Oil Pressure Issues......

[4x4TruckinGirl]

Okay... not the first time oil pressure has been an issue..... I know ya'll are thinkin' I messed something up when I took the intercooler apart, but I didn't. Anyways.... truck is running 100% fine..... but about 5 days ago oil pressure started going low, especially under acceleration.... and it gets LOW...... and then typically comes back but not to normal pressure. I've checked the oil several times... been fine every time, no serious oil leaks to speak of either. Turbo is rebuilt not even a year ago and is spooling fine......

Next question, where is the oil pressure sensor? on the side there by the turbo? Could it be malfunctioning? Any help GREATLY appreciated.....

 

[suv7734]

Sam are you still using the factory oil gauge in the dash? If so they are not very reliable at best. An aftermarket gauge would be best as I'm sure you know, even if you just hook one up temporarily to get some accurate readings. If I remember correctly the ATS/factory turbo system does not relocate the sender so it is under the turbo at the very back of the block. It has a push on connector that can work loose and give varying readings.

 

[69dieselfreak]

get a mechanical gauge cheape form autozone or what ever and hook it up where the old sending unit is and go from there
the sending unit is middle back of the engine

 

[4x4TruckinGirl]

Im getting gauges next week..... tax return check I just wanted to see what ya'll thought about it..... on my turbo on the side there is a little push on thing that I thought was the sensor..... i cleaned it and made sure it was tight on there....

 

[CDX825]

Stock sending unit is a can looking thing about 1.5 inches round on the back side of the valley pan. Should have one wire attached to the top of it.

 

[Shadetreemechanic]

Im getting gauges next week..... tax return check I just wanted to see what ya'll thought about it..... on my turbo on the side there is a little push on thing that I thought was the sensor..... i cleaned it and made sure it was tight on there....

Thats it.

 

[idipwr]

Sam,

The factory turbo sending unit is relocated to the top of the turbo, as the turbo oil feed is drawn from the N/A sending location. I also agree that the factory guage is unrelialable. I work on alot of these trucks and whenever there are oil press questions I always plumb in a mechanical guage to be sure. Hopes this helps.

Rob

 

[NJGearhead666]

I had the same issue as you and lastnight I got home from work took the factory sending unit off the turbo like where your's is and put in a Autometer gauge. truck has 18psi at idle and on the highway at 2000 rpms has 44psi. its a big relief knowing that i was worried over that crappy factory gauge

 

[gonecrazyi]

Mine sits between 25 and thirty at idle when warm, and when cruising sets anywhere from 45-60 depending on the rpm and load.

 

[HammerDown]

Mine sits between 25 and thirty at idle when warm, and when cruising sets anywhere from 45-60 depending on the rpm and load.

What are you using for oil...100wt?
Mine HOT idle 18-20

 

[82F100SWB]

My 6.9 has similar numbers, idling it pegs the stock guage cold, and runs just under half hot. Going down the road @ 2500, the guage is pegged.
On a real guage, that's 65 at cold idle and going down the road(probably where the oil pump's pressure relief is set) and 33-34 or so at hot idle. That's with 0W40 in it, 15W40 produces similar results.

On the 87+ trucks, the guage is really an idiot light with a needle, and the sender is a pressure switch, not an actual sending unit with variable resistance. The guage has a resistor in series with it, so that it moves into a predetermined position in it's travel when the circuit is completed by the pressure switch.

 

[david85]

Before we all gang up on the factory gauges as being crap, check the connector at the oil pressure sensor itself. I had the EXACT same problem with my truck recently and here's what actually happened:

The connector on the oil pressure sensor was lose. When I applied lots of power, the engine would twist on the mounts and vibrate just right as to disturb the weak connection at the oil pressure sensor. Back off, and it was fine. It was almost like clockwork. Hammer down, oil pressure failed according to the gauge. Return to idle, pressure came back up.

All I had to do with mine is take the connector off and use some small pliers to squeeze it down to make proper contact. Problem solved.

Sam, I'm not sure if your truck has the same kind of connector as mine, but have a look at it. I suspect its a really minor thing.

 

[Devilish]

I had a 85 ford truck with a 460 in it. I was towing a GN home from Sac when I noticed that my pressure dropped when I'd apply throttle and come back up when I let off on it. For my truck it was worn mains. I overhauled the engine and applied a few mods then all was fine. Oh, and the most likely reason for the mains being worn was because my truck formerly was used on a ranch to haul a huge trailer full of cattle around.

 

[gonecrazyi]

Im using straight 30wt rotella.

The pressure is a little higher when cold, but overall its stays within the specifid numbers. Ive even double checked with a secong mechanical gauge.

 

[Diezel_Cowboy]

Sam DO NOT get carried away tightening the sensor back into the cast piece. Use a pipe dope sealant or just a minimal wrap of teflon tape since the tape makes the joint tighter. I had exactly the same problem you are having a few years ago so I bought a new sensor and when i put it in I sealed it with teflon tape and when I tightened it down it split the cast oil manifold the that sends oil to the turbo. At that time there were only 2 of those cast pieces available in the state of Ohio from the stealerships and I bought one of them. Seems like they might be kinda rare. Damn cast piece was $70 too. Just be careful with that. By the way here is a pick showing the sensor.