No oil pressure

smknram

smknram

"ADICTED"
Joined
Sep 13, 2007
Messages
187
So a few days ago I started my truck to let it warm up, made a quick glance at all the gauges as I do at each start up, everything checked out good. It idled for 10 mins or so then I went a mile to the store (idled a couple mins while I was in the store) then about half way back to the house, I look down and oil pressure is at 0. I continued on to the house and did a quick look over, oil level was full and all the wiring on the gauge and sending unit looked good.

I have not had time to investigate anything until this evening which was 40 mph wind and blowing snow (I'm kind of afraid to drive it to the shop where I can be in the heat and have good lighting until I know for sure it actually has oil pressure) so my time spent was limited. The gauge is an Autometer Sport-Comp Ultra Lite, short sweep, electronic gauge. I was able to check voltage, in which it is getting 12v to the gauge and sending 9v to the sending unit which seems right to me. I checked continuity on the sending unit to ground, which was good. I ohms from sending unit stud to ground before starting truck and got 65 Ohms, then after starting the truck the meter showed open circuit. I shut the truck off and checked again and got 74 Ohms. I'm using a Fluke 323 meter which is auto ranging but I'm not sure on the ohms range of the meter to know if I can trust the "open circuit" when running.

Does anyone know what the Ohms readings should be when running and when off? Is there any simple tests to do with the gauge and/or sending unit to check them? Id really like to think I really do have oil pressure but hate to just start throwing parts at it to figure it out.

Sorry for the long post, I just wanted to get all the information in here that I could to assist in diagnosing the problem.
 
Last edited:
Check with a mechanical gauge. If you drove it that far without oil pressure chances are its the gauge.
 
I recommend a cummins sensor, the Napa one I had only last about 5k mile two times.
 
95cummins5.9 said:
I recommend a cummins sensor, the Napa one I had only last about 5k mile two times.
Click to expand...

I'm running the Autometer sensor in the top of the oil filter housing. I've honestly never messed with factory cummins oil pressure sensors. Does the cummins sensor work on the same principle? Single sensor wire and ground through the block? If so, can I just hook autometer gauge to the factory sensor?
 
Why not just buy a cheap $10 mechanical gauge to throw on the filter housing to confirm you have pressure, then drive to somewhere warm?
 
I intend to do that. I guess my questions were directed more toward figuring out if its the sending unit or the gauge? I can just replace both, but I thought if someone a process of checking both than I would do that and replace whichever is bad.

Other than checking voltage in and voltage out on the gauge, which both seem normal, I would say the gauge itself is fine. The thing that makes me question the gauge is that it doesn't zero out when turned the key on (Needle doesn't even lift up to zero like the others do) but maybe the sending unit could still cause that.
 
Do a Google search on autometer sending units. They don't like vibration, mounted on the oil filter housing of a Cummins is not a low vibration zone. I had to use a grease gun hose and mount mine in rubber on my fender. I was going through sending units every 5 months.

96 3500 5x018 7mm dvs 62fmw
 
I agree, my fuel pressure sending unit from auto meter was not properly mounted which caused it to fail. Sent fuel squirting out the electrical connection side. If at all possible, always do a remote mount.
 
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