. Balance of connections completed per instructions including PCM.

With the above connections, the Coyote should start. Has for me every time. Key points: If something isn't wired properly, good chance the PCM won't initiate the starter sequence. It's smart that way. Make sure you're pressing down on the clutch pedal and the Coyote bottom clutch switch is closing. Won't start without that. When you first turn the ignition key to on, you should hear the fuel pump run briefly to pressurize the system. Not continuously. If you don't hear that, something is wrong. Likely something with the wiring. Make sure the inertia switch button is pushed down. With the key moved to start, starter motor should spin and should start. Note for the first start you may need to crank it longer than usual to get the fuel flowing. Pretty common. You should also be checking the fuel pressure and adjust to the PSI listed in the Ford instructions.

[vern smith]

I appreciate the help, We have fuel pressure and the starter is engaging. Problem is the fuel pump is turned on by the F5 fuse/relay rather than the Ford PCM and the starter solenoid is engaging from the F5 harness rather than the Ford fuse/relay. However it's working. The PCM is recognizing the ign switch when turned on because the throttle body flips open and closed and the throttle body is following the throttle pedal positions. As long as all the other needed signals from the PCM are forthcoming I'll leave it like it is. I'm not particularly comfortable with this set up.

[edwardb]

I appreciate the help, We have fuel pressure and the starter is engaging. Problem is the fuel pump is turned on by the F5 fuse/relay rather than the Ford PCM and the starter solenoid is engaging from the F5 harness rather than the Ford fuse/relay. However it's working. The PCM is recognizing the ign switch when turned on because the throttle body flips open and closed and the throttle body is following the throttle pedal positions. As long as all the other needed signals from the PCM are forthcoming I'll leave it like it is. I'm not particularly comfortable with this set up.

A little confused by your response. Are you breaking into the Ron Francis fuel pump circuit like shown in the Factory Five Coyote installation instructions? The power comes from the Coyote system, but uses the Ron Francis relay + inertia switch + wiring back to the fuel pump at the tank. Wired that way, the Coyote PCM controls the fuel pump. As far as the starter, if you don't use the Ron Francis blue starter wire to the solenoid and instead use the Coyote starter wire, the PCM totally controls the starter. it's one or the other. Pretty straight forward.

The Ford Performance instructions are important IMO. But should be used in conjunction with the instructions from Factory Five. I assume you have those too? https://www.factoryfive.com/wp-content/uploads/2021/12/Coyote-Gen-3-Fitment-roadster-rev-1F.pdf.

Is the engine starting?

[vern smith]

[QUOTE=edwardb;481104]A little confused by your response.

Me too, :) I think some of the trouble started with the F5 harness which has the two blue wires connected to a single terminal labeled start on the F5 schematic. We separated them leaving one on the start terminal and the other attached to the "on" terminal. That fixed the fuel pump which is now under the PCM's control. The Ford connection to the solenoid still is not working. Another issue, this may be normal but the accelerator pedal is working strangely. When you turn the key on the throttle butterfly cycles and buzzes then goes quiet. If you depress the throttle pedal all the way down (floor it) and hold it for a second or two then return it to idle the butterfly will buzz and follow movement and will continue to do so until you leave it at idle for several seconds at which time the buzzing will stop. To get it to work again you have to repeat the first sequence. Floor it, hold for a second or two then return to idle. If you do not go to the floor again, no buzz and no butterfly movement.

We have something screwed up because the Ford solenoid lead is still dead. We checked the fuse and checked for voltage at one side of the relay. For some reason the relay is not getting the signal to close from the PCM. The alternate hookup using the F5 wiring works fine.

[edwardb]

Me too, :) I think some of the trouble started with the F5 harness which has the two blue wires connected to a single terminal labeled start on the F5 schematic. We separated them leaving one on the start terminal and the other attached to the "on" terminal. That fixed the fuel pump which is now under the PCM's control. The Ford connection to the solenoid still is not working. Another issue, this may be normal but the accelerator pedal is working strangely. When you turn the key on the throttle butterfly cycles and buzzes then goes quiet. If you depress the throttle pedal all the way down (floor it) and hold it for a second or two then return it to idle the butterfly will buzz and follow movement and will continue to do so until you leave it at idle for several seconds at which time the buzzing will stop. To get it to work again you have to repeat the first sequence. Floor it, hold for a second or two then return to idle. If you do not go to the floor again, no buzz and no butterfly movement.

We have something screwed up because the Ford solenoid lead is still dead. We checked the fuse and checked for voltage at one side of the relay. For some reason the relay is not getting the signal to close from the PCM. The alternate hookup using the F5 wiring works fine.

If you follow the Ron Francis schematic for those two blue wires from the ignition start switch post, one is LT BLU-EFI CRANK POWER. That’s the one you should connect to the Coyote pigtail Light Blue Starter Motor Request (SMR) and is the signal to the Coyote PCM to spin the starter. The other Ron Francis LT BLU-NS SW-START SOL is NOT USED when wiring the Coyote to have the PCM control the start. Whatever you have it attached to, remove it. You can take the wire out completely or tie it out of the way. Sounds like you may it attached to the Coyote pigtail Light Green Ignition Relay Trigger? If so, that won’t work because it only has +12V when in the start position. The Coyote wire needs +12V all the time, e.g. whenever the key is on. It won’t start, run, or act normally without that constant +12V. Even mentions that in the Ford instructions. Use the Ron Francis choke or orange EFI wires as I mentioned previously.

I don't understand the change you described to make the pump work. You should only have the Coyote fuel pump wire spliced into the Ron Francis fuel pump circuit as shown in the Factory Five instructions. No other wires or connections are required. Not sure how you're confirming that it works. As I said previously, when wired and controlled by the Coyote PCM, the pump only runs briefly (maybe a second or two) when the key is first turned on. The PCM turns it on continuously when the engine is started and running. Note that after the fuel pump runs briefly when first turning the key on, if you turn it back off and immediately on again you won't hear the pump. There is about a 10 second delay before the system will power the pump again. If you listen closely, you can hear the relay in the PDB close after the 10 second delay. For "normal" operation, this isn't noticed because typically you go from on to start, the engine starts, and the PCM turns on the pump. But while wiring and testing, some interpret this as something wrong. There isn't.

The only wire you should have on the small post to the starter is the Coyote harness start wire. Nothing from the Ron Francis harness.

I'm assuming you have the Ford clutch safety switch installed and confirmed working. Should close with the clutch pedal fully down. The one from the Ford Performance control pack. Not the one on the Ron Francis LT BLU-NS SW-START SOL wire which is not used in your setup as mentioned previously. The Coyote PCM is controlling the start. The system will power up and the fuel pump run (briefly as described) but the engine won't crank unless the clutch pedal is pushed down.

I can't explain why you may (or may not) have intermittent operation of the throttle body. Could be because the wiring is wrong. Guys have had occasional Coyote problems with bad grounds. But first things first. Make sure the wiring is exactly as I've described above. Which BTW is exactly how both the Ford and Factory Five instructions describe.

Good luck. When wired exactly as described, it should work. I've done several and they started almost immediately on the first try. Mike (who also responded in this thread) has done dozens. At some point, with all due respect, if you can't figure it out, you may need to get some outside help.

[vern smith]

Thanks for the help, we got it now.