Oil presure problems, questions

[CSchafer]

A couple months ago when the bareings in my stock turbo went out, my oil pressure also went down about 3/4 of a mark on the factory guage then were it had been. I thought this was due to the turbo not restricting the oil flowing through it any more. I checked the oil and all is well and no aparent knocks or rattles. When I put on the new turbo it did not fix it, oil pressure guage stayed lower than normal. Figured somthing got knocked around in the oil pressure sender and changed the reading but I kept listening for knocks and checking the oil and no problems. Well yesterday I took it out for the first road trip with the new turbo. I drove about twenty miles down the express way to a park and ride to get picked up, when I got off the ramp it was fine but when I pulled into a parking spot and the truck went to idel the oil pressure went to zero and the light came on. I shut it off imeadeatly and checked the oil agian. everything was fine so I started it up and got nothing so I reved it up a bit (1200 rpm) and the oil pressure came up. I really had no choice but to drive it home so I pulled the fast idel knob and drove home. It acted fine and never lost oil pressure till I got home and pushed in the fast idel and sure enough the light came on so I just shut it off. I was wondering if it could be the sender and were can I put a mechanical guage in it to know for sure (oil pressure port). Or does this sound like a oil pump problem. Sorry about the long post just wanted all the info to be there. TIA for any help

 

[dpuckett]

It COULD be your oil pump, but that's rare in these trucks. On top of the oil filter housing is a 1/8 NPT plug. Plug yout oil pressure gauge into this, and see what you get. Minimum spec is something like 10psi idle, 25psi at rated RPM. Normally theyrun 50psi idle, 75 at speed. Or mine have, with the gauge zip tied to a wiper arm :-laf



If it doesnt sound any different, I would not worry about it.

Daniel

 

[CSchafer]

Thanks, I'll get a mechanical guage hooked up and check it out.

 

[bgilbert]

Worn out engine, time for a rebuild:-laf. Pressure sender is going bad. Has your idle dropped any over the past few months? Once you plumb a real oil pressure gauge at the port next to the turbo oil supply line as Daniel said, you'll see you have plenty of oil pressure at low idle. Sometimes if/when your idle is too low (or just on the low end), your actual oil pressure could be around 20-30psi hot idle (which is within spec of 10psi minimum). This sometimes is low enough to turn the low oil pressure light on in the dash. Also it might not register to the 1st mark on the factory gauge. The factory gauges are pretty much worthless. I love/hate reading about the guys that say their trucks are 'overheating' or their engine is worn out, needs a rebuild because their factory gauge is not registering (oil light on) or the temp gauge is 3/4's across. I just shake my head and tell em, please wipe your @** with the factory gauges. Get a real gauge on there and then see. C'mon we're dealing with Chrysler engineering :-laf and the bulletproof Cummins B Series.

 

[matches]

I agree, my oil pressure gauge was acting up, so I replaced the sender and all was fine. It is on the driver side of the block almost under the injector pump, just behind and below it.

 

[MMeier]

Thanks, I'll get a mechanical guage hooked up and check it out.

Let us know what you find out !

 

[CSchafer]

I got the mech. guage on it. I started it up and it hit fifty pounds but the facory guage was also up higher than it has been. Took it for a drive and when it warmed up, pressure was about 22 idel and 30-35 driving. The factory guage seems to show the same thing and it hasnt droped to zero agian so I can check if the factory guage is out of wack. The pressure is down from when I got the truck and it happen all of a sudden so I'll keep an eye on it but I don't like the looks of it.

 

[Greenleaf]

I installed an ISSPRO mech gauge in the cab because I didn't/don't like how the factory gauge reads. I replaced the sensor twice and became fed up.





The 90 will illuminate the low oil lamp after I drive on the Interstate awhile. The slow idle speed drops down enough to lower the oil pressure.



-S