85 Cougar Oil Guage Issue - Questionable Resistor October 12, 2018, 11:12:48 AM My wife's 85 Cougar (owned since new) has had a problem for years with the oil gauge reading low at times. I believe the problems is with the in line block resistor installed by the dealer when she purchased the car. Over the years the wire going into and out of the resistor block have basically broken. I would move them around and tape them to the block to maintain continuity. But, now it looks like I need to find a replacement for the resistor block. I've searched the forum and other sites only to find a reference to a 20 ohm value, but I think I recall it reading 25 ohms years ago. Does anyone know of a source for this resistor block or the correct value so that I could build a block or find a suitable replacement (thinking of a ballast resistor or worse case a potentiometer) Quote Selected
85 Cougar Oil Guage Issue - Questionable Resistor Reply #1 – October 12, 2018, 11:56:41 AM Can you post a picture of this part? Quote Selected
85 Cougar Oil Guage Issue - Questionable Resistor Reply #2 – October 12, 2018, 03:42:38 PM Is this an XR7 Turbo? Quote Selected
85 Cougar Oil Guage Issue - Questionable Resistor Reply #3 – October 12, 2018, 09:13:29 PM This is just a regular Cougar with a 3.8 and a digital dash. Attached (I Hope) is an image of the resistor. Quote Selected
85 Cougar Oil Guage Issue - Questionable Resistor Reply #4 – October 13, 2018, 10:06:06 AM Wow, you learn something every day !My 88 that I have owned since new, has read low for at least 20 years.I will make sure I salvage that wire off the parts car and swap it out in the future. Quote Selected
85 Cougar Oil Guage Issue - Questionable Resistor Reply #5 – October 13, 2018, 05:31:24 PM Is this a gauge or a low oil pressure warning light?I have never had the electronic cluster.I can't find an oil pressure sensor associated with the electronic cluster. Only a pressure switch (open/closed). open switch (or open resistor) = low pressure.The only pressure sensor I can find is on the Turbo buttstuffog pressure gauge.The full electronic cluster doesn't show up in the EVTMs until the 87 version. It shows a 22 ohm resister in the circuit.I'm guessing the original resister wire opened up and the fix was the resistor pic you posted? Quote Selected
85 Cougar Oil Guage Issue - Questionable Resistor Reply #6 – October 14, 2018, 02:28:38 AM This is a common issue. As a matter of fact, another member here and I were just discussing it. I'll see if I can get him to chime in. Quote Selected
85 Cougar Oil Guage Issue - Questionable Resistor Reply #7 – October 14, 2018, 02:35:22 AM My 86 had a full digital cluster. It beeped non stopped and drove me nuts. I replaced the sending unit and it still read low. Wish is still had the parts. The fix was to pull the correct sending unit from a junkyard car with the digital cluster. It had that same resistor inline.I remeber the digital dash sending unit was larger then the standard cluster. Quote Selected
85 Cougar Oil Guage Issue - Questionable Resistor Reply #8 – October 14, 2018, 01:52:34 PM Softouch is correct. Your resistor is indeed a 22 ohm unit and was part of a TSB where it was installed in conjunction with the the smaller style sender and this resistor block in place of the larger style.sender. This was done on many cars along the assembly line later on from what I can find...The senders themselves are antiquated 60s technology being used with late 70s/early 80s tech digital dashes wherein the resistance values don't actually jive too well. The results? A low oil pressure chime when pressure is known and confirmed to be good.My own personal example is my 87. Full digital dash. Swapped back to the larger style sender. In fact based upon some research by one of the members here (Cougar5.0) I now run the Autometer 2241... It STILL goes off on very hot, and humid days at around 20 PSI at idle... Awesome.Read the followinghttp://www.foxtbirdcougarforums.com/showthread.php?40473-Digital-Dash-Fake-Oil-Pressure-Gauge-Sabotaged-by-FordBefore I actually swap the entire harness for the very clean one in my garage, I'm going to swap just the lead wire to the sender.Mustangs Unlimited carries it. 4 bux.I've also thought about using the new style senders designed in the late 90s and swapping to that style lead wire.... The new style sender has the same thread size.... Quote Selected
85 Cougar Oil Guage Issue - Questionable Resistor Reply #9 – October 19, 2018, 10:03:14 PM I have been behind in updating this thread. After taking the pic of the resistor I put it back in the circuit. It dinged for a couple days, but then started providing a reading (broken wire). I have been searching bone yards around here but as expected I have not found any donner cars. I expect to have to fabricate something form other resistors - too bad Radio Shack is gone.Thanks to all for the info and the schematic (Schematics really help - see below). I now have a good target for the amount of resistance and other options such as changing the sender out to the autometer. (autometer site has some good info on senders) First I will be looking to get a good resistor in place.Sidebar warning on the value of a schematic - Several years ago (1999?) wife's 91 ford probe had the oil light come on - no one could figure it out - a guy on my GN forum sent me a schematic - found the oil warning light bulb was in circuit for the alternator trigger/excite voltage - replaced the alternator to correct the oil light - would never have figured that one out without the schematic.... Quote Selected
85 Cougar Oil Guage Issue - Questionable Resistor Reply #10 – October 20, 2018, 10:34:35 AM If you go with the Autometer sender you really shouldn't have to add the resistor, but like mine where it dings at a confirmed with an actual gauge at 20 PSI, it couldn't hurt.BEHOLD!!!!!QuoteFord intentionally faked-out the '87-up oil gauge to stop people from complaining about NORMAL gauge movements. With this mod (included at the factory on most vehicles with a gauge cluster), the ONLY normal movement of the needle is from low peg (key off, or key on-engine off, or engine running with no oil pressure) to mid-scale (engine running with 6psi or greater). Any OTHER needle movement indicates an ELECTRICAL fault - usually at the instrument cluster film circuit connector. If the needle drops to 0 with the engine running, the switch diaphragm is leaking from the oil side to the electrical side, which balances the pressure and makes the switch think there's no oil. If the engine is off long enough, that oil will leak out of the switch onto the ground, and it may show pressure next time the engine runs, until it fills up again.TSB 88-05-14 Oil Pressure GaugePublication Date: MARCH 2, 1988LIGHT TRUCK: 1987-88 F-SERIES, BRONCOISSUE: An oil pressure gauge that indicates an erratic or low reading when the engine oil pressure is within specification may be caused by the oil pressure sender (EOAZ-9278-A). The oil pressure sender may not work properly with the magnetic oil pressure gauge.ACTION: To correct this, install a new design oil pressure switch and new design resistor wire assembly using the following service procedure. Refer to the oil pressure switch and resistor wire application chart for the correct service parts.OIL PRESSURE SWITCH AND RESISTOR WIRE APPLICATION CHARTEngine Application Description Service Part No.5.0L, 5.8L, 7.3L and 7.5L Oil Pressure Switch E6SZ-9278-A4.9L Oil Pressure Switch E8TZ-9278-AAll Resistor Wire Assembly E6SZ-9F291-ASERVICE PROCEDURE1. Remove the existing oil pressure sender.2. Install the new design oil pressure switch. Torque oil pressure switch to 10-18 lbs-ft (13-34 N-m).3. Connect the female terminal end of the 20 ohm resister wire assembly to the oil pressure switch.4. Connect the male terminal end of the 20 ohm resistor wire assembly to the vehicle wire harness.PART NUMBER PART NAMEE6SZ-9278-A Oil Pressure SwitchE8TZ-9278-A Oil Pressure SwitchE6SZ-9F291-A Resistor Wire AssemblyOTHER APPLICABLE ARTICLES: NONEWARRANTY STATUS: Eligible Under Basic Warranty CoverageOPERATION DESCRIPTION TIME880514A 0.4 Hr.Now this states for light trucks and Broncos, but was used on other vehicles as well. It may just have a different TSB number for them depending on when it was decided to be done on them....As you can see the resistor in question HAS a part #. E6SZ-9F291-A Honestly though, I don't think it'll make too much of a difference..... In my case; I think it's high time I replaced my lead wire..... Those are ridiculously cheap....https://www.cjponyparts.com/90-degree-repair-plug-with-pigtail-1965-1995/p/HW218/ Quote Selected
85 Cougar Oil Guage Issue - Questionable Resistor Reply #11 – October 21, 2018, 09:55:27 AM I have a harness out of an 88 ranger with a 2.9 for a project for my Bronco II, in the untaping I found several resistors just like that one. I don't know what each's value is but there could possibly be a resistor that would work in a weird place on a harness of some odd ball car.In our small town of Lancaster we have a private electronics store that is similar to what radio shack was in the 90's with miles of drawers and shelves full of components. There one of those small shops that is hard to find, you may have luck searching for one. Quote Selected
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Topic: 85 Cougar Oil Guage Issue - Questionable Resistor (Read 2123 times)
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