Question can't find any answers on this on any of the sites but usually 1 out of 5 cold starts my oil pressure is slow to come up about 4 to 5 seconds before it builds pressure what could this be? Its almost like when you change ur oil and theres that delay when you first fire it back up. The truck is a 2011 LML
slow oil pressure
- Thread starter febreze101
- Start date
I've had the same concern after my two engine builds. Sometimes it's fast, other times it's super delayed, and sometimes it doesn't move and sets an oil pressure circuit code.
My one input since I commented originally. A few of my tunes had a slightly lower idle speed, especially on start up. If I run a tune that has a stock idle speed right at start up the oil pressure builds every time and has never set the oil pressure sensor code since.
I haven't tested on an LML, but on LBZ/LMM oil pressure CANbus msg to BCM is buffered, and only registers down about 25psi. The buffering looks to be meant for limiting jumps or swings.
Testing on bench I noticed dash drops from 25 straight to zero, while EFI live reads correctly below 25. So I'd check it on start up against EFI or Tech2 and see if that logic fits.
-K
Testing on bench I noticed dash drops from 25 straight to zero, while EFI live reads correctly below 25. So I'd check it on start up against EFI or Tech2 and see if that logic fits.
-K
I have an aftermarket sending unit in the cylinder right before the oem sending unit and it also reads zero and moves exactly when the dash starts to. Both are zero then then start swinging up quickly but its the pause at zero that has me wondering whats up. After they are up the thing has great oil pressure even when hot, always above 50+ at 2000rpm on the freeway even when the oil is at its max temp. It also does the 20psi dead nuts when hot at idle.
The idle rpm could be a tad low its showing 500 on the dash.
Had a Napa gold in it now, and it has the Mocal oil cooler adapter, this could be causing the slow down on the pressure response but its supposed to be closed until 180 degree's. Just picked up a K&N filter for it going on with fresh oil this weekend. Ill report back.
Yeah I usually stick to delco filter as well. Or mobil.
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I've been running wix premium xp filters, and I've been getting slow to build quite often as well. I mayvtry a GM filter next.
Can’t help but wonder if it’s because the wix and Napa filters have thicker elements making it harder for the pump to push thru at initial startup
I believe it's associated with pop off pressure of bypass, the filter volume and media will change it...
Some filters have a pressure bypass built in. But doubt that's issue. Sounds like a drain back, try a different filter.
Filter that was on the truck was a Rotella, looks like the holes in it are much larger and oval compared to the circular ones of the new GM filter. Post oil change the oil pressure was about 10psi higher. Going to see how it starts in the morning and see if I get any change. I kept a sample of the oil ill send out to see if there is any metal in it and go from there. Ill post a picture of all the filters later on Saturday.