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Delayed reading oil pressure on warm engine

1K views 11 replies 7 participants last post by  whodey247 
#1 ·
I have a 2001 with the 4.0 and auto transmission. I recently replaced the oil pressure sensor with an Eichman unit from Napa. It was reading low at idle and did not seem to be moving much. The new sender seems to work fine when it is a cold start it goes right up to a bit over 40 psi. Once it is fully warm idling in gear it shows right at 20 psi. All of this seems to be working fine.

However, when I restart the engine after it has been sitting for a while (but still a hot engine), it takes maybe 6-7 seconds for the oil gauge to register. It would not bother me except that it starts beeping and the dash flashes a "Check Gauges" light.

It never lasts more than a couple of seconds before the pressure comes up and the light and beeping go off.

I was about to hook up a t fitting and attach a mechanical pressure gauge to see what the real oil pressure is doing, but thought I would check here to see if anyone has an idea as to what may be causing this.

Thanks in advance for any information and/or suggestions.
 
#3 ·
You need to hook up that mechanical gauge to see exactly what pressure it's making. Do it sooner than later. The longer you run an engine without the proper oil pressure the more damage you can do. Your oil pressure is literally the only thing keeping your engine from grinding to a screeching halt.

What kind of mileage does your engine have? Do you know the service history of this vehicle?
 
#5 · (Edited)
I have a 2001 with the 4.0 and auto transmission. I recently replaced the oil pressure sensor with an Eichman unit from Napa. It was reading low at idle and did not seem to be moving much. The new sender seems to work fine when it is a cold start it goes right up to a bit over 40 psi. Once it is fully warm idling in gear it shows right at 20 psi. All of this seems to be working fine.

However, when I restart the engine after it has been sitting for a while (but still a hot engine), it takes maybe 6-7 seconds for the oil gauge to register. It would not bother me except that it starts beeping and the dash flashes a "Check Gauges" light.

It never lasts more than a couple of seconds before the pressure comes up and the light and beeping go off.

I was about to hook up a t fitting and attach a mechanical pressure gauge to see what the real oil pressure is doing, but thought I would check here to see if anyone has an idea as to what may be causing this.

Thanks in advance for any information and/or suggestions.
Oil Pressure Sensors from auto stores can be bad from the get go. I bought one from Oreily's and had the same problem. I put a mopar one in and no more problems.

2001 Jeep Wrangler ELECTRICAL Chassis electrical Senders Mopar Parts Discounted

You may very well have good oil pressure(which I bet you do) as the TJ ones are dummy gauges and don't give a true pressure
 
#12 ·
Any update? Having same problem as you guys. I got the manual gauge and teed it in with sending unit. I noticed that the instrument gauge would peg to the left when the manual gauge showed about 8-9 psi. This happens when the motor is warm and you come to a stop. Mine has never gone to 0 though. Such a PITA.
 
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