1994 Ford F-150 oil pressure

Tiny
PORTHOS1
  • MEMBER
  • 1994 FORD F-150
  • V8
  • 2WD
  • AUTOMATIC
  • 12,500 MILES
This vehicle has a oil pressure problem. It starts and runs great. Has good power and everything. I just recently purchased it and noticed after driving awhile that the gauge was hovering around the low mark regardless how my rpm were. I replaced the assending unit and it worked better. WEll then tonight I was drving it and when the engine became normal temp the gauge would drop down at idle. Engine wouldnt stall or even run bad. No knocks that I know of. I rev it and the gauge goes back up. I have read bearing problems, bad shaft in pump or I am fine and need a new gauge. Any thoughts? The truck is spotless so it doesnt seem mistreated.
Tuesday, August 24th, 2010 AT 11:41 PM

6 Replies

Tiny
BUDDYCRAIGG
  • MECHANIC
  • 2,262 POSTS
You need to temporarily connect a mechanical gauge to it so see some hard numbers.

10 psi for every 1000 rpm is a general rule for most engines, but Ford likes to run 0-30 weight oil. So I would depending on your oil it may be about 7psi/1000rpm.
Was this
answer
helpful?
Yes
No
Wednesday, August 25th, 2010 AT 1:42 AM
Tiny
PORTHOS1
  • MEMBER
  • 49 POSTS
Does that mean I need to temp. Change the assending unit to get that reading or rent or buy a mechanical pressure tool and hook it to the existing assending unit?
Was this
answer
helpful?
Yes
No
Wednesday, August 25th, 2010 AT 8:18 AM
Tiny
BUDDYCRAIGG
  • MECHANIC
  • 2,262 POSTS
Yes, you will need to remove the electrical sensor and install the mechanical gauge.

If you dont have a testing gauge, a cheap option is to buy one of those add on kits that you install in the dash (just dont put it in the dash)
they run about 25 bucks at most part stores
Was this
answer
helpful?
Yes
No
Wednesday, August 25th, 2010 AT 12:09 PM
Tiny
PORTHOS1
  • MEMBER
  • 49 POSTS
I just got done installing it. I let it warm up and then stopped to check it while idling. Its about 6. Its between the 0 and 10 mark but a little higher. Am I good. Doesnt have a rpm gauge on it. Runs fine. I going to change the oil tommorow with some heaver weight. 10w-40 or 50? Or I am good.
Was this
answer
helpful?
Yes
No
Wednesday, August 25th, 2010 AT 9:37 PM
Tiny
BUDDYCRAIGG
  • MECHANIC
  • 2,262 POSTS
That is a little low. (But still barely safe)
What does the gauge do when you rev it up?

Try a fresh oil change with 10-40 and see how it responds.
Was this
answer
helpful?
Yes
No
Thursday, August 26th, 2010 AT 12:47 AM
Tiny
PORTHOS1
  • MEMBER
  • 49 POSTS
When I rev it up at idle or driving the pressure rises. Still no engine noises or anything. I will flush the oil and put in a thicker oil.
Was this
answer
helpful?
Yes
No
Thursday, August 26th, 2010 AT 12:52 AM

Please login or register to post a reply.

Related Engine Runs Rough Content

How to Read Codes
VIDEO
How to Read Codes
Instructional repair video
Check Engine Light
GUIDE
Check Engine Light
Why is my check engine or service engine soon turned on? In this guide we talk about what this is associated with this notorious light, what it is used for and what you...
VIEW MORE