2006 GMC Envoy Denali
I have been getting weird oil pressure readings, sometimes normal, sometimes low. There is plenty of oil in the car. I replaced the oil pressure sensor but still getting the same problems. No noise coming from the engine.
I could not find the wire mesh screen that goes with it. Some models have it and some don’t but without a mirror or small camera I couldn’t make sure. Then I heard those screens were not introduced until the 2007 model year. Can someone confirm or deny that fact?
The connection seems to be ok to the wiring. It is possible I didn’t screw down the new sensor as tight as I could to the block because it was awkward to get to. I think it is flush but if not. would this affect the reading?
Lastly if everything is right, no screen, sensor racheted down, electrical connector tight, what should I check next?
“Why is my oil pressure low coming on every time I
let off of the gas? It tells me to stop engine, as
soon as I give it has the light goes off and it’s fine”
and answers like:
“GMC 2003 to 2008 had this oil pressure problem. I bet you have about 160k - 200k miles on it. I’ve done just about every thing to my 2005 tahoe and finally found out what was causing the low oil pressure. Ready, put your seat belt on…I’m going to give you a list to check from cheap to the most expensive to fix this problem. Remember do the first and if not working go to second item on list. 1) change oil pressure sensor, it’s cheap, look like plastic spark plug, only one, back of engine. 2) use thicker oil for high millage car 3) replace oil filter 4) replace oil pump filter screen 5) replace the whole oil pump assembly 6) Ok sit down for this one. This is going to be the most expensive. During the time period of model, the GMC had or used defected cam bearing… Well the bottom line is your cam bearing is worn out, meaning no more v shaped groves to keep the oil flow going when idling. Well there you have it. That’s #6, replace the cam bearing, half as much as engine rebuilt.”
Just for grins, borrow or otherwise acquire a mechanical pressure gauge. Install it so that it replaces the oil pressure sensor. Use a hose if needed. Next run the engine up to normal operating temperature. Then read the actual oil pressure at idle off the mechanical gauge. If it is within specs, your wiring is at fault. Unless of course your new sensor is a piece of crap made in China or India. In that case the new one may be bad right out of the box. If so, buy a made in USA or a German made sensor & install that one.
I’ve done quite a few google searches and watched many youtube videos. The real issue is the ambiguity of if there is a screen present or if the problem is sludge, an open vent in the oil pump or something else.
“I have been getting weird oil pressure readings, sometimes normal, sometimes low.”
This is just too vague. It could well matter if this only happens at high speed, or when you stop at an intersection or immediately when you start the car up or only after you have been driving a while… What I suggest you do is find a forum where Denali owners hang out and ask there, for example:
Is it the dash gauge by chance reading erratically?
My daughter’s 2003 Chevy Cavalier had a speedometer and gas gauge that started giving inconsistent readings. Read online that many GM products from that era had gauge problems due to a design flaw with, I think think they were called, stepper motors in the gauges. Sent the cluster in to have it rebuilt and no more problems.
Do a Google search on 2006 GMC Envoy gauge/instrument problems and see if it was still an issue with your vehicle.
So I used the Envoy to run an errand today. Pressure started out low but after a few minutes it got up to 40 psi and at worst in idle dropped to 36 psi. It looks like it is working now. Someone who knows how these sensors work, is it possible that it needed to run a few miles at full pressure for it to read the oil pressure right?