Oil Pressure Problem?...

[Benboi92GT]

Problem: At idle, oil pressure would drop to 0 (stock gauge and yes I know they are crap but dont have a mechanical one lying around) and would raise with acceleration. Cold, the oil pressure stays up, when it gets warm is when this starts happening.

Now I've done some research and have gathered the possible problems together. As I understand, it could be a split block causing the pressure to bleed off, bearings could be shot, oil pump could be bad, or it could be the pressure sending unit. Just now I picked up another sending unit from O'Reillys and slapped that on there.

Bam, thought the problem was fixed. Started her up and the needle sat still, for a bit. Now it still drops to zero, but instead of just staying at 0 like it did, it bounces up and down like a kid on crack in a bouncy castle (no I have never witnessed this occurrence but I would assume it would look something like my oil gauge does after the new sending unit, lol). This leads me to assume it had SOMETHING to do with the sending unit? If the old one wasnt bad why would it change how my oil gauge fluctuates. But if it IS a bad sending unit, why didnt it fix the problem?

My next step will be to cut open the oil filter tomorrow. What should I look for? Im going to cut it open with a hacksaw, will I be able to tell the difference from bearing material and casing material? Can a bad oil filter CAUSE my oil pressure to do what it's doing?

Side note: My car runs fine, no noises. If I had no oil pressure, and it has been like this for awhile (I know I'm stupid) wouldn't my engine be toast already? Surely you cant drive a car around with a broken block... It doesnt leak a drop of oil anywhere.

Im praying that it is the oil filter, but I'm never that lucky. Thanks d00ds.

 

[Exile]

Everyone knows that all the fox body mustangs factory instrument gauges are total crap, and a lot of the factory gauges now days dont function properly, if they even still work. A lot of them dont. So besides the speedometer, and maybe gas gauge, I really wouldnt rely on the factory gauges to be all that accurate in a time in need.

So instead of trying to second guess what the problem is (or what its not), buying/changing parts, hacking your oil filter apart, and what not, I would start with buying a good aftermarket oil pressure gauge (which you need), then see how bad your oil pressure fluctuates (or doesnt), and then go from there. (if needed) Might just be your factory oil pressure gauge acting up.

All fox body mustangs should have at least an aftermarket tachometer, temperature gauge, and oil pressure gauge.

 

[Benboi92GT]

Everyone knows that all the fox body mustangs factory instrument gauges are total crap, and a lot of the factory gauges now days dont function properly, if they even still work. A lot of them dont. So besides the speedometer, and maybe gas gauge, I really wouldnt rely on the factory gauges to be all that accurate in a time in need.

So instead of trying to second guess what the problem is (or what its not), buying/changing parts, hacking your oil filter apart, and what not, I would start with buying a good aftermarket oil pressure gauge (which you need), then see how bad your oil pressure fluctuates (or doesnt), and then go from there. (if needed) Might just be your factory oil pressure gauge acting up.

All fox body mustangs should have at least an aftermarket tachometer, temperature gauge, and oil pressure gauge.

If you dont mind me asking, why should they have an aftermarket tachometer?

 

[Exile]

If you dont mind me asking, why should they have an aftermarket tachometer?

The stock tachometers have been known to be off. Even if only off by 1 grand could cause problems.

Lets just say your pushin your motor, and power-shiftin at what you think is 6000-6500 rpm's going by your stock tachometer, but then you find out that your really shifting at 7000-7500 rpm's.

 

[mob]

All the speculation is pointless until you get a new gauge on there. The stock oil pressure gauge is probably the worst gauge our cars have out of all of them. I would just go with an aftermarket electric gauge, its a lot easier to install. Things like low battery voltage or even a surge can cause the gauge to just drop to 0. It used to happen to mine and I began freaking out as well thinking my engine was just gone. Put an autometer electric gauge on it and problem solved.

 

[Benboi92GT]

All the speculation is pointless until you get a new gauge on there. The stock oil pressure gauge is probably the worst gauge our cars have on our car out of all of them. I would just go with an aftermarket electric gauge, its a lot easier to install. Things like low battery voltage or even a surge can cause the gauge to just drop to 0. It used to happen to mine and I began freaking out as well thinking my engine was just gone. Put an autometer electric gauge on it and problem solved.

Cool, so I can use an aftermarket electric gauge? Everything I've read says to use mechanical. Do the electrical just hook right on to the sender like the stock boot?

 

[Exile]

Cool, so I can use an aftermarket electric gauge? Everything I've read says to use mechanical.

You can use electric or mechanical gauges. Its just personal preference. Most people tend to use mechanical gauges like myself.

 

[jrichker]

Here's why smart people choose electrical gauges...

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 blue/red wire on the radio wiring harness. There are 2 connectors in the radio wiring harness, but only one of them has the light blue/red wire you need for gauge illumination. Solder the gauge lighting wire to the light blue/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.

 

[mob]

Cool, so I can use an aftermarket electric gauge? Everything I've read says to use mechanical. Do the electrical just hook right on to the sender like the stock boot?

Yea the mechanical's are more accurate, but you just want to make sure your oil pressure is in the correct range and not at 0. In my opinion a mechanical gauge would be good for seeing if your oil pressure is at 37psi instead of 31psi, get my point? With an electric you can be like eh its around 30 at idle, around 50 under load, and should'nt fluctuate like the stock one does, so you know you have no more worries. And yes the electric gauge wires up just like the factory one, but you will need to use the new sending unit, and wire it to the new gauge. Also there is another wire for a 12v light source to the gauge, but if you try to avoid wiring at all costs its not necessary, just will not be visible in the dark, you can always hook the light up later just get the gauge working.

 

[Benboi92GT]

Thanks for the info guys. News at 10: Changed my oil and cut open old fuel filter, no metal shavings anywhere that I can see. Does this rule out bottom end damage (bearings) for sure? So as I understand, its down to either failing fuel pump or ty factory gauge. (I know, new gauge first, but needed an oil change anyway =P)

P.S. If I just changed oil, and no metal shavings in old filter, what else could cause rocker arm chatter?

 

[jrichker]

The gauge mounted under the hood is the cheap troubleshooting alternative to you problem .The 0-100 PSI gauge cost less than $10 at home improvement centers or hardware stores. Spend another $10-$15 on some good quality hose and fittings and you have a cheap easy solution that you can install in less than an hour.

 

[tca7291]

Do what jrichker said, you won't know for sure until you put a real gauge on it, either under the hood for troubleshooting, or go ahead and install one in your interior permanently. No shavings in the filter is a good sign, but it can't rule out other problems. At the end of everything, you need to put on an after market gauge, or take your chances, you won't know for sure until you put on a reliable gauge.

PS rocker arm chatter can come from many different things, not just running dry. And honestly, if it is running dry it probably isn't rocker arm chatter.