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oil pressure sender keeps failing

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mat in tn

oil pressure sender keeps failing

i have had three senders fail in as many days. finishing up a frame off resto of an 86 l b with 351ho. i have been reading on this site for two days since i discovered it. first time ever joining in any site but decided to because i feel right at home in this arena. just a little stumped by this issue

Gary Lewis

Re: oil pressure sender keeps failing

Administrator

Matt - Glad you joined.

And you will fit right in, I’m sure. I saw that because you missed the request to go to the New Members Start Here folder and introduce yourself. And about half of new members do.

On the oil pressure sender, how are they failing? Are they leaking? Or also they suddenly give the wrong reading?

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

mat in tn

Re: oil pressure sender keeps failing

well let me start by saying that i have been reading many of your answers to other posts and that has had me looking at many things over the past few days. unfortunately i answer one and get three more to answer as a result. i started with a new standard PS60 oil sender on this resto , and it worked . but as i was installing many things in sequence i can not say how long it was before i noticed it not working. replaced it again and it worked then failed in short order. i checked grounds to the cluster and noticed temp reading high but not overheating. noticed fuel reading below e so i put 5 gal in. still reading low. either tank. next i tried another icvr off the shelf. no change. added an additional ground from icvr ground screw to firewall and now the temp shows correct. sufficed to say im chasing something not wanting to be found. these trucks are what i do and yet this is a first for me. however i subscribe to the old line 'there are not stupid questions' but there are stupid answers. haha

Gary Lewis

Re: oil pressure sender keeps failing

Administrator

I'm guessing that you have a wiring problem. Pull the wire off the sending unit and ground it. The gauge should go to the far end of the scale if the wiring is good. If not, it is a wiring problem.

And, you can do the same for the temp or fuel level gauges. All three are driven by the same ICVR and all three use the same scale and resistance range of sender. So you can actually use the temp sender to run the oil pressure or fuel level gauges for testing purposes.

Gary, AKA "Gary fellow": Profile

mat in tn

Re: oil pressure sender keeps failing

yes i am certainly looking at the wiring at this time. i have proven the guages as you suggest and have proven them from the sender ends to include full circuits also. one thing that i have been questioning . i have cluster on the bench and out of the way. looking at cluster plug and identifying the resistor wire i noticed there is another black wire paired in the factory crimped terminal with it. two resistors? as to an earlier writing of yours , yes trying to get an icvr output voltage using a dvm can give you a migraine .

Gary Lewis

Re: oil pressure sender keeps failing

Administrator

I don't remember seeing a 2nd wire crimped with the resistor wire, but maybe I missed it?

The schematic below shows there are two R/Y wires coming out of the connector, but not black at the insulator. Could you take a pic of that and post it?

As for the ICVR output, it is so rough that it is surprising anything works off it.

Gary, AKA "Gary fellow": Profile

Rembrant

Re: oil pressure sender keeps failing

In reply to this post by mat in tn

mat in tn wrote

I checked grounds to the cluster and noticed temp reading high but not overheating.

I had this same issue after rebuilding the 302 in my '84. I screwed around with a bunch of different things, but the temperature always checked out fine with a IR gun. However, the gauge always read high, but not overheating. In my case, it turned out to be the parts store sender I had installed. I went to the local Ford dealer and ordered an OEM replacement, and bam, my temperature gauge worked perfectly after that. At exactly 195F the gauge was reading straight up in the middle (I assume this is what Ford had intended).

Can't help with the oil pressure sender though. My parts store senders worked fine, on a couple engines.

1994 F150 4x2 Flareside. 5.0 w/MAF, 4R70W, stock.
1984 F150 4X2 Flareside. Mild 302 w/ 5spd. Sold.
1980 F150 4X4 Flareside. 300i6 w/ 5spd. Sold in 2021.
1980 F100 4X2 Flareside. 351w/2bbl w/NP435. Sold in 1995

Gary Lewis

Re: oil pressure sender keeps failing

Administrator

Corey - That's good to know. I'm sure that Ford intended the gauge to read right in the middle at 195F as that's the temp 'stat that all of the vehicles had. So that makes sense.

Gary, AKA "Gary fellow": Profile

Rembrant

Re: oil pressure sender keeps failing

Gary Lewis wrote

Corey - That's good to know. I'm sure that Ford intended the gauge to read right in the middle at 195F as that's the temp 'stat that all of the vehicles had. So that makes sense.

I find the Bullnose gauges work quite well when everything is operating as it should. My temp and oil pressure gauges would show fairly small fluctuations. People often say that they're just "dumb" gauges and not very accurate, but my opinion and experience is the opposite.

I don't think it hurts to go a bit overboard...even a bit OCD, when it comes to proper grounding in these trucks.

Gary Lewis

Re: oil pressure sender keeps failing

Administrator

I agree - when everything is "right" the gauges work well. And in my experience a replacement ICVR helps that a bunch. My gauges never glitch, and you can map them very well to the aftermarket gauges - although the factory gauges are slow to react since they are really just thermometers with heaters in them. So it takes a while to warm up or cool off.

Gary, AKA "Gary fellow": Profile

Gary Lewis

Re: oil pressure sender keeps failing

Administrator

In reply to this post by Rembrant

Oh, I forgot to comment on the grounds. And I agree - there's no such thing as too many grounds. And Ford apparently figured out during the 80's that they didn't have enough of them, so the Bricknose and later trucks have progressively more and more grounds.

Did you see the diagram of the grounds I installed on Big Blue?

Gary, AKA "Gary fellow": Profile

mat in tn

Re: oil pressure sender keeps failing

when in doubt add a ground. making sure that main grounds are proper and clean. i generally have one frame off job going at any given time. one thing to be ocd about is grounds especially on newly restored / painted parts. paint is a much better insulator than conductor. i paint everything. therefore i use thread cutting screws and paint cutting washers often . my first thing checked was looking for grounds. thats why i added one directly from the icvr ground to the firewall. and it did change the temp sender . it really seems as if the oil pressure senders are acting like fuses. im looking for what could cause such a thing. over current is where my mind is .

mat in tn

Re: oil pressure sender keeps failing

oh yeah one more thing. this is where i fall on my own sword. this is the very first time i have ever participated in anything like this. i am as lost as last years easter egg with a computer. i dont know where anything is. how to post photos. etc. there are NO photos on my laptop. im still looking for the damn exclamation point..... im a carburator man ...

Gary Lewis

Re: oil pressure sender keeps failing

Administrator

In reply to this post by mat in tn

Have you tested the senders after then quit? You can put air pressure to them and see if they are open at some point.

And I agree with you on grounds. I paint or powder coat everything, and that messes up the factory grounds in a big way. But the factory grounds weren't really enough, so I added my own. Serious overkill.

Gary, AKA "Gary fellow": Profile

mat in tn

Re: oil pressure sender keeps failing

yes after each fail i verified by connecting ohm meter and applying air pressure. i even did that with new before installing the last one to prove the test viable. that sender lasted one ''warm up ''of the engine at best as it did not work after that. im convinced that something is taking it out but im running out of theories. i do have a 93 alt and alt harness conversion if that gives any light.

Gary Lewis

Re: oil pressure sender keeps failing

Administrator

Does the gauge work properly and show the right pressure for the time the sender works? If so, then you aren't pulling too much current as the gauge is in series with the sender - the same current goes through each.

And, the same resistance wire serves the oil pressure, water temp, and fuel level, so if the latter are working correctly then the resistance wire is probably in the circuit.

Are you buying the same brand sender from the same place? Maybe they got a batch of bad ones?

Gary, AKA "Gary fellow": Profile

mat in tn

Re: oil pressure sender keeps failing

well the oil gauge showed about 1/3 of the gauge reading. this is tested against the mech gauge that i ran under the hood for break in period showing 55psi. the temp showed 3/4 gauge while ir gun showed 185+_ at the intake side of thermostat. fuel gauges still read under empty even though i added five gal to check this. i realize that i may be chasing multiple issues or i may be dealing with a common one. im trying to go from common to specific . when ops is jumped the sender goes full gauge so that makes sense about it not being overcurrent by only showing part gauge.

mat in tn

Re: oil pressure sender keeps failing

glad to say the oil pressure issue "seems" to be resolved. not much time lately for the truck but i am back to it. i discussed the senders with the mgr at the parts store and we ordered a motorcraft and it has been in and working for three weeks at least now. this is a great example of not all are equal. i know to use motorcraft on my fords but its an oil pressure sender for gods sake. thats on me. now to find a coil worth using

Gary Lewis

Re: oil pressure sender keeps failing

Administrator

Glad you got it fixed!

Gary, AKA "Gary fellow": Profile

reamer

Re: oil pressure sender keeps failing

Remember about grounds, though. I installed over 10 new grounds in my '73 Bronco, Motor to frame, Body panels to frame, Tailgate to frame, (license plate light), Floor pans to frame, Dash to kick panel, Kick panel to frame. Frame to Battery, Tank skin to the body, Core support to frame. . I have very bright stock headlights and side markers.

1986 F-150 Flareside 4x4, 351, 4-v, ZF5 speed. AC, Cruise, Tilt, Slider, Digital clock, Radio, Lariat seat, Pwr doors/locks