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Is my oil pump dead?

  • Thread starter Thread starter cammed89lx
  • Start date Start date Nov 19, 2010
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cammed89lx

New Member
Oct 25, 2010
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Nov 19, 2010
#1
  • Nov 19, 2010
  • #1
Hello all. First off my oil psi gauge almost overnight (2-3 days) went from reading 20 psi while idling when warm to about 7-3 psi when warm. im in PA so its starting to get a little colder out, so im not sure if its the actual pump, the gauge, or anything else, so today i changed the oil, I used 5w 30, in hopes that it would "fix" the problem, but now it idles at a little below 10psi. So im still confused. My car is a freshly rebuilt 306 with only 3000 miles on the motor and tranny, and the car just started reading low oil about 3 weeks ago. However when the psi reads that low the car still sounds fine, no noises or anything, and it still runs and drives nicely so im not sure. other mods are f303 cam, afr165 heads, 1.6rr, KB pistons, 650 carb, airgap intake, im hoping its just the gauge but thought id get everyone elses opinions, thanks guys for the help.
 

2000xp8

SN Certified Technician
Aug 8, 2003
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NJ
Nov 19, 2010
#2
  • Nov 19, 2010
  • #2
What kind of gauge are we talking about?
 
C

cammed89lx

New Member
Oct 25, 2010
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Nov 19, 2010
#3
  • Nov 19, 2010
  • #3
Its an aftermarket sunpro gauge.
 

281pony

Active Member
Aug 31, 2003
2,681
2
46
Oly, WA
Nov 19, 2010
#4
  • Nov 19, 2010
  • #4
20 psi idle? wow that is low imo.

can you try a different gauge? i see 34-40 at hot idle in mine with a stock oil pump after 1 hr + drives.
 

SMOKEDYA

20+ Year Stangneter
Jul 13, 2003
3,637
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Tucson AZ
Nov 19, 2010
#5
  • Nov 19, 2010
  • #5
My engine is a fresh (sorta) rebuild and i have low PSI at idle.I wouldnt sweat it as long as there isnt anything in the oil (debris) and it's not any funny or unsual noise's comming from it. peace







john
 

rd

Founding Member
Jan 12, 2000
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Ocean Springs MS
Nov 19, 2010
#6
  • Nov 19, 2010
  • #6
Check the gage, especially if it is electric, as well as the sender and grounds.

Had a 351 that had 10 or less at idle the day I bought it, and the same 6 years and 50k miles later when I sold it.

Maybe try 10w30 or 10w40. I had one 302 that I redid that the 10w40 would peg the stock gage, but 10w30 works fine.
 
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cammed89lx

New Member
Oct 25, 2010
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Nov 20, 2010
#7
  • Nov 20, 2010
  • #7
Hello everybody and thank you for the responses. I was definately thinking about getting a different gauge, because its starting to freak me out a bit. And no debris in oil, oil looked almost brand new after about 1500 miles of driving, i know thats not many miles but i was expecting debris after my psi started goin down. And i previously had 10w 30 in it and it was lower. so im not sure. I will defintaly check the gauge first then do some more investigation. Thanks again everybody.
 

jrichker

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Nov 20, 2010
#8
  • Nov 20, 2010
  • #8
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 brown/red wire on the radio wiring harness. There are 2 connectors in the radio wiring harness, but only one of them has the light brown/red wire you need for gauge illumination. Solder the gauge lighting wire to the light brown/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.

 
1

1990MustangLX50

Member
Jul 11, 2007
89
0
7
Nov 20, 2010
#9
  • Nov 20, 2010
  • #9
factory spec oil pressure is 40-60psi when hot at 2000 rpms. You should check with a mechinal guage and if it is still low than you may have an issue thats pretty low.
 
C

cammed89lx

New Member
Oct 25, 2010
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Nov 21, 2010
#10
  • Nov 21, 2010
  • #10
yea my car at 2000 rpm in 1st,2nd, and 3rd gear is around 30-40psi, then 4th and 5th gear is at about 20-25 psi.
 
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