I was just wondering what everyones oil pressure runs at? When I am at idle it is usually at 40 and when I am cruising down the road at about 60 mpg it runs about 50 and if I get on it alittle bit it about hits 60.
What is your oil pressure??
- Thread starter jd8181
- Start date
Isnt the oil pressure gauge buffered by the PCM? In other words, the oil pressure gauge will always read 40psi at idle and rise to 50-70psi when you are driving. Its not your actual oil pressure.
Mark20
Member
- Dec 6, 2011
- 1,630
On the 4.2L its just a pressure switch to tell the computer there is minimal oil pressure. The computer then drives the gauge based on RPM. Are the numbers even realistic? I don't know. The 5.3L has a real sending unit though the computer may dampen the display value so you don't see every fluctuation.
A couple months ago Harbor Freight had gauges on sale for about $15 so I bought their oil pressure setup. What I'm finding is the only time it compares with the IP gauge is at ~2000 rpm and the engine is warmed up. Then both read about 50 psi. When first started the HF gauges will read in the high 70's and when the oil is warmed and at engine idle the oil pressure is 10-15 psi. I didn't have a good comparison gauge to check the accuracy of the HF gauge. Directionally, however, the oil pressure behaves like my wife's car that also has the gerotor type oil pump. Her car's oil pressure is in the 70s when first started and idles around 20 psi.
My IP gauge is always greater than 40 and always less than 60. My guess is if the oil pressure was actually displayed at 20 psi at idle there would be a flood of people complaining.
My IP gauge is always greater than 40 and always less than 60. My guess is if the oil pressure was actually displayed at 20 psi at idle there would be a flood of people complaining.
That's the right answer.AbsoluteZero said:
On the I6 engine, the displayed oil pressure is a fantasy number MADE UP by the PCM to convince the average owner that there's some life beyond the firewall. I don't know how the designer was able to sleep at night knowing the system was lying continuously like that. Management must have tied them in their chair and forced them to do the unethical thing. All the gauges that read around straight up (12 o'clock) for normal operation are subject to PCM "smoothing" of the real data, which you can see with a scan tool or Scangauge. But the I6 oil pressure gauge is in a class all of its own with the full-up LIE being displayed. The V8 data is smoothed and averaged, but at least that system uses a true sensor in the circuit instead of a simple (cheap
) on/off switch.Well mine runs about 50-60 psi while driving and at idle stays about 40 psi, ofcourse that is when the engine is cold... after I have driving it for at least 15-20 minutes if a came to stop light the "LOW OIL PRESSURE - STOP ENGINE " warnings display and I just give her a little gas while I keep pressing on my brake to kick up my RPM to tell the PCM that everything is fine... I have replace both iddler, tensioner pulley, also I clean my trottle body in and out, replace the sensor/sending unit right about the oil filter and the daing thing keeps acting up! my next idea is probably that my oil pump is giving up, but I'm afraid to spend the 80.00 to replace it and that will also not solve my problem...
Not trying to highjack this post... I just need it to let it out one more time.
Not trying to highjack this post... I just need it to let it out one more time.
Holy crap. Thats actually a little scary. Hate to think what actual pressure trips the "low pressure" logic ("switch" would just be wrong here).
ScarabEpic22
Member
- Nov 20, 2011
- 728
Yup, the I6 lies to the end user on the oil pressure, but at least it doesnt on engine temp. V8s are more accurate on oil pressure, but lie on temp, GM should have changed the cluster to say 195F straight up and down. And Ive seen my I6 temp go from 201-207F on a normal day and just on Monday watched the SS go from 185-197F on a road trip in 35-50F weather. Ugh, frustrating as heck.
From what I could find the specs are 12 psi @ 1200 rpm. Agree on the accuracy of the HF gauge, especially at the end points. I would have liked to check it against a known good gauge but don't have one available. I installed it more as a curiosity factor as a check against the IP display.Mark20 said:
As mentioned the characteristics of the Envoy's oil pressure are similar to the wife's 3.6l SRX. The SRX actually has an oil pressure sender but not an oil pressure readout on the dash. I'm reading what's reported to the PCM.
davenay67
Member
- Jan 16, 2012
- 217
10psi per 1,000rpm used to be a good "rule of thumb"....don't see why that doesn't still apply.
People don't necessrily need to know the real PSI of their oil unless there is imminent failure about to happen. The exception if the off-road crowd who need to monitor real PSI on hill climbs and descents.
People don't necessrily need to know the real PSI of their oil unless there is imminent failure about to happen. The exception if the off-road crowd who need to monitor real PSI on hill climbs and descents.