RF Sending unit harness not needed?

[Brian76]

Need some help guys. I'm working on wiring the coyote. Following the Ron Francis instructions and FFR coyote build instructions. I'm at the point where I need to install and connect the Ron Francis sending harness. Its consists of (7) wires:

-Blue (Water temp)
-Light Blue (Oil Temp)-I don't think this one is used on a standard build. I have no sensor in the oil pan.
-Grey (Oil Pressure)
-Black (Ground 1)
-Black (Ground 2)
-Tan (Electric Choke)-Not needed w/ coyote
-Green (Fan Thermo wire)

I also have Vintage Gages and they came with Oil Pressure harness (Blk & White wires) with crimp on ring connectors for the sending unit studs and a Water Temp Harness with connector to sending unit.

Question #1- Since the vintage gages came with harnesses, do I need the Blue, Grey or black ground wires in the RF sending harness??

Question #2-Do I need to do anything with the Green Fan thermo wire if I'm going to let the Ford ECM control the fan via orange ford wire?

If the answers to #1 and #2 are NO...then can I eliminate the entire harness? I must be missing something obvious because I have not found any questions/comments like this.124672

[i.e.427]

We generally use the oil pressure wire and coolant temp wire, using the RF wires to the dash and then splice on the connectors to the SH gauges. We also usually leave the choke tan wire in the harness shrink tubing the end of it. You never know when you may end up needing a switched circuit in the engine compartment. Lastly, the fan can be wired a couple different ways with the Coyote. You can use the RF relay combined with the Ford Control pack wiring or wire to the fan directly from the Ford Control pack.

[Brian76]

We generally use the oil pressure wire and coolant temp wire, using the RF wires to the dash and then splice on the connectors to the SH gauges. We also usually leave the choke tan wire in the harness shrink tubing the end of it. You never know when you may end up needing a switched circuit in the engine compartment. Lastly, the fan can be wired a couple different ways with the Coyote. You can use the RF relay combined with the Ford Control pack wiring or wire to the fan directly from the Ford Control pack.

Thanks ie427. I'm electrically challenged so I'm trying to keep this as simple as possible. You recommend splicing the Grey RF oil pressure into the dash. I don't understand where you splice it to the dash since the grey wire goes to a multi pin connector in the RF harness. Same question for the Blue RF water temp wire...how and where do you splice it to the dash? What advantage does this give versus just using the pre-fabbed vintage gage harnesses?

I was going to pull the tan choke wire into the dash and store it for future use. The green wire I was not planning to use...again...trying to keep it simple. Thanks!

[i.e.427]

Your splicing the Speed Hut connector (cut a pigtail about 6" long) onto the wires behind the dash for the connection to the gauges. Both for the oil pressure and the water temp sensor wires. And remember, you're going to have to do that for the fuel level sender as well. Don't get me wrong, you can run the sensor wires that Speed Hut provides all the way, it's just that we don't do it that way. Back in the day, before the sensor wires were included in the Ron Francis harness for the front harness, that is the way we did it. Fuel sensor wire is still the same.

[Brian76]

It looks like there are a couple options for wiring. I have already spliced the Ford fuel pump relay wire (16pin connector) to the tan RF relay wire in the fuse block. It appears the light green gas sender wire is already wired in the rear harness connector and dash harness connector. I think I'll leave that alone for simplicity's sake.

Thanks for your help:cool:

[Jdauble]

Hello Brian,

I’m at the same exact point as this on my Coyote - Roadster build and struggling with the electric harness. I literally am stumped with the same exact sending unit harness questions. I’m good now with the removal of the green radiator and tan choke wires, but confused on the oil temp, oil pressure and water temp connections. Can you tell me how you ended up connecting and how much of the vintage gauge harness vs. RF sending unit harness you used? Dazed and confused. Thanks!



Need some help guys. I'm working on wiring the coyote. Following the Ron Francis instructions and FFR coyote build instructions. I'm at the point where I need to install and connect the Ron Francis sending harness. Its consists of (7) wires:

-Blue (Water temp)
-Light Blue (Oil Temp)-I don't think this one is used on a standard build. I have no sensor in the oil pan.
-Grey (Oil Pressure)
-Black (Ground 1)
-Black (Ground 2)
-Tan (Electric Choke)-Not needed w/ coyote
-Green (Fan Thermo wire)

I also have Vintage Gages and they came with Oil Pressure harness (Blk & White wires) with crimp on ring connectors for the sending unit studs and a Water Temp Harness with connector to sending unit.

Question #1- Since the vintage gages came with harnesses, do I need the Blue, Grey or black ground wires in the RF sending harness??

Question #2-Do I need to do anything with the Green Fan thermo wire if I'm going to let the Ford ECM control the fan via orange ford wire?

If the answers to #1 and #2 are NO...then can I eliminate the entire harness? I must be missing something obvious because I have not found any questions/comments like this.124672

[Mike Garrett]

If you are still working on this I’ll tell you what I did. I too am a little nervous about cutting and splicing into the RF harness so I followed the directions That came with the gauges. I ran both the oil pressure and water temp wires from the gauge kit to the senders which are both at the front of the left side of the engine right below the head. Then I cut off and put on shrink tubes on the stubs of the RF harness and hid them. Don’t forget you will need to use the oil pressure sender with the gauge kit For the gauge and also use the Ford factory sender unit to send the oil pressure reading to the computer. That was a little difficult.

[tbl100]

If you are still working on this I’ll tell you what I did. I too am a little nervous about cutting and splicing into the RF harness so I followed the directions That came with the gauges. I ran both the oil pressure and water temp wires from the gauge kit to the senders which are both at the front of the left side of the engine right below the head. Then I cut off and put on shrink tubes on the stubs of the RF harness and hid them. Don’t forget you will need to use the oil pressure sender with the gauge kit For the gauge and also use the Ford factory sender unit to send the oil pressure reading to the computer. That was a little difficult.

Hi Mike,

I did not use the Ford factory sender unit to send the oil pressure reading to the computer. I left the connector just hanging there. Is it required? How do you hook both up? Makes sense that the computer could use the info. I have a Gen 2 Coyote. Thanks.

Tim

[edwardb]

Hi Mike,

I did not use the Ford factory sender unit to send the oil pressure reading to the computer. I left the connector just hanging there. Is it required? How do you hook both up? Makes sense that the computer could use the info. I have a Gen 2 Coyote. Thanks.

Tim

The Gen 2 Coyote does not need the factory oil pressure sending unit. You can take leave the factory one out, tie off the harness connector, and forget about it. It's only the Gen 3 Coyote that needs both. The previous post that mentioned it was a Gen 3 Coyote build.

[More Than You Think]

Edwardb
Thanks for all you great info on the Gen 3 Coyote.
As you have completed your Coyote Gen 3 installation can you share how you connected your O2 sensors from the headers to the Trany harness on the Gen 3 PCM? The leads on the Trany control harness of the Gen 3 are only about 12 inches a part and will not reach side to side for the sensors located in the headers like they do in the Mustang. I know one cant extend the sensor wiring as that will kill the factory calibrations.

[edwardb]

Edwardb
Thanks for all you great info on the Gen 3 Coyote.
As you have completed your Coyote Gen 3 installation can you share how you connected your O2 sensors from the headers to the Trany harness on the Gen 3 PCM? The leads on the Trany control harness of the Gen 3 are only about 12 inches a part and will not reach side to side for the sensors located in the headers like they do in the Mustang. I know one cant extend the sensor wiring as that will kill the factory calibrations.

You're welcome. Experience is a good teacher. Yeah, I know all the instructions caution against changing the O2 sensor leads. That's nice except neither Ford Performance control pack harness I've used (Gen 2 and Gen 3) have lengths on the O2 leads that were usable. Even worse on the Gen 3. Many successfully use extensions. I personally haven't used them, but many recommend Caspers Electronics. Available directly or from sources like Summit. By all accounts works fine.

What I've done, and it has also worked just fine, is to extend and/or adjust the control pack harness wires as needed. Adjust as needed to put the O2 cable connectors where needed. First take off the convolute and reconfigure the harness as much as possible. Then add or subract wire if needed. It's standard hook-up wire and relatively painless. Use the same gauge and ideally the same colors. Don't mess with the O2 sensor leads themselves. Leave those wires and connectors intact as received. I suspect that might be what they're talking about. But also as a practical manner both the insulation and the wire itself are different than usual and not easy to work with. Ask me how I know that.

[tbl100]

The Gen 2 Coyote does not need the factory oil pressure sending unit. You can take leave the factory one out, tie off the harness connector, and forget about it. It's only the Gen 3 Coyote that needs both. The previous post that mentioned it was a Gen 3 Coyote build.

Thank you!!! Yet again... :-)