P.S. the oil pressure sender is screwed into the block adjacent to the oil filter. All you need for this job is a wrench.
Low oil pressure caused by sludge in oil?
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I think from now on I’ll be referring to my oil pump as an “oil pressure sender.”
Well, it's not wrong.
annihil8ted
Member
Ah today I learned something new! I always thought the sender referred to the oil pump (OPDA) (probably after reading it's a good idea to replace with the Crown version) but we're talking about the sensor/sender that plugs in nearby
Makes me feel a lot better then because I'm hoping this means the oil pump is working as intended and no oil starvation happened
Out of curiosity, why is it referred to as a sender instead of a sensor? Or is this something that Mopar decided/industry standard
Makes me feel a lot better then because I'm hoping this means the oil pump is working as intended and no oil starvation happened
Out of curiosity, why is it referred to as a sender instead of a sensor? Or is this something that Mopar decided/industry standard
You know what, I don't know a factual answer. I just always assumed because it sends a signal, but maybe that's wrong.
Sensor is the more technically correct term but sender is just a device that sends a signal elsewhere which qualifies in this usage. The two words are commonly interchanged.
Just something to clarify, the OPDA is not an oil pump either. That's the more modern version of a distributor, known as a camshaft synchronizer which is part of properly timing the engine. The OPDA has a blade at the bottom (like a large flat blade screwdriver) that inserts into the actual oil pump, which turns the pump. A gear is meshed with the camshaft that drives the blade used to turn the oil pump. To replace the actual oil pump, you would drop the oil pan.
A sensor is something that senses an engine parameter and uses that to provide feedback to the engine computer which the engine computer uses to make adjustments on how it runs the engine. For example, oxygen sensor. Oxygen sensor monitors the air to fuel ratio in the exhaust, and provides that to the computer to help the computer adjust how much fuel it sprays to achieve an ideal ratio.
An oil pressure sender (sometimes also called an oil pressure switch) is called as such because it's operating a gauge and possibly a check engine light, but it's not providing any information that the computer uses to adjust anything. So essentially it is just a sending unit, but it's also a switch because if pressure becomes too low, a check engine light can be illuminated. On some vehicles, that's built into the sender itself (making it a light switch, hence the name), on some others, the computer monitors the info from the sender and chooses to light the light when pressure is below a certain psi.
An oil pressure switch/sender is not a sensor.
Technically it is a sensor because it's not technically a switch despite some parts guides erroneously calling it a switch. The FSM refers to it solely as a sensor, see the below page out of the 2004 FSM, one of many pages referring to it as a sensor. Technically it is 3-wire variable resistor that sends a varying voltage to the PCM to indicate the underlying oil pressure. The oil pressure gauge itself no longer indicate the actual varying oil pressure but nevertheless, the PCM gets the true underlying oil pressure from the sensor. If the PCM determines it's within acceptable limits based on the engine rpm it sends the gauge's indicator to the mid-scale position.
WestCoastDan
TJ Addict
BTW, do not confuse pressure for flow.
Put your thumb over the end of a running garden hose; you now have higher pressure, but it provides zero flow.
Technically, we would be better served if they provided us with an oil flow gauge instead of an oil pressure gauge.
Put your thumb over the end of a running garden hose; you now have higher pressure, but it provides zero flow.
Technically, we would be better served if they provided us with an oil flow gauge instead of an oil pressure gauge.
Good flow doesn't mean anything, that could just indicate something like a bad bearing allowing lots of oil to flow around it without everything else receiving adequate oil. That's why cars and Jeeps monitor the oil pressure but not oil flow.
Technically it can be called either sending unit or sensor in the case of a TJ, though it does not really perform sensor duty like a traditional sensor does. They do call it a sending unit in a few locations. But I see your point that they call it sensor much of the time, which I find odd but it is what it is. I do agree that "switch" is not correct in the case of a TJ, and it looks like the only place they call it that is in that one heading in your screenshot. "oil pressure switch" is not found anywhere in the FSM otherwise, although I'm looking at the 97 FSM currently.
Switch would really be correct in an older application like the carbureted CJs where the oil pressure switch actually lit up the check engine light until oil was flowing, therefore it switched the CEL on the dash accordingly. Not too common after that.
Well I have been a AMC 6 driver since way back in the seventy's.
I can tell you they are nearly indestructible.
1980 AMC Spirit with about 40k on it went to drain the oil cracked the drain plug.
Out drains about 3 quarts of black oil with the consistency of molasses, the owner NEVER changed the oil.
Refilled it with straight 40wt and it went another 20k before it was sold.
It still was running smoked a little bit but started up and drove fine.
I can tell you they are nearly indestructible.
1980 AMC Spirit with about 40k on it went to drain the oil cracked the drain plug.
Out drains about 3 quarts of black oil with the consistency of molasses, the owner NEVER changed the oil.
Refilled it with straight 40wt and it went another 20k before it was sold.
It still was running smoked a little bit but started up and drove fine.
Do you think there might be reasons you haven't thought of why the engineers at the various auto manufacturer in the world never included oil flow gauges in our cars or Jeeps or even give us an example of a single modern car from any country with an oil flow gauge? And why those engineers only gave us oil pressure gauges or at least oil pressure idiot lights? It would cost no more to make an oil flow sender than it does an oil pressure sender. Oil flow gauges are important in many industries but they're not used in vehicles because oil pressure is better information to know in an automotive engine.
Not to mention measuring flow only measures what it is at the location of the oil flow sensor, not what the flow is through all parts of the engine. You could have great flow at some points and not at others. If your oil pressure gauge shows a loss of oil pressure and it's not just an oil pressure sender problem you don't have oil pressure anywhere.
If oil flow gauges were actually more useful in cars as you claimed the engineers would have included them instead of oil pressure gauges. And they're not.
WestCoastDan
TJ Addict
Oil pressure without flow is useless, Jerry.
Providing a flow meter isn’t practical as it would only indicate a single location of flow.
Oil pressure is the de facto indicator because it is easy to measure, but if there are clogged oil lines and/or passages in the engine, it only tells part of the story.
As a point of reference, you could literally pour oil from the jug directly over the valve train and it would be sufficiently lubricated - WITH ZERO OIL PRESSURE.
AGAIN, I stated that one should not confuse the two (pressure vs. flow) as they are not the same.
That is all.
Providing a flow meter isn’t practical as it would only indicate a single location of flow.
Oil pressure is the de facto indicator because it is easy to measure, but if there are clogged oil lines and/or passages in the engine, it only tells part of the story.
As a point of reference, you could literally pour oil from the jug directly over the valve train and it would be sufficiently lubricated - WITH ZERO OIL PRESSURE.
AGAIN, I stated that one should not confuse the two (pressure vs. flow) as they are not the same.
That is all.