Oil Pressure guage

[Loren Smith]

HELP! I've read several posts but I can't seem to come up with an answer/solution....My 2002 Sport Trac's oil "guage" is acting weird. After warming up, it will flicker up and down, bouncing around but ONLY AT IDLE IN GEAR. If i'm sitting at a red light and shift to neutral, the guage pops back to the center position. If i shift to DRIVE, it will bounce up and down, all the time the RPM of the motor nevers changes. As soon as you start to move and rev it up , it pops back to normal. New oil pump, oil PSI switch ....neither helped. Whats going on?

 

[eevox]

Worn out stepper motor in the instrument cluster. They have little plastic gears in them, and they tend to wear out over time. At least that's what it sounds like. If you can solder, or are willing to learn, you can easily do it yourself. You probably need to go ahead and replace them all at this point.

Otherwise, you'll have to send the cluster to someone who can. Depending on who you use, that can mean anywhere from a few days without the truck to a full week.

 

[Mbrooks420]

Why would being in gear or revving the motor change the bad steppers operation?

 

[CDW6212R]

HELP! I've read several posts but I can't seem to come up with an answer/solution....My 2002 Sport Trac's oil "guage" is acting weird. After warming up, it will flicker up and down, bouncing around but ONLY AT IDLE IN GEAR. If i'm sitting at a red light and shift to neutral, the guage pops back to the center position. If i shift to DRIVE, it will bounce up and down, all the time the RPM of the motor nevers changes. As soon as you start to move and rev it up , it pops back to normal. New oil pump, oil PSI switch ....neither helped. Whats going on?

Ditto. I would test the gauge, but it's just designed to show two positions, off and on, very low on the gauge or near the middle of the gauge.

The sensor is an ON/OFF device, it only detects oil pressure above a certain low point, such as 7psi or near that. So the gauge shows no pressure when the engine is off, but once the engine is running, the gauge should always show something. It should stay near the middle, and not drop quickly to the bottom, ever.

What did you mean by posting it has a new oil pump? How many l miles are on the engine, the new sensor, and the new pump? The SOHC 4.0 has critical need for good oil pressure for the valvetrain. Does the engine make any noises, rattle at all when cold or warmed up?

 

[Loren Smith]

Ditto. I would test the gauge, but it's just designed to show two positions, off and on, very low on the gauge or near the middle of the gauge.

The sensor is an ON/OFF device, it only detects oil pressure above a certain low point, such as 7psi or near that. So the gauge shows no pressure when the engine is off, but once the engine is running, the gauge should always show something. It should stay near the middle, and not drop quickly to the bottom, ever.

What did you mean by posting it has a new oil pump? How many l miles are on the engine, the new sensor, and the new pump? The SOHC 4.0 has critical need for good oil pressure for the valvetrain. Does the engine make any noises, rattle at all when cold or warmed up?

I rebuilt this engine recently...all new timing components and a new oil pump. Maybe 500 miles on motor since. Brand new sensor. No noises whatsoever.


LATEST......On a hunch, I removed the brand new oil psi switch and stuck in the old one and PRESTO! No more fluttering of the needle. Got this switch at O'Reilly's. Won't make that mistake again. Happy now.

 

[eevox]

Glad you found your problem.

My instrument cluster thought was because of my experience with them. When the stepper motors start to go, sometimes they can get "floaty" and vague in their indications before they ultimately flatline. At least that's how my speedometer behaved before it flatlined. But a bad sensor is much less of a pain in the ass.

Ever since my dance of crappy cheap alternators with a "lifetime warranty," I'm sticking with Motorcraft parts. I changed out three of those Advanced auto alternators in a little over a year, killing one battery along the way.

 

[Loren Smith]

Glad you found your problem.

My instrument cluster thought was because of my experience with them. When the stepper motors start to go, sometimes they can get "floaty" and vague in their indications before they ultimately flatline. At least that's how my speedometer behaved before it flatlined.

After reading your post, I read several similar experiences online. God, I hope I never have to do that. Will probably swap the whole thing out if it starts acting up.

 

[Mbrooks420]

O’Reilly’s has the same parts as everyone else. It’s not like they made the switch.

 

[CDW6212R]

Ditto, parts choices and sources vary a lot. I'm surprised that the new sensor was defective, that's a type of part which is usually fine to choose from any brand. Most of owning cars and doing all of the work on them, is learning which parts are very important to buy from a certain brand, or the OEM. Most parts can be bought from many places or brands, and they will do fine compared to the most expensive etc.

Things like the SOHC external tensioners should only be OEM units, or the cam synchronizer of a 302 V8, no other brand is worth the money or headache.

I'm glad you got it fixed, and quickly, so you can just drive it and enjoy it.

 

[Loren Smith]

Ditto, parts choices and sources vary a lot. I'm surprised that the new sensor was defective, that's a type of part which is usually fine to choose from any brand. Most of owning cars and doing all of the work on them, is learning which parts are very important to buy from a certain brand, or the OEM. Most parts can be bought from many places or brands, and they will do fine compared to the most expensive etc.

Things like the SOHC external tensioners should only be OEM units, or the cam synchronizer of a 302 V8, no other brand is worth the money or headache.

I'm glad you got it fixed, and quickly, so you can just drive it and enjoy it.

Right on! I agree 100% on the tensioners, etc. Not worth the hassle to save a couple $. Ditto on the oil pump. In my opinion, Big B___s to replace with motor in truck. Gotta go with the OEM stuff. Driving it now...happy again. Take care!

 

[CDW6212R]

I can say how the pump is to install in the truck, I did that in 2006, along with R&Ring the balance shaft unit. The pump wasn't too bad with the upper pan removed. I discovered that the balance shaft was out of time with the timing chains, so I had to remove it and rotate it to line up the dot on the gears. I'm sure there is a procedure to do that with it attached, but with the pan off it was less trouble than to hunt the manual and instructions. I hope to not be doing any of that again, I'd much prefer to yank the 4.0 and install a better engine(and trans).