Good idea Tom, here is what I found.
I'm going to try the pressure sensor first. If I get the same results I'll work up the guts to rip into the instrument cluster.
In #1 below it sounds like he added a T fitting to keep the original pressure switch and add the new pressure transducer. From the original switch he hooked up a piezo which will sound should the original switch indicate low pressure. Not a bad idea..
Sorry in advance for the long post.
Best regards.
hg
#1------------------------------------------
A few weeks ago there was a thread regarding the bogus oil
> gauge. It was mentioned that by adding a proper sender and
> removing a 20 ohm resistor it could be converted to a correctly
> reading gauge.
This is in the Bryan Richardson's FAQ but here's the info:
3.2. The oil gauge lie
The oil gauge on the Explorer isn't. Simply put, the indicator on the dash looks like a gauge, but it is really only a binary indication as to whether the pressure sensor believes that the engine has sufficient oil pressure or not. If it thinks there is sufficient pressure, then the gauge reads in the "Normal" zone, usually pointing to a single place (without varying based on temperature, RPMs, etc.). If there is not sufficient pressure, then the gauge reads "low." The first item below describes how to convert the "indicator" back into a gauge. Discussion on this topic follows:
Subject: Did the oil pressure modification today; it WORKS!
From: mikey@slic.cts.com (Mike Shirley)
Organization: Muth Valley Ford Oil Pressure Check Station and Bakery
I used an "AutoTune" PT3077B transducer, $15, purchased from Kragen Auto Parts Store. It appears to be a generic application
transducer. Ford's is: Ford sender E4ZZ 9278A, $20.
I went ahead and installed the transducer today. It was a universal 1/4 pipe threaded sender with the "slip over threaded rod" style of electrical connection to the top. Plenty of room for the tee, original switch, and the new transducer. I removed the switch from the 45 degree long- shafted adapter. Used the end of the tee (not the center port) to the adapter, mounted the transducer upward and the switch outward (center port of tee). Was able to plug the original connector into the new transducer. I added a wire for the switch and ran it through the firewall and attached it to a small piezo chime via 12V+ from the switched ignition.
The gauge read just left of the N in Normal prior to disabling the 20 ohm resistor on the dash cluster. After shorting out the resistor, the gauge needle points to the A in Normal at 2000 rpm and around the O in Normal at a warm idle in gear. The needle is heavily dampened (so to react to changes) but is still a worthwhile modification.
I would say that the dash cluster removal is rather involved and not for the faint of heart. In fact, living without the resistor modification is really acceptable when you consider the gauge is dampened. If my wife would allow it, in retrospect, I'd have just done the tee and added the chime to the factory gauge but installed a real 270 degree mechanical gauge. And not touch the dash.
From: rah@netcom.com (Richard Hyde)
And now! What the manual says about the infamous OIL
PRESSURE GAUGE!....
"When the engine oil pressure is normal, the oil pressure switch is closed (short circuit), allowing current flow through the 20-ohm resistor on the cluster flexible circuit into the gauge which drives the pointer to a position slightly above midscale. The switch opens (open circuit) when oil pressure drops to a critically low level (4.5 - 7.5 psi) causing movement of the pointer to or below the "L" band."
"NOTE: The pointer of the magnetic gauge will remain in it's last position when the ignition is turned off. It will move to the correct (or actual) indication whenever the ignition is turned back on." Looks grim..
#2-----------------------------------------
It looks like the cluster is trivial to remove. You have to remove the "ash receptacle"
first. Open the "ash receptacle" and remove two screws attaching the "ash receptacle" and instrument cluster trim panel. Remove the ash receptacle assembly.
(Oops - first remove battery ground cable)
Next, unsnap the cluster trim panel by pulling rearward around the edge of the panel. Depress the hazard warning switch and remove the cluster trim panel.
Remove the four screws securing the instrument cluster to the instrument panel.
Vehicles with automatic transmissions require that the PRNDL indicator be removed.
Remove the two screws attaching the PRNDL to the cluster and slide the PRNDL down and out of the cluster. Leave PRNDL connections
undisturbed.
Pull cluster assembly rearward to gain access to speedometer cable. If there is insufficient access to disconnect the cable at the instrument cluster, it may be necessary to disconnect at the transmission and pull the cable out far enough to disconnect at the cluster (!)
Unsnap the two wiring harness connectors and remove the cluster.
-------
reassembly is the reverse of the above except you must:
"Apply approximately 4.8mm (APPROXIMATELY 4.8mm???) or 3/16 inch diameter ball of silicon dielectric compound (D7AZ-19A331-A (ESE-M1C171-A)) or equivalent in the drive hole of the speedometer head.
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'91 EB, 4dr, 2wd
www.grimmick.com
hank@grimmick.com
[This message has been edited by Hank (edited 03-15-2000).]
