When I start my 02 5.4 supercab in the morning, the oil pressure gauge will read normal, then drop to nothing and the idiot light will come on for 2-4 sec. After that it will show proper pressure for a min or so and then drop to nothing again. It only does this in the mornings, after the vehicle is driven for a while, it doesnt do it in the early afternoon after being driven for about 20 mi or so. Is it easy to replace the sending unit? I checked for loose wires under the hood but it looks like a mess there. Any suggestions are appreciated.

lou

 

There's not actually a "sender" - it's just a 6psi switch. The "gauge" is built to show mid-range when the switch closes.

The switch is known to go bad, and it's cheap & easy to replace.

 

Who was it.... Neal? He posted a link or something for a trick to turn the oil gauge into an actual live gauge instead of a glorified idiot light?

If I was to replace the sender, that's what I would do while I was at it.

It went something like....

New sender from some older model that had an actual gauge (I know the stangs did). Some plumbing required to make it fit.

Jumper a resistor behind the instrument panel.

Something to that affect.

You wanna know something weird though? On my 2000 F150 and 2002 Gator, after I change the oil, the idiot gauge will read slightly higher for a couple weeks. It makes absolutely zero sense, but it really does, I s^^t you not! I will have to snap a picture next time and show you guys, it's the damnedest thing!

 

I've posted that several times, but it doesn't apply to '97-up. Your oil gauges have the resistor built in, so it can't be bypassed like on '87-96. You'd have to try to swap the older gauge body onto your gauge face.

BTW
I'm working on doing this to my '99 CV, and although I've swapped the gauge body, I think it rotates the wrong direction for this face. I'll have to scour the JYs for a compatible gauge donor.

 

hey steve83, do you have any ideas where I could research replacing the oil pressure switch on my 5.4? Any pics would be great, on a mechanically inclined scale out of 10 Id say Im a 6 or 7. Got the tools, just not the manual. thanks for the advice.

 

lreyes,
The sending unit should be right next to your oil filter. It has a wire going to it and Steve83 is correct, just an on off switch. The same thing happened to me and then later it would just go dead when it wanted to. It's very concerning when you are going down the road at 70 mph.
Get a new sending unit from Ford (inexpensive) and change it out and your problems will go away.

 

This is on a 4.6L car, but it sounds like a 5.4L truck is VERY similar.



Remember that you can't use the LARGER older true sender because your gauge is specific to the smaller newer switch.

 

thanks guys, bought a switch from advance for about $12 and will install tomorow morning. thanks for all the advice.

 

This if funny, my 2000 F150 just started doing the same thing a week ago. It is very spuratic. The only difference is when it occurs, the oil light and water temp. light both come on. The oil pressure gauge stays at "low". As it warms up the gauge will bounce to normal and fall to "low" and the light turns off and on about three to four times. When the temp reaches "normal" all lights go off and the oil guage stays at normal. I thought it might be the sending unit! Glad I'm not the only one with a trippy 1fitty!

 

There's no way the oil switch alone is affecting the temp light. You have other problems, and I wouldn't wait since it sounds like an electrical/grounding issue that might damage other modules. It might be as simple as a scratch in the film circuit on the back of the cluster, or as bad as an intermittent EEC ground.

 

A new sending unit is less than $10, I think I paid. $9.17 at Ford dealer's Service counter. That's cheaper than an aftermatket unit and it works better. Try replacing that FRN and if you continue to experience probles get your vehicle topwed to a dealer ASAP. If it is the sending unit replacing it will immediately fix the problem.

 

Ahhh man...Steve83 say it ain't so! It doesn't happen all the time, mainly when I don't let the engine warm up. But now that you mention it, the oil pressure and water temp. have nothing to do with each other Off to the stealership for diagnostics

 

the dame thing is still going in with mine after I relaced the switch. After I warm up it doesnt do it anymore. Havnt heard any clanking or oil related noices yet, but after the enigne warms up i no longer have the problem? Sounds like what deejacks got but no water temp light issues...yet.

 

Better get a real guage on that one so you can see what's going on with the pressure. Don't want to blow it up...


Steve

 

lreyes,
If you are still getting low oil pressure when cold and then it goes up when warm than something more is going on. Sounds like a bad oil pump. When things warm up and swell, tolerances get smaller and the pressure is increasing enough to turn off the light. The only way to know for sure is to measure the actual oil pressure using a gauge. You will have to take the readings from cold and during the warm up process. Then you will have to make a decision since replacement of the oil pump is major work.
This is what the oil pump looks like.

On this picture the oil pump is behind the small gears at the bottom where the two chains come together and is driven by the crank.

this is a closer picture with the oil pick-up tube shown on the bottom left.

You may buy some time using higher viscosity oil.
First take the measurements.
Good luck.