tresguey

Does an LQ4 have a strainer in the oil pressure sensor. Have good pressure with a mechanical gauge at the oil filter, low pressure with a mechanical gauge where the oil pressure senor is.

tresguey

Reason why I am asking is, 2003 Denali XL low oil pressure warning on dash at idle....zero valve noise. replaced the friggin oil sensor 3 times with the same warning at idle, them that is when I checked both locations with a mechanical gauge.

tresguey

Anyone have any idea on this?

Karlw

iTrader: (5)

Have you replaced the sensor?

G Atsma

He says above (post#2) that he replaced it three(3) times.

Karlw

iTrader: (5)

Whoops, I read that as he checked the pressure three time with a gauge. Anyway, its time to start checking wiring and voltages. Good news is you have good oil pressure.

Karlw

iTrader: (5)

Guess I should also ask, what did your pressure gauge read at idle?

tresguey

I have 5.2 volts going to the sensor. Pressure at idle at the filter on the block is about 25 psi, at the top its about 11 psi at idle. Both pressures will clime as I give the vehicle more rpm.

I was looking at the oil system schematic in a service manual, from what I see I think oil flows from the pump, then in and out of the filter, then through a galley where it has a tee where the sensor is located, then off to the cam bearings. Since oil does not compress I would have to guess that there is a blockage in that tee somewhere. This is why I was asking about the strainer before the filter. I was told the LQ9 has one that can be replaced. I was wondering if this is true with the LQ4.

Now I hear zero noise in the valvetrain, I would assume if there were an issue with oiling I would hear something. Also with the low oil pressure warning that appears on the data screen in the cluster. Is this signal coming from the computer or the cluster itself? reason being is the gauge in the cluster seems to be off by about 5 psi according to the mechanical gauge, and that stepper motor was replaced along with all the other stepper months before I changed the oil pressure sensor.

tresguey

Anyone have any ideas?

jimmyp3353

iTrader: (3)

Oil goes up the pickup tube, through the pump, down the block, into the filter, out the filter, then up to the oil pressure sender. The oil galley barbell is what directs the oil out of the filter and up to the pressure sensor as opposed to back down the block towards the pump. It acts sort of like a wall between the flow in and out of the filter. could be you have a bad seal on the galley barbell which is bleeding oil back to the inlet of the filter causing the pressure to drop after the filter. May be 100% wrong, but just a thought.

tresguey

Hmmn, think I will replace the barbell, what do I have to lose. It makes sense to me.

Anyone know how difficult replacing the barbell will be engine still in the vehicle?

cookseyb

It's behind the flywheel-torque converter not sure you can replace it without pulling the trans and or engine. Not sure you can even see it with the engine in.

jimmyp3353

iTrader: (3)

You have to remove the trans and rear cover. There is a plug in the side of the block next to the oil filter that you can remove with a large allen wrench (I don't remember what size). You can pop the barbell out by sticking a screwdriver in that hole and pushing the barbell out.