2.3L ('83-'97) '94 2.3 Oil Pressure Sending Unit

[ForgedCrank]

Maybe?
Ok, I was on a highway drive a couple weeks ago and noticed my oil pressure was dropping... almost to the bottom of the "normal" range on the gauge. Normally when I'm at highway speeds, it reads just under the exact center, just slightly lower. But it wasn't just dropping, it was going up and down. Not a jittery movement, just surging up and down from it's normal level to scary level. No engine noise so I'm 99.9% sure it's not really an oil pressure issue.
I pulled the cluster out of the dash and re-cleaned all of the contacts with alcohol and then deoxit cleaner. Everything seems to be clean and making good contact, but I'm going strictly off visual inspection. At this point I'm guessing maybe it's the sending unit on the head but I dunno.
Do you guys know how to measure the signal coming off of it? Is there a normal resistance range or something when it's powered off and when it's idling or something like that? Or do you think I'm going down the wrong road here? The only thing I can really find as common is a bad ground on the instrument cluster (everything else is working fine), or a faulty sending unit. I'm also reading that people are having all kinds of problems with the aftermarket replacements from the main auto suppliers.
Anyway, do you think the sending unit is the probably culprit? If so, do you guys know of one brand or the other that is actually reliable?
Would love any suggestions, especially ways to test and troubleshoot this proper.

 

[Brain75]

being a '94, unless you replaced it or some PO did, it is an "idiot light" not a gauge... google around "centered needle" - Ford did that, who knows why. The sending unit is basically a switch, less than 5 psi off more than 5psi on... so most likely gauge ground or some other connection in the cluster, but could be a bad gauge I suppose... There is a tech article here on adding a resistor to the back of the cluster and switching to a real sending unit to turn it back into a real gauge.

 

[scotts90ranger]

Yeah, that... the switch on the engine could be bad too

 

[ForgedCrank]

being a '94, unless you replaced it or some PO did, it is an "idiot light" not a gauge... google around "centered needle" - Ford did that, who knows why. The sending unit is basically a switch, less than 5 psi off more than 5psi on... so most likely gauge ground or some other connection in the cluster, but could be a bad gauge I suppose... There is a tech article here on adding a resistor to the back of the cluster and switching to a real sending unit to turn it back into a real gauge.

Ok, this right here is the answer I didn't know I wanted. I'm going to try finding that post... I didn't realize I was being duped by a gauge. I mean, they've never been super accurate, but I hoped to at least get a rough idea from the cluster gauge.

 

[Brain75]

Variable Oil Pressure Gauge Modification - The Ranger Station

Original Poster: Larry Bolan (ratdude747) Difficulty: 6 out of 10 (depending on soldering ability) Time to install: 1-2.5 hours Disclaimer: The Ranger Station.com, The Ranger Station.com Staff, nor the original poster are responsible for you doing this modification to your vehicle. By doing …...

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