oil pressure question

[rurouni20xx]

was out at my fiances shed where my old 3.0 ranger is parked, per the oil sending unit i have little to no oil pressure and the last real drive i was on i lost a few cylinders. this is my question, every time i drove or warmed it up to keep the fuel going in the system i run on all cylinders and idle low but smooth, revs fine etc, almost like nothings wrong w/ it. i dug thru my good ole haynes manual and couldnt find a thing about manually testing the oil pressure, anybody out there know how to hook up a manual mechanical gage and have a spec on what it should be at idle? the trk is 16 yrs old and ive had wiring problems in the past, wouldnt surprise me if my gage or sending unit is gone, just want to double check everything (like i prob should have done to begin w/ but took her out of service herring on the side of caution b4 catastrophe strikes) b4 parking her completely. thanks for any and all replies.

 

[doorgunner]

if ur hearing clattering or rattling from the engine at any rpm--don't run it.
check the H. manual for a (spare) threaded oil pressure passage on the side of the engine & connect a cheapie oil pressure gage to it. Run the tubing to the dash & connect the gage there temporarily.
Now you'll know exactly what oil pressure the pump's putting out (if the pump's working!)

you can also ground the oil pressure wire at the sending unit & the dash gage should peg out (proves the dash gage and wiring is working.

finally...wait for replies from real mechanics

 

[Rearanger]

I'm pretty sure you'll have to remove the gauge fitting at the engine and install a mechanical gauge there. Alternately you could install a "T" fitting at the gauge engine fitting and tap in a mechanical gauge. Don't guess with oil pressure, the cost is just too high.

 

[rurouni20xx]

hence the reason im asking others. when it was running on half the motor it wasnt clanking or clammering just loping and stumbling real bad and the gage read almost nothing. went from "r" on normal to below "n" and started running like shit shortly afterward. i cranked it the other day, ive cranked it one other time and ran/idled/revved fine both times, just the gage reading below "n" and im too leery to drive it. between the oil pressure, the throttle hanging up beyond 60 percent and for almost a yr the check engine light staying on after 30 miles (was told the lights just stay on sometimes and dont worry about it against my better judgement hence the reason i never looked into it) i have a few probs out of her but shes been a hell of a ride the whole time ive had it.

 

[Hawk1339]

If you have already made the idiot gauge mod, disregard.

Otherwise, if you have the stock pressure sensor, then it is merely a pressure switch. It closes at about 8 PSI and a resistor in the cluster makes the gauge read half scale. Under normal conditions, the gauge will read only 0 or half scale.

If it is reading something else, then either the gauge is bad or there is a high resistance somewhere in the sensor circuit.

 

[GMWIGGS]

I installed a T fitting to connect a mechanical pressure guage and keep the pressure switch as well. Definately do not run it until you are sure you have oil pressure. It don't take long to do some serious internal damage without adequate oil pressure. Just get a cheapo guage and see what you got. Oil pressure spec is supposed to be 40 - 60 psi at 2500 rpms with engine at operating temperature. Mine Just barely gets to 45 psi at operating temp and thats with 10w40 oil. Cold oil pressure is just past 60 psi at idle! So theres a sizeable difference between hot and cold oil pressure.

Good luck with your truck!