[TexTJ]

I have a 2005 TJ and I have to start it twice to get the oil pressure gauge to work. I have changed the sending unit and checked all the grounds. It has to be started twice every time within 30 seconds. It sounds like something electrical but I cant figure it out.

 

[97lon]

Check your oil filter

 

[wushaw]

Screw in a mechanical oil pressure gauge to verify if it is electrical or mechanical.

 

[TexTJ]

It's not a mechanical problem. I can drive it all day and no noises. There are no inconsistency to it at all. After you start it you have to turn it off and restart it within 30 seconds to make the gauge work.

 

[wushaw]

Bad connection between the sending unit & gauge then.

 

[1jbikes11]

go buy a mechanical oil pressure gauge run a T bt the sending unit and new gauge then see if you have pressure if the mechanical says you have pressure then your good, you can get one and all the hardware for under 25 bucks at any auto parts store.If it is isnt reading any pressure then you need to go after your pump.Mechanical oil gauge is more accurate.

 

[TexTJ]

I really don't see it as a bad pump. It is always the same. A mechanical problem will fluctuate some times, this is always the same. When you start it the gauge stays at zero, you turn it off and restart it and it comes back on and jumps to normal. If you have had this exact problem you will know what I'm talking about. It does not loose pressure or fluctuate, it just needs to be started twice to work.

 

[Zeep]

Possibly the buss connection on the back of your cluster?

 

[jkp]

The "oil pressure gauge" in your '05 is nothing more than an idiot light. The "sending unit" is a switch that closes at something like 5 psi. When computer sees the switch close, it moves the needle to mid-scale.

I'd check to see if your oil filter is draining due to a bad anti-drainback valve. I believe it has to be up above min press in 5 secs or it will move the gauge to "L."

You can also run the instrument cluster self-test by holding in the trip odo reset and turning the key to on. You'll see all the gauges run through test and then any faults will be displayed in the odo.

 

[TexTJ]

I have tested the instrument cluster by holding down the trip as it cycles through and no error codes. I have also tried wix, fram and K&N oil filters. The drain back valve you are talking about is it in the filter or the pump?

 

[MidTnSahara]

its in the filter, I would replace the sensor as they are only $45 bucks.

 

[jkp]

Do you get the "Check Gauges" light when the gauge is reading zero?

 

[TexTJ]

I have replaced the sensor and yes the (check gauges) light comes on. I think the computer thinks the sensor is messed up if it does not read within the first few seconds. Is their a way to extend the time it takes to read it.

 

[jkp]

That eliminates the cluster as the problem.

The computer is not seeing any oil pressure initially.

I'd get a mechanical oil pressure gauge to check the oil pressure and see how long it takes to come up. You can probably get one at the auto parts store as a loaner tool.

The time to read is set in the software. Don't know of any way to change it.

 

[TexTJ]

I have even put a 90 elbow and an extension on the sensor thinking that if the sensor was dry or had air trapped in it when it first started was causing it but it changed nothing.

 

[jkp]

How many miles on the engine?

 

[TexTJ]

39,000

 

[jkp]

Really shouldn't be a problem with loose clearances then.

 

[TexTJ]

I don't think so either. I wonder if their is a way to reprogram the computer.

 

[The_Trooper]

The "oil pressure gauge" in your '05 is nothing more than an idiot light. The "sending unit" is a switch that closes at something like 5 psi. When computer sees the switch close, it moves the needle to mid-scale.

I'd check to see if your oil filter is draining due to a bad anti-drainback valve. I believe it has to be up above min press in 5 secs or it will move the gauge to "L."

You can also run the instrument cluster self-test by holding in the trip odo reset and turning the key to on. You'll see all the gauges run through test and then any faults will be displayed in the odo.

Thank you for that post, I didn't know about that little trick.:thumbsup: