Oil pressure gauge

[Larry valstad]

Hi, my oil pressure gauge went bonkers! It jumped from high to low so fast and hard it bounced over the little peg on the low side! Now it doesn't move! What should I do? Will it affect anything like fault code? Maybe a aftermarket oil pressure gauge under the dash somewhere? Thanks

 

[SWIGIN]

I think you answered your own question.

Even just throwing an aftermarket gauge on temporarily to see what's going on for sure is needed now so you don't blow it up.

Then remove the gauge cluster and remove the lens and lift the needle over the pin.

 

[koda2000]

For some reason this is a common problem on Explorers/Mountaineers. I've had two that did this. I drilled a small hole in the face of the instrument cluster and used a small dental pick to pull the needle back over the peg. I wasn't about to take the cluster apart for something that would probably happen again (and it has). Is the problem the gauge? Is it the sender/switch? A bad connection? No one has figured it out yet. My guess is the sender/switch. On the SOHC engine I'd be concerned about the oil pickup getting blocked by broken pieces of timing chain guides, but on the V8's, as long as you have adequate oil in the engine you're probably fine. I agree that the best fix would be to replace the OE dummy oil pressure gauge with a real one.

 

[CDW6212R]

The problem is likely from the oil pressure staying very close to the sensor's ON/OFF level/point. So you've had the oil pressure basically hover at that special level that made the sensor change quickly from on to off, to on etc, enough to bounce the gauge needle over the bottom pin.

These later Fords don't have a true pressure sensor any longer, the sensor produces two possible signals, On or Off signals. So the gauge is simply reading one of two levels, either near the left when there is too little pressure, or to the middle/right when there is enough. It's a dummy light but displaying as a gauge, showing pressure off, or on.

The older Explorers have a larger oil pressure sensor, instead of the small one you/we have. You can swap to the older sensor, but I don't recall if the gauge is identical from the 95 models to 98+ units. I'm sure someone here has posted what they did to make it work, but it's been a bunch of years, I forgot.

 

[koda2000]

The problem is likely from the oil pressure staying very close to the sensor's ON/OFF level/point. So you've had the oil pressure basically hover at that special level that made the sensor change quickly from on to off, to on etc, enough to bounce the gauge needle over the bottom pin.

These later Fords don't have a true pressure sensor any longer, the sensor produces two possible signals, On or Off signals. So the gauge is simply reading one of two levels, either near the left when there is too little pressure, or to the middle/right when there is enough. It's a dummy light but displaying as a gauge, showing pressure off, or on.

The older Explorers have a larger oil pressure sensor, instead of the small one you/we have. You can swap to the older sensor, but I don't recall if the gauge is identical from the 95 models to 98+ units. I'm sure someone here has posted what they did to make it work, but it's been a bunch of years, I forgot.

I agree with the possibility that oil pressure below 5 PSI can cause the gauge to bounce, but on the SOHC V6 I know for a fact that broken pieces on timing chain guide can/do easily block the oil pick up. Easy to drop the lower oil pan (less easy on a 4x4) and see what you find. While 5W30 is recommended for the SOHC, you might try an oil change with 10w30 and see if that makes any difference. The only real way to know what's happening is to install an aftermarket oil pressure gauge.

I believe there was a way mentioned on how to turn the stock oil pressure gauge into a real gauge, but in addition to changing the sender you had to add/remove a resistor to the gauge.

 

[CDW6212R]

...

I believe there was a way mentioned on how to turn the stock oil pressure gauge into a real gauge, but in addition to changing the sender you had to add/remove a resistor to the gauge.

That sounds familiar.

 

[Larry valstad]

Thanks for the info! My exp is a 2000 with 4.0 ohv.would that cause cel to come on? Also , Could this be the same situation with the temperature gauge? Thanks,Larry

 

[CDW6212R]

The CEL will come on if the oil pressure signal is seen as low during running. The temperature can generate an engine code(CEL) also. Those should not be related unless there is a serious engine problem which creates no pressure and very high coolant temps.

It sounds like you need to check the CEL code very quickly, and the oil pressure too. Don't run the engine at all really unless you feel comfortable that there is oil pressure. Without pressure the engine should clatter fairly loud immediately and all of the time(it'd be like having a plastic bag over your head(the engine is dying(blowing up) immediately)).

How did it sound the last time you parked it, when it was running and you had all other noises off?

 

[koda2000]

The CEL only comes on for emissions related things that are picked up by the PCM as reported by various sensors. As low oil pressure is not emissions related the CEL would not be turned on, however the "CHECK GAGES" light should come on.

If you start hearing your valve lifters clicking while the gauge indicates low/no oil pressure you have a real problem.

 

[CDW6212R]

Interesting, low oil pressure isn't a check engine item?

 

[koda2000]

Interesting, low oil pressure isn't a check engine item?

I don't believe so. I've never seen the CEL come on when my gauge registered no oil pressure and the only place the PCM could receive any oil pressure related info from is the oil pressure switch. As far as I know almost ALL CEL issues are emissions related.

 

[CDW6212R]

I believe you, it's just another thing of countless things, which doesn't make sense.

 

[1998Exp]

The only thing to which that dummy oil pressure sensor (switch) connects is the gauge. The PCM has no oil pressure input, so no CEL for low oil pressure. To paraphrase Koda, if your engine seizes because of lack of lubrication, it's not an emissions issue.

 

[Larry valstad]

Thanks guys, Everything has gotten so confusing these days! Maybe l will have to make the hotrod my daily driver, Real gauges,no sensors, no computer and alot faster haha!!!

 

[CDW6212R]

Stick a Cleveland in it, that'll wake it up, and everyone else.

 

[GlennW]

Thanks so much for the tip on the pegged gauge, that was it! Replaced the sensor, no change, checked new one, sends. little hole, small wire nail with a bent tip held in vice-grips, and voila, it reads!