How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Juan Crespo Your Own Question
Juan Crespo
Juan Crespo, ASE Certified Technician
Category: Dodge
Satisfied Customers: 1526
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
Type Your Dodge Question Here...
Juan Crespo is online now
A new question is answered every 9 seconds

Cherokee srt8, oil pressure t 99psi days then 0 psi.

Customer Question

cherokee srt8, oil pressure hit 99psi for two days then 0 psi. Installed new sensor on oil filter adapter and read 64 psi when I crunk her up last night. This morning she wouldn't start, after removing neg cable for a couple minutes, it runs after a lengthy crank duration. Getting several codes now, bought a bosh diagnostic tool and was searching web for any extra info.
JA: Thanks. Can you give me any more details about your issue?
Customer: Oil pressure read 99psi for two days, then went to 0psi. Oil temp stays consistent as does water temp. Just replaced oil pressure sensor, now she is hard to start
JA: OK got it. Last thing — Dodge Mechanics generally expect a deposit of about $18 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 1 year ago.
Category: Dodge
Expert:  Juan Crespo replied 1 year ago.

What is the actual oil pressure as taken with an oil pressure tester?

Customer: replied 1 year ago.
Yet to get that far, bought an oil gauge just to temporarily install to check pressure. Problem now is hard starting and got several codes to go through: P0335, P2122 P0642, C121C and U3FFF. These codes are from use with a Bosh brand diagnostic tool (obd)
Customer: replied 1 year ago.
I didn't disconnect the battery before unplugging and replacing the oil pressure sensor. Bet I should have, lol
Expert:  Juan Crespo replied 1 year ago.

Well, that's the thing; we should first check the basics, then move on to the codes. By the way, beware of cheap code readers when working on these vehicles - for example U3FFF is not a recognized Jeep code, which might mean your code reader cannot correctly interpret network codes.

Customer: replied 1 year ago.
was so sure everything was ok last night once sensor was replaced and once fired up I was getting 64 psi on the dash readout. This morning was a different story when it just cranked over without firing. All the added codes has me all messed up now. Thanx for your help Juan, going to go see about getting the mechanical gauge hooked up to get what I feel is a more accurate oil pressure.
Expert:  Juan Crespo replied 1 year ago.

OK. Let me know when you have those oil pressure readings and we'll take it from there.

Customer: replied 1 year ago.
Ok got mechanical gauge done and she fired up like new, wierd. Gauge has 0, 25, 50, 75, 100 psi readings with a line increments half way between each. Oil pressure reads half way between 50 & 75 psi (67.5psi?). Throttle works fine and all lights on dash are off.
Expert:  Juan Crespo replied 1 year ago.

You need to find a way to connect that gauge inline with the OP sensor so any discrepancies can be shown and the truck can be driven - most OBD-II monitors will only execute after the engine is warm and in Close Loop. So far, all we have is that cold-engine reading of 67.5 psi or so, which really doesn't tell us much.

One more thing, trying to diagnose this truck with just a code reader is like trying to fly to the moon on the Wright brothers airplane ;-)

Customer: replied 1 year ago.
we need operating temperatures with both gauge and sensor hooked up, got it.
Expert:  Juan Crespo replied 1 year ago.

That would be a good starting point. However, going from there without a dealer-level scan tool might not be possible.