Archived No Oil Pressure @ Idle !

[raf2000]

Almost 200K on my 2000. Came out of gas station about an hour ago, put truck in reverse and check gauges came on. Saw ZERO oil pressure - yikes. Shut off engine, checked oil OK, restarted and drove about 4 miles. Oil pressure lower than normal now and it drops to zero in gear at idle and the check gauges comes on. If I put truck in park or idle, it stays barely off the drop off point. Seems like it reads either 20 (?) or so or nothing. It justs falls to zero when it gets below the left white line. Oil pump goner? Any histories of these things going out? How much $$ and PITA is that to change. Thanks all. .

 

[bmoeller]

Before tearing anything apart, get a mechanical oil pressure gauge. Could just be a bad sending unit or gauge.

 

[nps]

Before tearing anything apart, get a mechanical oil pressure gauge. Could just be a bad sending unit or gauge.

Agreed. There is a TSB on oil pressure. The dealer used to change the sender unit, but DC decided that the new fix was a reflash to cause the gauge to read normal when the pressure dropped out. Not much of a fix, but lends to the belief in the reliability of the oil pump huh.

 

[raf2000]

UPDATE: Drove the truck about 40 miles this afternoon and observed the following. Start cold, pressure reads around 60. Steadily drops below 40 and will not read above 40 again until another cold start regardless of engine speed. I stopped by the dealer, the mechanic let me install the test gauge after he burned his fingers a few times. I installed it on top of the oil filter housing at the 1/8 inch npt fitting. Dash reads about 20 psi when the Snap-On mechanical gauge says 21 at idle in gear. When I rev the engine, pressure goes to 40-70+ almost instantly on the test gauge and only gets to about 39ish on the dash gauge. When the gauge slowly drops down to about 21 indicated, it suddenly drops to 0 like I turned the key off , lights the check gauges and dings. This happens almost every time I let off the gas and the engine returns to idle speed (in gear) when the motor/oil is hot. When in neutral, does not happen. I have guessed that the factory ECM program for the oil pressure gauge drops to 0 when it sees 20 or less psi? I have a virgin 2000 auto ECM. Dealer suggested a new pressure sender at $200 for the part. Going to call Cummins parts counter tomorrow and ceck price. Anyone an expert on this subject or had a similar experience?



FYI, oil pump is about $192 @ Cummins (Cummins PN 393 7404 at least for my engine SN) and almost FOUR hundred at the DC parts counter. . Parts guy said he doubts an oil pump as do I.

 

[big barney]

Oil pressure sender part #4088390NX from Cummins. It costs around $70. 00 plus a core charge. No reflash required, works perfect.

 

[raf2000]

That sounds pretty good. Where exactly is the sender?

 

[big barney]

Right behind the Fuel filter. At least it is on my 1999. I changed out the fuel filter at the same time. Made it a piece of cake.

 

[raf2000]

My 2000 has a filter housing, removing the cartridge inside allows no difference in accessing anything behind it. I ordered one from Cummins and got it today. Will install in the morning. Pressure now reads about 40-75 psi BEFORE I start the engine, and then drops to zero and stays there until next cold start. Gotta be the sender. That part number seems to be discontinued, I got a #3408428 for $75 and no core charge.