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boostedstang
02-02-2004, 10:02 PM
My oil gauge goes back and forward. Like it is ticking. I don't think the oil pressure is really doing this just had it rebuilt. Any ideal why it is doing this. It dose not do it all the time just every now and again. It always goes back to the high side.

smashedheadcat
02-02-2004, 10:34 PM
Think of the factory oil pressure guage as a switch. When the oil pressure reaches a certain psi (I believe like 8-10psi). When that pressure is reached, it completes a ground, and will show about 60% of the guage's full sweep. So it's pretty much either 60% press, or zero. Not trying to scare you, but my factory guage started flickering after my rebuild, and a few seconds later...... It was time for another rebuild. I had an autometer guage as well, so I had a secondary indication. I would check to make sure the wire on the oil pressure switch is on all the way, and if it is....... take it and get a direct pressure reading guage hooked up to it. Monitor the oil pressure. I used a high volume oil pump, and my oil pressure @ idle (when the car is still cold) is around 95psi. After it warms up, it goes down to about 45psi. If it's really hot out, it'll idle around 35psi. If I almost stall the car out, it will go down to about 25psi, but never anything less than that. If you're down to the point where the factory gauge (assuming it's working properly) is giving a low pressure indication, something is seriously wrong.

GeoSnake
02-03-2004, 01:30 PM
The oil pressure sending unit could also need replacing. They are around $12 from Ford. The sending unit is located near the oil filter housing. Replace the sending unit at your next oil change and if it fixes it great, if it doesn't you aren't out that much $.

Levi
02-03-2004, 01:51 PM
Now I am thinking I need a real oil pressure gauge. I wonder what it would take to hook one up?

boostedstang
02-03-2004, 08:20 PM
I know it has a new oil pump. So the oil pressure should be good. It did this before my rebuild. But from what it sound like I need a new sending unit. I am going to get a autometer oil pressure gauges. So I will just keep a eye on it.

steve
02-04-2004, 04:30 AM
Hey Smashedheadcat, my oil pressure guage occasionally flickers between just past midpoint and just before midpoint, is this normal. Most of the time it's just past midpoint. The other day it was between just before midpoint and just after midpoint. I turned the car off for a couple minutes and it returned to it's normal position, which is about 60% full sweep or just past midpoint. The car is a 99 cobra with 35k. Is something wrong with my motor, or is this normal. It's never dropped below 40% full sweep. The car runs great and pulls hard.

Later:eek:

tcrews
02-04-2004, 07:52 AM
The stock oil pressure gauge is an on/off switch only. If you have 4psi of oil pressure it'll read just past the mid-point. At no point should you see if "flicker" between anything other than 0 when off and just past the midpoint when on. If it does move, it's more an indication of a failing oil pressure sending unit than anything else. The guage is really almost completely useless.

I'm doubting anything is wrong with your motor, more likely the oil pressure sending unit.

GeoSnake
02-05-2004, 01:23 PM
Tom and Josh are correct. The stock gauge is just an "idiot" light. That is why I now have an Autometer oil pressure gauge.

smashedheadcat
02-05-2004, 07:01 PM
Originally posted by Levi
Now I am thinking I need a real oil pressure gauge. I wonder what it would take to hook one up?

Hooking up an oil pressure guage is very very easy. I ran mine into the a-pillar. First, just run a single wire from the a-pillar to any 12volt power source. (Mine is to the radio wire) Second, just run a ground to anything your can find. (mine is on the beam behind the instrument cluster) Third wire, just run it through the firewall (mine went through the same hole as the steering shaft. 4th wire, just run it down to the light switch. (this, obviously, will allow the guage to light up when your lights are on, also, give you full dimming control. If you want, you can run it to the back of the air conditioning panel too. It's the white wire. (lights) Finally, remove the factory oil pressure sending unit. It's really small, and it has a black cap with a small post sticking out of it. Take the wire off the post, and unscrew the pressure guage from the block. (mine just barely dripped oil, so you shouldn't have to drain your oil to do this) Then, thread the new sending unit (from autometer) into the block. Trash the old one, or buy a "t" fitting if you still want the factory guage to work. Finally, that wire you ran through the firewall, hook it up to the new sending unit. And that's it. It sounds kinda tough, but it's very simple, and only takes about 1/2 hour to an hour to do, and do right.

Levi
02-05-2004, 07:28 PM
Thanks for the info Josh, this will work out great. :thumbsup:

smashedheadcat
02-05-2004, 08:12 PM
Originally posted by Levi
Thanks for the info Josh, this will work out great. :thumbsup:

No problem. I'm glad to help out when I can. :thumbsup:

Lumpydogs
02-06-2004, 01:14 PM
Holy Cow - Smashedheadcat

Great Instructions. I wasn't even considering this mod but
after reading your post I think I might do it.

"Great Club, Great People"

smashedheadcat
02-06-2004, 03:27 PM
Originally posted by Lumpydogs
Holy Cow - Smashedheadcat

Great Instructions. I wasn't even considering this mod but
after reading your post I think I might do it.

"Great Club, Great People"

It's really easy to do. I snapped a quick pic of the autometer sending unit so you can see where it goes. (its the copper colored thing by the way. The red hose is the oil pressure line for the blower. I know my car is a mess, and that's what it gets for being broken. :D

smashedheadcat
02-06-2004, 03:29 PM
Notice the paper in there. :D I didn't have a block of wood to put between the jack and the oil pan, so a big stack of paper had to do. he he he.... okay, another view.......

smashedheadcat
02-06-2004, 03:30 PM
And the guage.......

Levi
02-06-2004, 03:46 PM
That looks Sweeeeeeeeet.:thumbsup:

smashedheadcat
02-06-2004, 05:41 PM
Here's a better one of the interior.......