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Discussion Starter · #1 ·
I own a 1997 Wrangler Sport that I've had for about 8 years. Last year I started having trouble with the oil pressure gauge. It would fluctuate constantly as I drove. My mechanic changed the oil pump for me but it didn't fix the problem. Finally after changing the oil sending unit it seemed to stay around 40. This week it has started fluctuating worse than it did before. It's almost down to 0 while I'm driving. It basically just jumps around the whole time. I am not losing any power, not leaking any oil, I just changed my oil, plugs, wires, distributor cap & push button all this week. Do you think the oil sending unit could have gone bad so soon? What other problems could I be looking at?

P.s. My check engine light came on ... I panicked thinking it was bearing going out or something horrible. I had a guy at advanced auto run the code & turns out it was from a misfire (that's why I did the tune up)
 

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First, a Check Engine light is not normally an indication of impending catastrophic engine failure. It is normally just indicating something is wrong with the emissions system, misfires, etc. It's when you get a Check Gauges light that something more serious could be happening like a loss of oil pressure, overheating, etc. that needs attention.

Next, realize that oil pressure is supposed to vary. It is not supposed to remain constant since the oil pump is driven by the engine. Oil pressure varies in direct step with engine RPMs... low pressure at idle RPMs, higher pressure at higher RPMs. The faster the engine revs, the harder the oil pump works & the more oil pressure it produces. A good rule-of-thumb for acceptable oil pressure is around 10 psi for every thousand engine RPMs.

Finally, most of the aftermarket oil pressure senders sold by stores like AutoZone are Chinese-made junk. It took three aftermarket oil pressure senders from AutoZone one Sunday when the dealer's parts department was closed before I finally got one that worked properly for my son's Jeep. Get a new oil pressure sender from the dealer or a WeRMopar.com - OEM Parts For Chrysler, Dodge, Jeep, and Ram Vehicles who sells Mopar parts at a discount.

Good luck with it. :)
 

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Discussion Starter · #3 ·
Jerry,

Thank you for the feedback. I'm always assuming the worse. The oil pressure gauge was reading the same when I was doing 70 on the highway. It just fluctuates from almost 0 to 60 constantly. I think you're right. The sending unit I bought was from Advanced Auto. Maybe I should try ordering it from Quadratec or something like that? Hopefully that's all it is & it'll be a cheap fix. Thanks for all your help!
 

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No, don't order it from Quadratec! They sell the same cheap Chinese senders you'll find in AutoZone or Advanced Auto.

Did you not see the link to the website I already recommended for you above that sells only real Mopar products?
 

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Discussion Starter · #5 ·
Sorry, I did see your link but was unable to open it on my phone. I'll check it out tonight from my home computer. Thanks for making sure I get the best quality parts!
 

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You also need to seriously reconsider your choice in mechanic. These sensors are notorious for failing and it is very unlikely that any mechanical problem could cause the fluctuation symptoms you described. A good mechanic would have tested it with a mechanical guage or started with the sending unit at least. The last thing that should be replaced is the pump.
 

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Discussion Starter · #7 ·
I'm not sure why he went straight for the oil pump without checking out the sending unit? He's a nice guy who I've known for years so I'm sure he must have truly believed that was the problem. But either way, I'm pretty excited about this forum. It's a bunch of people who know everything there is to know about an old jeep! Thanks for the heads up!
 

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It's a known design flaw of the sending unit. With mine I just unplug it and it works fine. Stick with what the guy posted will work better then the shit ones for sure
 
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