Another problem I'm having with my 85 4Runner is low oil pressure indicated on the factory SR5 gauge.

No oil lights or anything like that, just a low and sluggish reading on the gauge. Pressure is just barely within operating range (actually between the first and second lowest lines on the gauge), but it takes a 30 seconds or more for the needle to raise up to this point. Revving the motor helps it raise up more quickly. I am thinking its either a bad gauge, clogged oil pump screen, or bad oil pump.

I fired up my 86 parts 4Runner and the oil pressure gauge immediately read a higher pressure, so I know its not a consistant low gauge reading.

Any ideas on what steps I should take next? Thanks.

Man...I guess I shoulda read this before making the long winded reply to your other post. Low oil pressure, funny emmissions out the tailpipe and weird noises. Do you happen to know any of the rigs prior history such as maintenance or major work performed by previous owner? The 22R series oil pumps rarely if ever go far enough out of spec to cause low oil pressure. Generally the low reading is a sign of worn bearings. As the clearances open up the pressure drops. I doubt the oil pickup screen would be plugged unless the PO ran sludge for oil...or somehow left the valve cover off and parked under a pine tree. Of course if the drivers timing chain is missing then that is a source of screen obstruction. Time to do some serious investigating on your motor. I highly suggest the compression check and acquiring a mechanics stethascope (SP?) to try and localize some of the noises. Prepare yourself for some sort of repair. May be partial tear-down in the future...or even a major overhaul. But dont let that discourage you. Noises have funny sources- for example a baseball card in the spokes of a bicycle can cause a mechanic to have a heart attack. Best dig into this as soon as you can. Hell if you werent 3,000+ miles away Id lend ya hand....that 86' parts 4Runner sounds interesting LOL. ~Darin <img src="/forums/images/graemlins/baby.gif" alt="" />

Thanks for this reply and the one on my other post. Yeah, I need to do a compression check asap. It is hard for me to imagine the motor not being healthy considering how it fires right up and runs smooth as silk (when idled up a bit). I know nothing of its previous history other than I am the third owner, first having it 14 years, second having it 4 and only putting 4k miles on it in this time). The oil was black as black gets when I changed it, but it did not seem at all gummy. It actually seemed a little thin, but it was consistent with no indication of mixing with other fluids. The fuel filter had been replaced at some point before me and the "dirty" fuel in the filter wasn't very dirty. So, I am going to poke around some more. I want to get the truck on the road and moving before I put too much money into it. Right now, it is awaiting a donor 3rd member and all the motoring its done has been up on jack stands.

However, here's the ticker. When I looked at and started the truck before buying it, it smoked very little even when revved high. After towing it home, it began smoking much more. I'm still thinking about that one......

*Well even an engine on its death bed can run excellent and fire right up. My original engine in the 88' would start as soon as the key rotated...ran strong and smooth. Unfortunately there was this ever increasing noise that was kinda annoying. Kinda sounded like someone hammering a huge block of aluminum....turned my #3 rod bearings were literally gone. Engbldr ended up with the mill when I got the Gen1 motor. <img src="/forums/images/graemlins/smile.gif" alt="" /> So just because shes strong at start-up dont rule out any causes yet. The low oil pressure makes me think the bottom end may be weak...and as far as the no smoke when test driving/buying...and lots of smoke now subject: There are all kinds of tricks out there to make something seem fine and dandy and mask the problem for a short amount of time. Ever heard of sawdust in a gearbox? Quiets them right up...but when they let go boy howdy there aint no "I didnt hear a thing" about it. lol
Run your tests and see whatchya get...I have a tendency to point to larger more severe problems before starting simple...so keep that in mind. Im far from being an expert on these motors but tend to pick up some knowledge here and there. Let me know whatchya find out with the testing.
~Darin <img src="/forums/images/graemlins/baby.gif" alt="" />

Yep, I worried about the PO masking problems before I saw the truck and then I met her. I don't think she would've known how to change the oil herself so I don't think she did anything sneaky. I plan on beginning the investigation soon............

Switch the oil pressure senders between the two trucks. Those things clog up and give reduce pressere readings.