Hello All,

So I've searched all over and found lots about low oil pressure and bad sensors, but nothing really about my specific problem. So here it is...

2004 Tundra

At Start up each morning, especially now that it's getting colder (30˚), I start the truck and the oil pressure gauge doesn't move at all. I can let it run for a minute or more and even drive a little and no still no movement. However, If I start it, turn it off, and start it again I get pressure. It doesn't fluctuate while idling. It move a little up and down with increase or decrease of RPM but that's normal.

Now I took it to the shop and the fellow there replaced the oil pressure sensor but it changed nothing.

So the million dollar question... what else could it be? The only other thing that I can think of that might be a hint. I first noticed this about 3 weeks after an oil change where I switched over to synthetic oil.

HELP.

 

Try using a factory Toyota oil filter if you haven't already

 

Can you explain why you think this might be it? I ask because I live in a remote community in Alaska. Getting a factory filter is not as easy as it sounds. Why would the oil filter affect the pressure in such a precise and predictable way?

 

does your gauge not fluctuate at all on the first startup? even when at higher RPMs, like 3k?

i've heard of the oil pressure reading very low when switching over to synthetic, but eventually the gauge does move, usually hangs around 25-50% when driving. only thing i could guess is that swapping to synthetic dislodged some crud and it's causing the issue - but then again you said you swapped the sensor.

i would hook up a mechanical oil pressure gauge where the sensor is at next to the oil filter, then you will know if you are actually getting pressure or not and then go from there. pressure should be somewhere near 4.3psi at idle/43-85psi at 3k RPMs. make sure to loctite your sensor when you reinstall it.

 

At first start of the day it does not fluctuate at all. Not even if I give it some gas to raise the RPMs. I'll test it up to 3000 tomorrow morning to be sure. I'll consider the extra pressure gauge but at $150 an hour for shop work here, I might wait to see if anyone else has an idea. I've already paid for installation of a sensor I didn't need.

One thing is that it's much worse now that it's cold. Sometimes I have to start it 3 times to get pressure.

 

I don't think restarting is actually changing your oil pressure. It's a mechanical pump and you either have pressure or you don't. I'm guessing you do because it hasn't died on you yet.
The factory gauges are pretty useless, I'd suggest you get an after market oil pressure gauge if you're that concerned with knowing what your oil pressure is doing. You may as well get oil temp and water temp while you're at it.

 

Ps
Factory oil filters online are cheaper than cheapo filters in store and they will ship to your door. Just buy in volume and plan ahead.

 

True enough but shipping to Bush Alaska is all Air Freight so a $10 filter might cost $120 to ship fedex. No roads to here so you can't ship ground. I'll shop around and see if I can find anywhere that will ship USPS. It's the only cost effective option. I just don't see how a new filter would cause the pressure to act like this or at least I can't figure it out.

 

Oem filters were like 6 bucks a pop last time i got them online. I order 12 at a time so even if the shipping is expensive i come out ahead. They are really light, so shouldn't be too outrageous.
The oem filters are supposed to have a check valve to keep them from draining back into the pan. At least that's what I always read.

 

Poor connection at oil pressure switch...?

-Verify oil pressure with: Scan tool data may show oil pressure depending on the manufacturer and scan tool.

-A mechanical gauge tapped into oil pressure.

If engine is not noisy internally, mechanically you may be ok but this is not always the case.

-Possible delay and or poor connection in instrument cluster.

Engine oil weight incorrect...?

 

My suggestion was because of the fact that this started when you changed the oil. I've seen some weird stuff with aftermarket garbage. And because typically, they are cheap and easy to get a hold of. Apparently not in your case though. Your best bet at this point, as others suggested, is to test the oil pressure with a gauge that screws into the port that the sensor is installed in.

 

One thing I might add that I have seen before: Check the harness that goes behind the fan bracket and down to the pressure sensor. If someone did the timing belt and routed the harness incorrectly, it can rub on the drive belt

 

Did you find the problem. My gauge use to be aittle over high and had a vvt valve code come up. Took both out on bank 2 side cleaned then and hooked them up to battery and the oil pressure read normal maybe a little under half way. It's now doi g what yours is doing. Some times it doesn't move other times its perfect. So maybe a sticky vvt valve or something. Did you figure it out?




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Vvt valve? My o5 is just starting to do something weird like this it will now only go to 25% on start up 1/2 when I idle sometimes it seems like it's struggling to , it won't however hold. It goes back down to 25%. I got a new "Napa gold " filter and a new sensor. It went to 1/2 on start and held for a few minutes but back to 25%.

 

So now let's say he has the gage where the sensor was , now what? Is it the oil pump? Mine is starting to do something similar.