93 F-150 Gauges

[uzzo2]

Hi all, I have a 93 F-150 with a 4.9 liter that's having gauge troubles. Specifically the oil pressure and temperature gauges, I have replaced the sensors for both and still the same thing. They both move when you turn the ignition switch from off to on but don't seem to move much at all once the vehicle is running. Was just wondering if anyone else has had this problem and what the fix for it was, thanks in advance.

[mechhound]

The oil pressure guage is just an idiot guage(kind of like an idiot light, when you start the engine the guage will come up to some point in the normal range and won't fluctuate with the actual oil pressure unless you almost totally lose oil pressure then it will drop back to read no oil pressure.) The temperature guage isn't that great either.

[dfordski]

There are no sensors involved. Only sender units. If you replaced the ECT sensor, that has no effect on the gauge reading. If you replaced the oil sender w/ the wrong resistance sender unit it will register low w/ little or no movement whatsoever.

[uzzo2]

Originally Posted by dfordski

There are no sensors involved. Only sender units. If you replaced the ECT sensor, that has no effect on the gauge reading. If you replaced the oil sender w/ the wrong resistance sender unit it will register low w/ little or no movement whatsoever.

You are correct, that's what I meant to say, sender units.

[dfordski]

Originally Posted by uzzo2

You are correct, that's what I meant to say, sender units.

So were talking single wire units, that are showing resistance reading to ground thru the senders. The higher the resistance, the lower the reading. A loose, dirty connection or damaged wire will cause this. also an insulating thread sealer especially Teflon tape. To determine if it is gauge related, connect the sender connect wire directly to ground and the gauge should peg all the way over to it's max reading. IF it does, then there probably is a poor quality ground strap connection to the block (there are multiple ground paths installed at the factory. there are reasons for each of them. If the gauges max out, then that would imply the senders are not compatible to the gauge, but I have seen this procedure "wake a lazy gauge up". The problem of low readings sometimes occurs when the instrument panel has been updated w/ a different unit (like when upgrading to a panel w/ a factory tach, from a unit w/o a tach. Some panels require an oil sender p/u that has a matched resister built into the sender p/u(pick up). But as far as I know, the water temp sender is more universal and standard.

[uzzo2]

Originally Posted by dfordski

So were talking single wire units, that are showing resistance reading to ground thru the senders. The higher the resistance, the lower the reading. A loose, dirty connection or damaged wire will cause this. also an insulating thread sealer especially Teflon tape. To determine if it is gauge related, connect the sender connect wire directly to ground and the gauge should peg all the way over to it's max reading. IF it does, then there probably is a poor quality ground strap connection to the block (there are multiple ground paths installed at the factory. there are reasons for each of them. If the gauges max out, then that would imply the senders are not compatible to the gauge, but I have seen this procedure "wake a lazy gauge up". The problem of low readings sometimes occurs when the instrument panel has been updated w/ a different unit (like when upgrading to a panel w/ a factory tach, from a unit w/o a tach. Some panels require an oil sender p/u that has a matched resister built into the sender p/u(pick up). But as far as I know, the water temp sender is more universal and standard.

The oil sending unit is one wire, but the temp. sender is a 2 wire deal.
http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Sensor-BWD_3461785-P_290_R|GRPSENSAMS_575648028___#

[dfordski]

Originally Posted by uzzo2

The oil sending unit is one wire, but the temp. sender is a 2 wire deal.
http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Sensor-BWD_3461785-P_290_R|GRPSENSAMS_575648028___#

Darnifitdon't! Then Teflon tape away! But your link is an ECT sensor (this goes the the computer, not the gauge). You should be looking for a Coolant Temperature Sending Unit! It screws into the side of the block, in the front, driver's side. Here's a great link I think you'll find informative & interesting: Ford Fuel Injection » Home

[uzzo2]

Originally Posted by dfordski

Darnifitdon't! Then Teflon tape away! But your link is an ECT sensor (this goes the the computer, not the gauge). You should be looking for a Coolant Temperature Sending Unit! It screws into the side of the block, in the front, driver's side. Here's a great link I think you'll find informative & interesting: Ford Fuel Injection » Home

Okay thanks , I just assumed that was the sending unit because it is located on the thermostat housing.