Strange wire/line by oil filter. Oil Pressure Regulator Valve Removed?
Strange wire/line by oil filter. Oil Pressure Regulator Valve Removed?
Edit: Title should say "Oil Pressure Sending Unit"
About a year ago, I purchased this car (my 5th FC), and I have been slowly working on it in an attempt to bring it back to a closer-to-factory spec and so that I can make my own modifications. Over the weekend, I noticed these two things in the engine bay by the oil filter:
1. A wire that went nowhere, but was spliced into another wire; and
2. A fitting on the engine that lead into the interior of the vehicle to a cheap, off-brand aftermarket oil gauge.
I would like to remove the aftermarket oil pressure gauge and return the vehicle back to its factory setup.
I was looking through my Hayne's manual and I have the following questions for you 2nd gen gurus:
As it pertains to #1, what is this wire for and where is this wire supposed to go?
As it pertains to #2, what, if anything, belongs where this fitting is? Is it just an access hole from the factory for some sort of dealer/mechanic testing, or did this used to be the oil pressure sending unit fitting? From the pictures, does it look like I even have an oil pressure sending unit anymore? Can I just remove the fitting, the line, and the gauge, and block this hole off? Did my previous owner remove the oil pressure sending unit, send a dummy wire back to the ECU, and then run his own oil pressure gauge in its place?
It should be noted that the oil MOP pump was removed by the previous owner. Are these components related to that removal?
It should also be noted that my low coolant/low oil buzzer is constantly going off. I am not sure if that has something to do with that wire.
Thank you in advance.
About a year ago, I purchased this car (my 5th FC), and I have been slowly working on it in an attempt to bring it back to a closer-to-factory spec and so that I can make my own modifications. Over the weekend, I noticed these two things in the engine bay by the oil filter:
1. A wire that went nowhere, but was spliced into another wire; and
2. A fitting on the engine that lead into the interior of the vehicle to a cheap, off-brand aftermarket oil gauge.
I would like to remove the aftermarket oil pressure gauge and return the vehicle back to its factory setup.
I was looking through my Hayne's manual and I have the following questions for you 2nd gen gurus:
As it pertains to #1, what is this wire for and where is this wire supposed to go?
As it pertains to #2, what, if anything, belongs where this fitting is? Is it just an access hole from the factory for some sort of dealer/mechanic testing, or did this used to be the oil pressure sending unit fitting? From the pictures, does it look like I even have an oil pressure sending unit anymore? Can I just remove the fitting, the line, and the gauge, and block this hole off? Did my previous owner remove the oil pressure sending unit, send a dummy wire back to the ECU, and then run his own oil pressure gauge in its place?
It should be noted that the oil MOP pump was removed by the previous owner. Are these components related to that removal?
It should also be noted that my low coolant/low oil buzzer is constantly going off. I am not sure if that has something to do with that wire.
Thank you in advance.
Last edited by FRFC3S; Mar 28, 2016 at 10:07 AM.
As you can see, this black wire comes off of the engine and goes nowhere, but this yellow wire has been spliced back into it.
I have yet to determine where the black wire comes from or where the yellow wire goes. Obviously that knowledge would help, but I am not at my car, so I was hoping that somebody else could weigh in.
I have yet to determine where the black wire comes from or where the yellow wire goes. Obviously that knowledge would help, but I am not at my car, so I was hoping that somebody else could weigh in.
The Y/R wire in the first pic is the stock oil pressure gauge connection.
Your stock sending unit has been removed and a sending unit compatable with the aftermarket gauge has been put in its place.
There is no external oil pressure regulator on the FC engine.
There is a thermostat in the cooler and pressure relief valves in the oilpan and the filter, but nothing to regulate pressure anywhere else.
The MOP is a separate/standalone system (other than drawing oil from the common reservoir) and has nothing to do with the gauge/warning part of the harness.
I can't tell what you're trying to show in pics 2 and 3 but it looks like you just have a relatively common gauge replacement situation.
To return to stock just replace the sending unit with the Mazda unit and connect the Y/R wire.
In theory.
The low coolant warning is also distinct from any other circuit and has nothing to do with the oil gauge issue.
Edit:
The stock gauge circuit includes a branch that goes to a condenser that is originally bolted to the bellhousing.
It's a black wire terminated in a sugarcube sized black box with a mounting bracket and acts as a buffer for the gauge.
This condenser is often found dangling loose or bolted somewhere else and the gauge works fine without it...as long as the black lead wire isn't grounded. Directly grounding this black or the Y/R wire is bad for the gauge.
Your stock sending unit has been removed and a sending unit compatable with the aftermarket gauge has been put in its place.
There is no external oil pressure regulator on the FC engine.
There is a thermostat in the cooler and pressure relief valves in the oilpan and the filter, but nothing to regulate pressure anywhere else.
The MOP is a separate/standalone system (other than drawing oil from the common reservoir) and has nothing to do with the gauge/warning part of the harness.
I can't tell what you're trying to show in pics 2 and 3 but it looks like you just have a relatively common gauge replacement situation.
To return to stock just replace the sending unit with the Mazda unit and connect the Y/R wire.
In theory.
The low coolant warning is also distinct from any other circuit and has nothing to do with the oil gauge issue.
Edit:
The stock gauge circuit includes a branch that goes to a condenser that is originally bolted to the bellhousing.
It's a black wire terminated in a sugarcube sized black box with a mounting bracket and acts as a buffer for the gauge.
This condenser is often found dangling loose or bolted somewhere else and the gauge works fine without it...as long as the black lead wire isn't grounded. Directly grounding this black or the Y/R wire is bad for the gauge.
Last edited by clokker; Mar 28, 2016 at 10:39 AM.
clokker, thank you. Pics 2 & 3 were for reference.
I guess I need to see if my oil pressure reading still works on my gauge cluster (with the MPH, RPMs, etc.), despite my car not having an OEM oil pressure sending unit.
What is the point of the yellow/red-stripe wire if I no longer have an OEM sending unit? Does it go back to the ECU?
I will attempt to locate the condenser, which I now fear is just chilling somewhere in my transmission tunnel. After some research, it looks like the condenser does very little other than act as a "fuse" to prevent damage to the oem oil pressure gauge.
I guess I need to see if my oil pressure reading still works on my gauge cluster (with the MPH, RPMs, etc.), despite my car not having an OEM oil pressure sending unit.
What is the point of the yellow/red-stripe wire if I no longer have an OEM sending unit? Does it go back to the ECU?
I will attempt to locate the condenser, which I now fear is just chilling somewhere in my transmission tunnel. After some research, it looks like the condenser does very little other than act as a "fuse" to prevent damage to the oem oil pressure gauge.
The Y/R wire in the first pic is the stock oil pressure gauge connection.
Your stock sending unit has been removed and a sending unit compatable with the aftermarket gauge has been put in its place.
There is no external oil pressure regulator on the FC engine.
There is a thermostat in the cooler and pressure relief valves in the oilpan and the filter, but nothing to regulate pressure anywhere else.
The MOP is a separate/standalone system (other than drawing oil from the common reservoir) and has nothing to do with the gauge/warning part of the harness.
I can't tell what you're trying to show in pics 2 and 3 but it looks like you just have a relatively common gauge replacement situation.
To return to stock just replace the sending unit with the Mazda unit and connect the Y/R wire.
In theory.
The low coolant warning is also distinct from any other circuit and has nothing to do with the oil gauge issue.
Edit:
The stock gauge circuit includes a branch that goes to a condenser that is originally bolted to the bellhousing.
It's a black wire terminated in a sugarcube sized black box with a mounting bracket and acts as a buffer for the gauge.
This condenser is often found dangling loose or bolted somewhere else and the gauge works fine without it...as long as the black lead wire isn't grounded. Directly grounding this black or the Y/R wire is bad for the gauge.
Your stock sending unit has been removed and a sending unit compatable with the aftermarket gauge has been put in its place.
There is no external oil pressure regulator on the FC engine.
There is a thermostat in the cooler and pressure relief valves in the oilpan and the filter, but nothing to regulate pressure anywhere else.
The MOP is a separate/standalone system (other than drawing oil from the common reservoir) and has nothing to do with the gauge/warning part of the harness.
I can't tell what you're trying to show in pics 2 and 3 but it looks like you just have a relatively common gauge replacement situation.
To return to stock just replace the sending unit with the Mazda unit and connect the Y/R wire.
In theory.
The low coolant warning is also distinct from any other circuit and has nothing to do with the oil gauge issue.
Edit:
The stock gauge circuit includes a branch that goes to a condenser that is originally bolted to the bellhousing.
It's a black wire terminated in a sugarcube sized black box with a mounting bracket and acts as a buffer for the gauge.
This condenser is often found dangling loose or bolted somewhere else and the gauge works fine without it...as long as the black lead wire isn't grounded. Directly grounding this black or the Y/R wire is bad for the gauge.
Joined: Sep 2005
Posts: 25,581
Likes: 136
From: Smiths Falls.(near Ottawa!.Mapquest IT!)
since you have the yellow/red stripe wire it IS Relevant if you want to put the car back to stock.
It goes to the Gauge..nothing to do with the ECU..Zilch..not applicable!
If someone cut it off and you wanted to do this it wouldn't be so easy as to just putting a oil pressure sensor back on..would it?
The condenser just smooths out the signal to the gauge from the sender.
Some guys have gotten away with running it so you may want to try just tossing a oil pressure sender on and seeing if it works.(That is IF the circuit is not been tampered with more that you know).
It goes to the Gauge..nothing to do with the ECU..Zilch..not applicable!
If someone cut it off and you wanted to do this it wouldn't be so easy as to just putting a oil pressure sensor back on..would it?
The condenser just smooths out the signal to the gauge from the sender.
Some guys have gotten away with running it so you may want to try just tossing a oil pressure sender on and seeing if it works.(That is IF the circuit is not been tampered with more that you know).
It sounds like my previous owner just hacked off the OEM pressure sender and left the wiring hanging there, yet kept the condenser. Splendid. Thanks for the heads up, misterstyx69. It looks like I should be able to return to the stock setup fairly easily.
since you have the yellow/red stripe wire it IS Relevant if you want to put the car back to stock.
It goes to the Gauge..nothing to do with the ECU..Zilch..not applicable!
If someone cut it off and you wanted to do this it wouldn't be so easy as to just putting a oil pressure sensor back on..would it?
The condenser just smooths out the signal to the gauge from the sender.
Some guys have gotten away with running it so you may want to try just tossing a oil pressure sender on and seeing if it works.(That is IF the circuit is not been tampered with more that you know).
It goes to the Gauge..nothing to do with the ECU..Zilch..not applicable!
If someone cut it off and you wanted to do this it wouldn't be so easy as to just putting a oil pressure sensor back on..would it?
The condenser just smooths out the signal to the gauge from the sender.
Some guys have gotten away with running it so you may want to try just tossing a oil pressure sender on and seeing if it works.(That is IF the circuit is not been tampered with more that you know).
Last edited by FRFC3S; Mar 28, 2016 at 12:04 PM.
Assuming an intact harness between the Y/R in the bay and the gauge cluster, your final hurdle- after sending unit install- will be the connector.
The OEM sending unit has a harebrained connector (commonly referred as a "mushroom" by the gastronomically challenged) that is not commonly available.
Fortunately, a standard 1/4" female spade connector can be tweaked to work.
The OEM sending unit has a harebrained connector (commonly referred as a "mushroom" by the gastronomically challenged) that is not commonly available.
Fortunately, a standard 1/4" female spade connector can be tweaked to work.
Thread
Thread Starter
Forum
Replies
Last Post
WyomingTII
2nd Generation Specific (1986-1992)
4
Feb 23, 2016 06:14 PM