The oil pressure gauge on my 1991 Bronco with the 302 engine is really acting weird. It usually runs at about a quarter of the scale no matter what the engine speed. Lately it has started this thing where it will just drop nearly to the bottom of the scale and stay there for maybe five minutes, come back up to one quarter scale, stay there a while, drop again etc, etc. The oil level is fine. I want to check the sending unit but I'll be darned if I can find it. Anybody know where it is? Can I just ground the sending unit wire to test?

Thanks!

 

[font size="1" color="#FF0000"]LAST EDITED ON 08-Apr-01 AT 07:37 AM (EST)[/font]

oil pressure gauge is above the oil filter...check the connector.
i forget how to check it with a test light or vom...maybe someone else knows how.
I believe you can disconnect the connector at the sender and test the sender it for open and closed ckt while engine is running. the results can show if the sender is bad, but......
..the "gauge" is just an on/off set-up..
read this..altho it is for a another engine, it describes the set-up:
"...As you probably know, the factory oil pressure gauge supplied in most of the F-Series pickups during the '90's is just a glorified "idiot light". An oil sensor "switch", not an analog "sender" is plumbed into an oil line and is preset to about 7 psi. This setting is not user-adjustable. When the switch closes, it sends voltage to the oil "pressure" gauge in the cab. To make the gauge read "mid-scale" a dropping resistor of 20 ohms is included in the circuit adjacent to the oil pressure gauge on the printed circuit. If you have a shop manual, the circuit schematic is plainly depicted..."

from:
ford-diesel.com/contents/getitems.php3?Real%20Oil%20Pressure%20Gauge%202

if no one replies soon, have a mech use a mech gauge to check the press and make sure you don't have an oil press problem..!!!
good luck!

 

Thanks for the info AIM. I'll take a look arouind the oil filter for the sending unit. Why in the world would they give you an oil pressure gauge and then put a darn off/on sending unit on it. That is really dumb! I wonder if there is a sending unit available that will make the gauge work as a gauge.....

 

i lost my big reply!....hit the back button and lost it!
ok..here is a site for a stang, but the eng is the same!http://neptune.spacebears.com/cars/stories/oilgauge.html

see the pillar pods?

check summit for one..
click on gauges..then..Gauge Panels, Pods, and Mounting Cups
then...Auto Meter Gauge Pods
ATM-15300 Ford: 1987-96 full size pickup, 2 in., black dual pod ... $24.95
or JC Whitney, autometer, etc.

these pods can be painted with vinyl/plastic type dye/paint to match your interior color..some ford dealers sell them too...Down's Ford in Tom's River, NJ had a sale on them for our model/year(s)..20 dollah...for the dual unit
oh..found another idea!/look!:
http://bbs.off-road.com/wwwthreads//showthreaded.pl?Cat=&Board=offroadfordbroncolate&N umber=149557&page=&view=&sb=&vc=1#Post149557

and this!:
http://bbs.off-road.com/wwwthreads//showthreaded.pl?Cat=&Board=offroadfordbroncolate&N umber=149115&page=&view=&sb=&vc=1#Post149115

.........

ford switched to these on/off's to halt customer complaints (from the mass unwashed..lol) about the fluctuating readings fom the true press gauges...figures!..huh?

the intellitronix www iste is down!
http://www.intellitronix.com/

 

Changed out that little ole sending unit today (about 7 bucks) and I'm happy to report that the oil pressure gauge is at about 3/4 and holding steady! Think I'll just leave well enough alone but thanks for all of the great info! Maybe I can return the favor sometime!

 

i have a 87 bronco 351w had the same problem, just buy a new one and put it on, and if that does'nt fix the problem then have someone check the oil pump and compresion. my guess its the sending unit good luck,

 

great!