chollenback Report post Posted August 12, 2018 I have 1995 Safari Sahara and the oil pressure sensor was flickering from 0psi to 60psi really bad. I changed oil pressure sensor and it still does samething. I am pretty sure it is shorting out. I have one red wire that attaches to oil pressure sensor and I was wondering if I run a wire straight from oil pressure sensor to dash gauge if that will solve problem. I do not want to cause additional damage. Also, any idea what post I should attach it to on the gauge (what should I look for in regards to labeling)? I would rather do this than take all the plastic off of all the wiring and try to find that way. Thoughts? Share this post Link to post Share on other sites
dickandlois Report post Posted August 12, 2018 Chollenback, I'm sending you a PM with some information that might be real close to you Oil pressure gauge wiring. Rich. Share this post Link to post Share on other sites
chollenback Report post Posted August 16, 2018 Rich, it works perfectly now that I re-wired it. Thanks for diagrahm. Share this post Link to post Share on other sites
dickandlois Report post Posted August 17, 2018 Chollenback, Glad the information was close enough to resolve the wiring. Thanks for your reply - safe travels ! Rich. Share this post Link to post Share on other sites
chollenback Report post Posted September 3, 2018 I just drove 4 hours to greensboro and oil pressure switch jumping around like a Mexican jumping bean. I ran a wire from gauge to frame for grounding. I even ran a separate wire from gauge to oil sensor gauge. I thought it was good and then on the way home i was jumping around again. I now think the gauge is shot but the gauge is an older gauge and not digital. These things I heard really do not go bad. Any thoughts? Share this post Link to post Share on other sites
dickandlois Report post Posted September 3, 2018 Think I remember that you replaced the engine senser. Do you know the voltage output level of the current sender? You might try this link. remember to as if they come with a sensor that will work with your engine. you will need the OEM Gage size and pressure range. The cost of the gauges will very. Not sure as to talk to a tech. https://www.summitracing.com/search/brand/vdo-gauges/part-type/gauges-analog/gauge-type/oil-pressure A possible starting point. Rich. Share this post Link to post Share on other sites
richard5933 Report post Posted September 3, 2018 My understanding is that it's possible to use most any gauge that fits into the dash, but that usually the sending unit on the engine must match the gauge. Different gauges have different pressure ranges, and they operate with slightly different resistances. Check out www.speedhut.com as they have a great selection and it's possible to customize the gauge to get the bezel, face, etc to match your existing gauges. Get the matching sending unit for whatever gauge you buy. The way mechanical pressure gauges work is the sending unit makes/breaks the ground connection. The sending unit is a variable resistor, and the oil pressure is what changes the amount of resistance. As oil pressure goes up or down, the resistance to ground changes. The 12v+ goes to the gauge directly, the 12v- (ground) is fed to the gauge through the sending unit. On some sending units a full ground equals zero pressure and the more resistance to ground the higher pressure reading on the dash. On these gauge the needle will spike in the upper end if the sending unit wire is removed. On other sending units disconnecting the wire from the sending unit will drop the needle to zero. Reattach the wire and bring up the pressure and the ground will be applied to the gauge, bringing the needle up. One common fault is using teflon tape or pipe compound when installing the sending unit. If the sending unit is a single-wire sending unit, the threads in the sending unit must make an electrical connection to the engine block when installed or the gauge won't work. If there are two wires to the sending unit, one will go to ground and the other to the gauge. There may be other wires at the gauge itself, usually to provide power to the light in the gauge or to run other warning lights, etc. Share this post Link to post Share on other sites
chollenback Report post Posted September 4, 2018 I did use teflon tape. You may be onto something. I will remove and fire it up this weekend. Never thought that would cause it. Share this post Link to post Share on other sites
wolfe10 Report post Posted September 4, 2018 1 hour ago, chollenback said: I did use teflon tape. You may be onto something. I will remove and fire it up this weekend. Never thought that would cause it. STOP. Extremely unlikely that teflon tape has electrically isolated your sender. Easy to check. Use an Ohm meter between body of the sender and engine block. I will guarantee that it reads ZERO OHMS. Share this post Link to post Share on other sites
richard5933 Report post Posted September 5, 2018 True - you can easily check that part of it with an Ohm meter. If your gauge is wired like I described with the sending unit supplying the ground to the gauge, you can also run some tests to see if the gauge is working by making/breaking the ground connection to the gauge on the terminal that goes to the sending unit. Share this post Link to post Share on other sites
manholt Report post Posted September 5, 2018 PTFE has excellent dielectric properties! Share this post Link to post Share on other sites
chollenback Report post Posted March 30, 2019 Hey guys it is me again. I went ahead and took of plumbers tape from oil sensor and I even rewired it from oil sensor to dash board oil gauge. Needle still jumps. I think it may be the gauge. That is the last thing left. Does anyone know what the PN is or a oil gauge that will work? I do not see a PN on the gauge. Thanks Share this post Link to post Share on other sites
wolfe10 Report post Posted March 31, 2019 Assuming this is a Caterpillar 3126 (I know the 1996 and newer ones used this engine), oil pressure is a non-issue. If not adequate, it will NOT RUN. Adequate oil pressure is needed to activate the fuel injectors. Let us know the brand of the dash gauge (most are labeled). If you don't know the brand, you might want to post on a Safari-specific forum. PM if you need a link. Share this post Link to post Share on other sites
dickandlois Report post Posted May 7, 2019 I Think this issue has been repaired, after a few PM's . This is the last reply. New gauge is fine. I went ahead and re-ran a new wire from sensor to gauge and it works. I think there is a short somewhere in the old wire. I think it was grounding out. Rich. Share this post Link to post Share on other sites
jleamont Report post Posted May 7, 2019 4 hours ago, DickandLois said: I Think this issue has been repaired, after a few PM's . This is the last reply. New gauge is fine. I went ahead and re-ran a new wire from sensor to gauge and it works. I think there is a short somewhere in the old wire. I think it was grounding out. Rich. Nice Follow up Rich! Share this post Link to post Share on other sites
F347633 Report post Posted July 10, 2020 On 8/12/2018 at 12:47 PM, DickandLois said: Chollenback, I'm sending you a PM with some information that might be real close to you Oil pressure gauge wiring. Rich. Hi Rich, I may be having this problem. Would you be so kind to send me the info as well? I am assuming this is for a Cat 3126. In my case, I would get occasional flicker of the low oil light on the gauge at idle, and occasional spike to 75PSI and light at cruise. We initially thought it was the high performance cat filter after the change, but going back to the same oil filter it has not gone away, and one time the gauge did a dance back and forth from low to high, so I think it is an intermittent connection. Probably covered in oil and soot. Also, may be suspecting slight restriction in the slobber tube extender may be the issue, but the engine never shuts down, goes into limp, or gives a code. Just purrs like a fine Swiss watch. TIA, Chris. Share this post Link to post Share on other sites
dickandlois Report post Posted July 11, 2020 (edited) F347633, Welcome to the FMCA Forum! Personal thought because the gauge jumps, is the possibility of the issue is being caused by a damaged wire. Running from the pressure sensor to the gauge, rather then a corroded connection. A wire tracer like the ones used by IT installation tech. should help fallow the wire from the sensor to the connection at the dash panel. Lowe's sells them as a possible source. TIA Chris, This is a attempt to send a link to the information requested, by the original poster of the problem. I just tested the link and it worked for me. A little like finding the needle in the haystack. https://community.fmca.com/messenger/7828/?do=findComment&comment=19505 This should go to the original message posted about the issue and a copy of the requested drawing. Keep me in the loop ! Rich SMC Safari_Service_ Ctr.pdf Edited July 11, 2020 by DickandLois Tested link Share this post Link to post Share on other sites
richard5933 Report post Posted July 11, 2020 Check the ground connections. Share this post Link to post Share on other sites
F347633 Report post Posted July 11, 2020 (edited) Thank you, The link isn't working, but you've corroborated my suspicions. I'll crawl under there today before heading home. Ahh... The link is a messenger link, so it will only work for you. -Chris Edited July 11, 2020 by F347633 Share this post Link to post Share on other sites
