The Ford Barn

jacob smith · 04-23-2016, 02:49 PM

On start up the pressure reading in my car is perfect. Idle at about 15 running when hot around 25PSI. I checked with a oil pressure gauge. But some time after the car warms up the oriaganl gauge starts to push to the top at about 50. When I come to a idle drops back to around 20. Any thought of what might be wrong here. Do I need a new sending unit. Thanks for the help

J Witt · 04-23-2016, 08:14 PM

I've noticed that the OP goes up and down to some degree (like the gas gauge) based on the voltage output of the generator. It is a resistive circuit that moves the needle depending on the current through the gauge, which will vary with the voltage.

However, if this behavior just started, then it's either the gauge or the sender. The sender is the easier one to change, I expect. You might take note of the generator output when the readings change and see if they match up.

Mine runs about 50 to 20 psi until the oil is thoroughly warm. (20/40 Rotella T3)

John

JSeery · 04-23-2016, 08:33 PM

Quote:

Originally Posted by J Witt

It is a resistive circuit that moves the needle depending on the current through the gauge, which will vary with the voltage.
John

Sorry, that is not correct, it is not a resistive circuit, it is a pulse circuit. There is a set of points in the sender that open and close. The rate at which this occurs determines the current (and there for heat) in the gauge circuit.

All of the early Ford gauges and senders work on a similar principle.

jacob smith · 04-23-2016, 09:38 PM

Funny thing is I just installed a new genorator and it would make sense because when i let off the gas the amps and oil pressure go down. What should be down to solve the promblem or does that mean I need a new sending unit

Terry,OH · 04-24-2016, 07:05 AM

Have your battery checked to make sure it is still good. Charge it up, then take it to one of the auto parts stores.

JSeery · 04-24-2016, 09:43 AM

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I agree with Terry, there is something not correct with the charging/battery system. I would start with the battery, as suggested. If the generator can not keep a good battery charged than need to look into that. But start with the battery, it's the most likely source of the problem.

Lawson Cox · 04-24-2016, 10:20 AM

When you put a new generator on, did you polarize it ?

jacob smith · 04-24-2016, 01:13 PM

I will check the battery but I am not having a issue charging. Amp meter reads around 10 when driving and a little above 0 when idling. I drove it to a show this morning with the lights on and it wa charging .

Lawson I have not polarized the genorator. How do I do that

04-23-2016, 02:49 PM	#1
jacob smith Senior Member Join Date: Nov 2014 Location: New ringgold pa Posts: 311	Oil pressure 36 ford On start up the pressure reading in my car is perfect. Idle at about 15 running when hot around 25PSI. I checked with a oil pressure gauge. But some time after the car warms up the oriaganl gauge starts to push to the top at about 50. When I come to a idle drops back to around 20. Any thought of what might be wrong here. Do I need a new sending unit. Thanks for the help __________________ Ford

04-23-2016, 08:14 PM	#2
J Witt Senior Member Join Date: Mar 2015 Location: Acworth GA Posts: 534	Re: Oil pressure 36 ford I've noticed that the OP goes up and down to some degree (like the gas gauge) based on the voltage output of the generator. It is a resistive circuit that moves the needle depending on the current through the gauge, which will vary with the voltage. However, if this behavior just started, then it's either the gauge or the sender. The sender is the easier one to change, I expect. You might take note of the generator output when the readings change and see if they match up. Mine runs about 50 to 20 psi until the oil is thoroughly warm. (20/40 Rotella T3) John __________________ Houston, Tranquility base here. The Eagle has landed.

04-23-2016, 09:38 PM	#4
jacob smith Senior Member Join Date: Nov 2014 Location: New ringgold pa Posts: 311	Re: Oil pressure 36 ford Funny thing is I just installed a new genorator and it would make sense because when i let off the gas the amps and oil pressure go down. What should be down to solve the promblem or does that mean I need a new sending unit __________________ Ford

04-24-2016, 07:05 AM	#5
Terry,OH Senior Member Join Date: May 2010 Posts: 4,743	Re: Oil pressure 36 ford Have your battery checked to make sure it is still good. Charge it up, then take it to one of the auto parts stores.

04-24-2016, 09:43 AM	#6
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: Oil pressure 36 ford Sponsored Links (Register now to hide all advertisements) I agree with Terry, there is something not correct with the charging/battery system. I would start with the battery, as suggested. If the generator can not keep a good battery charged than need to look into that. But start with the battery, it's the most likely source of the problem.

04-24-2016, 10:20 AM	#7
Lawson Cox Senior Member Join Date: May 2010 Location: Above the gnat line in Georgia Posts: 7,009	Re: Oil pressure 36 ford When you put a new generator on, did you polarize it ? __________________ Life is like a roll of toilet paper. The closer to the end, the faster it goes. It is better to be seen, than viewed. "We sleep safe in our beds because rough men stand ready in the night to visit violence on those who would do us harm".

04-24-2016, 01:13 PM	#8
jacob smith Senior Member Join Date: Nov 2014 Location: New ringgold pa Posts: 311	Re: Oil pressure 36 ford I will check the battery but I am not having a issue charging. Amp meter reads around 10 when driving and a little above 0 when idling. I drove it to a show this morning with the lights on and it wa charging . Lawson I have not polarized the genorator. How do I do that __________________ Ford