Oil pressure

[jackwalton]

Originally Posted by Pappajohn

if there was an oil pressure sender, even a simple 'pressure/no pressure' version, then surely the dash warning would remain lit until the engine was started and oil pressure attained.

as it is, the light comes on, with ign on, then goes out before engine start-up which points to a level switch with pre-start 'lamp test' function.

Never thought about it as described above, but your spot on.

Oil Warning Light should stay on until engine started and pressure is built up.
Could be programmed out of ECM and not armed until engine starts but that wouldn't really make any sense.
Wonder what the Hemi does Ray. Does Oil Warning light stay on after initial lamp test until engine starts and pressure established ?
As said above on the diesel, Oil Lamp is out before engine turns over.

By the way: The fixed reading on the diesel EVIC of 115 is actually "Kpa" not PSI . This converts to about 16.5 PSI

Jack

[badgx]

Isn't the oil level sensor inside the sump (maybe not) & oil pressure sensor maybe screwed somewhere near to the oil filter housing but you say there isn't a pressure sensor in the crud ???

Here a few useful links to oil pressure sensor for Hemi, as you say its 3 pin & hooked into the PCM

MY CHRYSLER 300C HEMI CAME UP WITH A CODE P0520 ENGINE OIL - JustAnswer

http://www.lxforums.com/board/f88/ho...sensor-200062/

[UK CHRYSLER 300C]

16 psi seems a bit low to me for oil pressure as mine went to 60 psi on start up and I will have a look at my oil light on ign on next time I start the beast,somehow we'll get to the bottom of this quandary between us

[jackwalton]

Yes I agree 16 PSI normally would be too low if it was a proper oil pressure reading, but this is a fiddled reading so the ECM must be fiddled as well to accept 16 PSI as acceptable.

Jack

[devilmaycare]

Assuming an oil pressure measurement were to be made available, what use would it be? If a higher or lower than "normal" pressure was observed, what course of action, if any, would be taken? Would you start stripping the engine down, looking for blockages in the oilways, worn bearings or a faulty pump? Or maybe just replace the sensor? Years ago, I sometimes had the oil warning light refuse to extinguish on tickover on various cars that I owned and in every case the problem was cured by replacing the pressure switch. I've never owned a car that had an oil pressure gauge and can't say I ever missed one. Maybe Chrysler deemed a pressure measurement to be unnecessary and would save a few$ (as per the water-in-fuel detector in the fuel filter).

[jackwalton]

In my opinion an Oil Pressure reading is essential.
I must admit though, on most occassions instrumentation is not believed unless an abnormal or warning signal is accompanied by some other symptoms that confirm the instrumentation is true. i.e. if low pressure reading is accompanied by an engine that starts to sound noisy or feels sluggish.

If it was a slowly falling oil pressure over a few weeks (It should be a reading that should be routinley checked while driving every now and again), the first logical step would be to fix a temporary pressure gauge up to see if the reading was true or false. Not practical at the side of the road I know, but if I had a low oil pressure associated with an unusually rattley engine, I would shut it down straght away and wouldn't run it).

If the low reading is true would be an oil flush and oil and filter change for me.
If pressure reading didn't return to normal, oil pump and relief valve.
After that were into crankshaft main and big end bearings and camshaft problems.

But the idea is to fix the low oil pressure problem before it costs a fortune to fix a seriously damaged engine.
If the oil pressure was monitored I am sure there are quite a few alarm settings in the ECM that would flag up a problem that would warrant a temporary pressure check at the very least. i.e. If you get an alternator charging fault light up the first thing you do is check the alternator output.
Again if they decide its necessary to warn of a failure to charge the battery why cant they provide a pressure guage to protect a £3000 ???? engine.


Jack