Oil Pressure

35nomoon

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Feb 27, 2017
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Hi new to the forum and having a problem with low oil pressure reading. I replaced the sending unit and installed an aftermarket oil gauge. When I start the engine up my oil pressure reads 40 psi once it warms up it falls to 5-10 psi and when I rev the engine the pressure will not pass 10 psi, oil changed last month is that an indication that the bearing are worn. thanks






93 gt 5spd, Anderson n-21 cam, 1.7rr, 80mm MAF, 373g, long tube hds, trickflow street intake.
 
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G00nies

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Have you checked the oil pressure MECHANICALLY or just been relying on the gauges?
 

jrichker

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Mechanical oil pressure gauge installation..
1.) Remove old pressure sender. It is located down by the oil filter and has 1 wire on a push on screw connector.
2.) Install ¼” pipe tee fitting with a short ¼” nipple on the place where you removed the oil pressure sender.
3.) Install the original oil pressure sender back in one of the tee ports.
4.) Install the gauge line restrictor in the remaining port of the tee.
5.) Connect the flex tubing or hydraulic hose to the gauge restrictor. Be sure to route the tubing or hose away from the exhaust manifolds. Be sure to either use hydraulic hose or oil and heat resistant flex tubing for the pressure line. Do not use copper tubing for the connection to the gauge restrictor or engine. Over a period of time, the vibration will work harden the tubing and cause it to crack and fail.
6.) If the gauge is going to mount under the hood, connect it to the end of the hose or flex tubing. Use some Tie-wraps to secure the gauge and its plumbing to the wiring harness on the driver’s side inner fender.
7.) If the gauge is going to mount in the passenger compartment you get to find a place to run the tubing through the firewall. I suggest that you pick your spot from the inside since that is the area with the most difficult access. Do not run the tubing through the exact same hole as the steering shaft. It will tangle up with the steering shaft and cause major problems.
8.) Install the gauge inside the car in the location of your choosing. Connect the pressure line to the gauge and secure it out of the way of moving parts with Tie-wraps.
9.) Be sure to ground the gauge lighting wire to clean, shiny bare metal. Connect the other wire from the gauge lighting to a light blue/red wire on the radio wiring harness. There are 2 connectors in the radio wiring harness, but only one of them has the light blue/red wire you need for gauge illumination. Solder the gauge lighting wire to the light blue/red wire on the radio harness and cover the soldered joint with heat shrink.

How to solder like a pro - Ford Fuel Injection » How To Solder Like a Pro a must read for any automotive wiring job.

Be sure to use a gauge restrictor fitting in the pressure line going to the gauge. The restrictor will prevent all of the engine's oil supply from ending up on the pavement before you can stop it if the gauge line fails. I had a gauge line rupture, and the restrictor fitting saved my engine from serious damage.

 

jrichker

StangNet's favorite TOOL
SN Certified Technician
Mar 10, 2000
27,401
2,846
234
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Dublin GA
lowendmac.com
Mechanical oil pressure gauge installation.
1.) Remove old pressure sender. It is located down by the oil filter and has 1 wire on a push on screw connector.
2.) Install ¼” pipe tee fitting with a short ¼” nipple on the place where you removed the oil pressure sender.
3.) Install the original oil pressure sender back in one of the tee ports.
4.) Install the gauge line restrictor in the remaining port of the tee.
5.) Connect the flex tubing or hydraulic hose to the gauge restrictor. Be sure to route the tubing or hose away from the exhaust manifolds. Be sure to either use hydraulic hose or oil and heat resistant flex tubing for the pressure line. Do not use copper tubing for the connection to the gauge restrictor or engine. Over a period of time, the vibration will work harden the tubing and cause it to crack and fail.
6.) If the gauge is going to mount under the hood, connect it to the end of the hose or flex tubing. Use some Tie-wraps to secure the gauge and its plumbing to the wiring harness on the driver’s side inner fender.
7.) If the gauge is going to mount in the passenger compartment you get to find a place to run the tubing through the firewall. I suggest that you pick your spot from the inside since that is the area with the most difficult access. Do not run the tubing through the exact same hole as the steering shaft. It will tangle up with the steering shaft and cause major problems.
8.) Install the gauge inside the car in the location of your choosing. Connect the pressure line to the gauge and secure it out of the way of moving parts with Tie-wraps.
9.) Be sure to ground the gauge lighting wire to clean, shiny bare metal. Connect the other wire from the gauge lighting to a light blue/red wire on the radio wiring harness. There are 2 connectors in the radio wiring harness, but only one of them has the light blue/red wire you need for gauge illumination. Solder the gauge lighting wire to the light blue/red wire on the radio harness and cover the soldered joint with heat shrink.

How to solder see
View: http://youtu.be/uaYdCRjDr4A
an excellent how to do it.


Be sure to use a gauge restrictor fitting in the pressure line going to the gauge. The restrictor will prevent all of the engine's oil supply from ending up on the pavement before you can stop it if the gauge line fails. I had a gauge line rupture, and the restrictor fitting saved my engine from serious damage.

49295.gif
 
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Hi new to the forum and having a problem with low oil pressure reading. I replaced the sending unit and installed an aftermarket oil gauge. When I start the engine up my oil pressure reads 40 psi once it warms up it falls to 5-10 psi and when I rev the engine the pressure will not pass 10 psi, oil changed last month is that an indication that the bearing are worn. thanks






93 gt 5spd, Anderson n-21 cam, 1.7rr, 80mm MAF, 373g, long tube hds, trickflow street intake.
On the mechanical gauge you installed-it is showing the 40 psi startup-and then drops down to 5-10 psi?
If so-I'd start by draining the oil and straing it through a shop towel or similar. And look for metallic particles. Id cut the oil filter apart and look for the same thing
 

liljoe07

5 Year Member
Feb 18, 2009
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Even if the bearings were in bad shape. I'd expect some kind of increase when revving the engine. Either way, you are looking at some kind of tear down and inspection.
 

35nomoon

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Feb 27, 2017
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Thanks for the reply everyone but decided to go with a 351w so been looking and hard to come by one in the junkyards here in AZ so more likely will have to a buy a reman
 
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