This is at idle by the way. I was driving around 35 mph and it was 35psi couldn't get it to 40 psi. What do you think the problem is. A bad sending unit?? only 126k on jeep. Engine runs great only issues is on a cold start it idles a lil rough but I think thats cuz its due for a tune-up. Also has the infamous long start or takes two tries to start.

 

Most likely a bad sending unit. It's about a $30 part, but it's worth it to replace it. If it's not the unit, then at least you have a brand new one with a good seal on it.... less place for oil to leak out.

I know there's a way to test the resistance, but I don't know what Ohms range to tell you so that wouldn't do you any good.

 

Have you confirmed the actual oil pressure reading with a mechanical gauge? If you don't have one, Harbor Freight sells a pretty nice oil pressure test kit for $25. It's not a bad thing to have in your garage, especially driving a Jeep.

If you'd rather jump right to throwing parts at it, the cheap sending units are about $30 from the auto parts stores, but auto parts store sending units are garbage that frequently crap out again after two or three months. It's not uncommon for them to be defective right out of the box, and then you're right back where you started. I don't know why it's so hard for an aftermarket company to make a decent sender, but in this case it's actually better to spend the $60-$65 on a real Mopar sender from the dealer parts department and be done with it.

 

My third in 3 months just pegged out at 80 this morning. All were bought from the dealer and were under warranty. When it works I believe it's fairly accurate but the OEM ones don't seem to last long.

 

Buy a mechanical gauge for peace of mind. I'd go crazy ever seeing my oil gauge at 10 psi. 95% sure it's the sender unit but hey never hurts to be sure.

 

Haven't checked with mechanical guage yet but will do. Today it seemed to idle with higher pressure this morning it was around 40 psi or so. And driving was much higher then yesterday. It seems that it would be a sending unit. At 10psi wouldn't your hear the engine making bad sounds?

 

Are you sure it's the sender? Senders usually fail low. A pegged sender is usually a sign of a bad ground or a short somewhere. If you have had it peg three times in three months, I suspect you have a wiring issue, not a problem with bad senders.

 

x2 on the mechanical gauge. HF is hit or miss sometimes, but their fuel pressure gauge was accurate within about 1-3 PSI. Good enough for testing the kind of range we're looking for though.

BTW, if you guys type in 56031005AB in Rock Auto's "Part Number Search" tab, you can get a MOPAR sender for 46 bucks (plus shipping, of course). I don't know why they don't list it when you search for the part in the catalog.. I find the tend to do that with a lot of things though.

Agreed.

 

Awesome tip. Thanks for that.

That part is probably in their catalog under another vehicle. Senders are fairly generic in design except for the connector. I'd be surprised to find that our sender is unique to our engine and not used on other Chrysler motors with the same oil pressure range.

 

Agreed. I'll usually check their catalogue first, then if I can't find a MOPAR part, I'll look up the MOPAR p/n and check it in that part number search. I'd say I've had about 50% luck with being able to get the MOPAR stuff that way... if I can't, well then I pay the bigger bucks at the dealer or ebay or whatever.

 

The previously listed Mopar part# is no longer available on Rock Auto. You can still get Mopar 5149064ab which Replaces Part Numbers: 5093908aa, 5149064aa, 56028807ab. Follow other people's advice, Jeeps don't like certain "OEM" aftermarket parts, especially when it comes to sensors. This is one of them.