View Full Version : Vintage Gauges - Oil Pressure sensor wiring
tbl100
05-01-2020, 06:56 PM
Hi,
I'm trying to connect the oil pressure sensor that came with the Vintage gauges. It has three wires and the RF harness only has 2 for it. The 3rd wire is a 5 volt reference. I'm inclined to remove the sensor leg of the harness altogether and just run the oil pressure and water temp cables that came with the vintage gauges from the sensors to the gauges. I don't have an oil temp gauge so those wires are not needed. Would this make sense? What have others done?
Thank you,
Tim
wallace18
05-01-2020, 08:20 PM
I always use the cables that come with the gauges.
edwardb
05-01-2020, 09:34 PM
That's a relatively new change from Speedhut. Previous oil pressure sending units from Speedhut for a number of years (and all that I've installed) are 2-wire resistive style units. Now they've gone to a voltage output style sending unit which needs the third 5-volt reference wire. The Ron Francis harness hasn't caught up with this change. Your simplest solution would be to use the supplied Speedhut cable. It has the proper connectors on each end for the sending unit and the gauge.
tbl100
05-01-2020, 09:44 PM
That's a relatively new change from Speedhut. Previous oil pressure sending units from Speedhut for a number of years (and all that I've installed) are 2-wire resistive style units. Now they've gone to a voltage output style sending unit which needs the third 5-volt reference wire. The Ron Francis harness hasn't caught up with this change. Your simplest solution would be to use the supplied Speedhut cable. It has the proper connectors on each end for the sending unit and the gauge.
Ok, thank you for the confirmation. I'll use the Speedhut supplied cables from the sensors directly to the gauges. This basically eliminates the need for the sensor leg of the RF harness. I can remove that completely.
Thanks again,
Tim
rich grsc
05-02-2020, 07:21 AM
I always use the cables that come with the gauges.
I agree, never have used the anything else.
That's a relatively new change from Speedhut. Previous oil pressure sending units from Speedhut for a number of years (and all that I've installed) are 2-wire resistive style units. Now they've gone to a voltage output style sending unit which needs the third 5-volt reference wire. The Ron Francis harness hasn't caught up with this change. Your simplest solution would be to use the supplied Speedhut cable. It has the proper connectors on each end for the sending unit and the gauge.
I bought gauges from Speedhut 5yrs ago and the gauges where 3 wire units.????
edwardb
05-02-2020, 08:19 AM
I bought gauges from Speedhut 5yrs ago and the gauges where 3 wire units.????
Don't know what to tell you. I've had Speedhut gauges from 7, 5 and 2 years ago. All had 2 wire sending units. Oil temp, oil pressure, water temp, fuel gauge. There are 3-wire connections for the gauge itself, e.g. power, lighting and ground. No changes there that I'm aware of.
As for this thread, the former 2-wire oil pressure sender looked like this one: https://www.speedhut.com/ecommerce/product/603/Resistive-Pressure-Sensor---100-psi,-240-33-Ohms-(Speedhut-Line). Many of us are familiar with it. Has a less than stellar quality history. Sometime in the past year or so, Speedhut switched to this 3-wire version on the Factory Five Vintage gauges (and I'm assuming others) that is voltage versus resistance based: https://www.speedhut.com/ecommerce/product/600/Pressure-Sensor---100-psi-(Revolution-and-Legacy). Beside being much more compact, hopefully it's more reliable. Although more than twice the cost. The current Ron Francis harness doesn't have the three wires for this sensor. The Speedhut cable provided with the gauges has the necessary wires plus the appropriate connectors. So is the easiest installation, even though it would bypass the Ron Francis dash harness connectors.
MyBucketList
01-11-2022, 07:59 PM
Don't know what to tell you. I've had Speedhut gauges from 7, 5 and 2 years ago. All had 2 wire sending units. Oil temp, oil pressure, water temp, fuel gauge. There are 3-wire connections for the gauge itself, e.g. power, lighting and ground. No changes there that I'm aware of.
As for this thread, the former 2-wire oil pressure sender looked like this one: https://www.speedhut.com/ecommerce/product/603/Resistive-Pressure-Sensor---100-psi,-240-33-Ohms-(Speedhut-Line). Many of us are familiar with it. Has a less than stellar quality history. Sometime in the past year or so, Speedhut switched to this 3-wire version on the Factory Five Vintage gauges (and I'm assuming others) that is voltage versus resistance based: https://www.speedhut.com/ecommerce/product/600/Pressure-Sensor---100-psi-(Revolution-and-Legacy). Beside being much more compact, hopefully it's more reliable. Although more than twice the cost. The current Ron Francis harness doesn't have the three wires for this sensor. The Speedhut cable provided with the gauges has the necessary wires plus the appropriate connectors. So is the easiest installation, even though it would bypass the Ron Francis dash harness connectors.
My son and I are this point on build as we speak and were glad to find this thread. Based on what we are reading, our plan is to NOT use the RF connections in favor of the wires provided by Speedhut. No issues there... save two quick (potentially noobie) questions. 1) What is the best course of action with the current RF wires?... cut the ends, insolate and secure but basically leave them in the RF harness assembly? 2) For the Speedhut sending wires, is it best to just route them along the outside of the same harness path and secure them with tape / cable ties? I guess that is technically 3 questions. :) Just looking for advice to keep my routings and under the hood as clean as possible. Thanks in advance.
For any unused wires in the harness, I simply blunt cut the end, fold it over on itself about 1/2 an inch and use a piece of heat shrink to isolate it.
rthomas98
01-11-2022, 10:10 PM
I did the same thing that James did and spliced into the RF harness. See post number 165 on his build page for the wiring. Worked great for me.
https://thefactoryfiveforum.com/showthread.php?35795-JB-in-NOVA-s-MK4-build-GAS-N-touring-pipes/page5
edwardb
01-12-2022, 06:44 AM
My son and I are this point on build as we speak and were glad to find this thread. Based on what we are reading, our plan is to NOT use the RF connections in favor of the wires provided by Speedhut. No issues there... save two quick (potentially noobie) questions. 1) What is the best course of action with the current RF wires?... cut the ends, insolate and secure but basically leave them in the RF harness assembly? 2) For the Speedhut sending wires, is it best to just route them along the outside of the same harness path and secure them with tape / cable ties? I guess that is technically 3 questions. :) Just looking for advice to keep my routings and under the hood as clean as possible. Thanks in advance.
1. Unless you're absolutely positive what the wires are, how they're routed, etc. I'd leave unused RF wires in the harness. Cap the ends as others have mentioned and tie them out of the way. There's plenty of room along with the other wires in the harness. I'd recommend only tie wraps and heat shrink on the ends. Try to minimize use of electrical tape if you can. It doesn't age well.
2. Sure, route the Speedhut wires along with the other wires into the engine compartment. You should be able to organize and get all the sender wires in one bundle through a single hole in the firewall. Again, my recommendation is tie wraps, not tape. Or you could put convolute tubing around like the rest of the RF harness.
MyBucketList
01-12-2022, 06:49 AM
1. Unless you're absolutely positive what the wires are, how they're routed, etc. I'd leave unused RF wires in the harness. Cap the ends as others have mentioned and tie them out of the way. There's plenty of room along with the other wires in the harness. I'd recommend only tie wraps and heat shrink on the ends. Try to minimize use of electrical tape if you can. It doesn't age well.
2. Sure, route the Speedhut wires along with the other wires into the engine compartment. You should be able to organize and get all the sender wires in one bundle through a single hole in the firewall. Again, my recommendation is tie wraps, not tape. Or you could put convolute tubing around like the rest of the RF harness.
Makes sense. Will plan per above. Many thanks.