97 Dakota 3.9l possible gauge/oil issue.
 

Hey, so I have a 1997 Dakota sport 3.9l v6 178k miles, it's a passed down sort of vehicle, and I've had to for quite a few years. Generally it's been decent, never really any major issues, but one thing started maybe a year and a half ago, I had recently replaced the water pump, and tie rods, was on my way to work on the highway (70mph S-limit) and my oil pressure gauge randomly zero'd out with check gauges light poppin on, but once I slowed down, it went back up, this happened multiple times over a month of so, then just stopped, I had checked oil consistently, never had low oil, noises, etc.





Now a bit more than year later the issue has come back, but differently, generally, I start it, pressure's around 50-60, then lowers at idle, but never below 40, until I start driving, itll lower more and more, usually staying around 20, sometimes 10-15, and will just zero out from that 40+ range, or lower, doesn't matter. Oil level is fine still, I hasn't specifically happened when breaking, accelerating, before, or after hitting operating temp, has just been seemingly random. Also in the first bit I had been having this issue on the highway, i was running conventional oil, I've swapped over to full synthetic, a little over a year since, truck runs much better than before, smoother if that makes sense. Something different compared to the first time having this issue over a year prior, is that I've been trying to be more careful, and not drive it until I can figure this out, but I had to out of nessesatie to work, the first start up, seemed really weak, boggy, and the last time driving it home before this, when I let it sit for two days, it did sound rough, weak start, could hear the lifters, you know, almost like rod knock, but not. Didnt have that noise at all the two days I was forced to drive it.




And last thing, my oil seems to also smell like gas, this has been more of a recent development, and I'm sure I can figure that one out, but I'n case it could relate, figured I should mention.

Sorry for the long post.


Any thoughts on this yall? It's getting up there, but I love this truck, and if there's something I personally could fix, I'd like to.




Thanks

Put a mechanical gauge on it, and see what oil pressure is actually doing. The sending units in these have some rather interesting failure modes....... This looks a lot like one of them. :D

Gas in the oil is caused by running excessively rich, or leaking injectors.... How's your gas mileage been of late?

Sounds very much like you need a new oil pressure sender. They do go bad. If your pressure truly dropped to zero, you'd be hearing noises. Just replace it with a Mopar unit. Looks very easy to change, BTW. It sits near your distributor cap. Disconnect the cable, unscrew the unit, screw in the new unit and tighten to snug, reconnect cable.... done.

https://cimg2.ibsrv.net/gimg/dodgefo...1032a631fa.jpg


https://cimg1.ibsrv.net/gimg/dodgefo...12d25d3e71.jpg

Hmmm, it seems decent I suppose, but I've noticed, and this might just be me, if I fill up, always a bit under fill for personal preference, mileage seems fine, maybe even... not good, but decent, around halfish tank, it seems to drop quick, so worse, then towards quarter and below, it seems once again to pick back up, lasting forever, nearly twice the distance from a bit above half, to a quarter. So I'm not 100% I've had times where I went through gas like snow in a furnace, but others where I haven't needed to gas back up for up to three weeks. At the current moment it feels like it more towards to snow/furnace point. Thankfully the injectors, etc, should be decently easy, haven't messed with that stuff personally but I can learn.

As for the replacing, that process seems sooooo easy, bout up there with the tie rods

The gas gauge isn't linear. :) On my 2500, after a fill up, I can go around 60 miles before the gauge even moves off Full. Then, it drops pretty steadily to around half a tank, from there, it drops like a stone to an eighth, and the low fuel light comes on, but, there is STILL 8 gallons of gas in the tank... (34 gallon tank.)