PanzerAce Posted May 23, 2009 Share Posted May 23, 2009 So first question: is there anyway to test the function or "reset" the oil pressure relief valve without removing the oil pump from the block? I think some of the old oil gummed it up (after my oil change, oil pressure has been low at anything other than idle). (On a semi related note, where is the oil pressure sensor located?). Second (completely unrelated) question: Does anyone know the bolt size/thread pitch for the vacuum assist post on the #6 runner on a mikuni manifold? I think I've got a vac leak in my booster system, and I don't really have time right now to pull the entire thing apart, so I'm willing to just cap it off for now. On the other hand, if feeling the brake peddle pulse while idling with the brake depressed is indicative of something other than a vac leak, can you guys let me know? Thanks in advance guys. Quote Link to comment Share on other sites More sharing options...
Tony D Posted May 24, 2009 Share Posted May 24, 2009 Take it apart, clean it and that's about all you can do. The pump is an internal relief, if it's malfunctioning you get low pressure everywhere downstream. VW's didn't do that, they regulated pressure off the back of the main oil gallery, so the pump pushed all the oil to the engine first, before dumping any to the sump. Guys put relief valves on the pump covers on them to keep from blowing oil filters (which L's can do if you crank the relief valve up!) Oil pressure is taken off the side of the block next to the oil filter---it is UPSTREAM of the oil filter, it is NOT the pressure your rods are seeing! If you have a cheap filter with a bad bypass internally that doesn't open when it's clogged...rod city man! Usually low oil pressure is a sender thing. What kind of numbers are we talking about? I'd put a MECHANICAL gauge in where the stock sensor is positioned, and VERIFY any readings you get. Cannon used a 1/4 NPT if I remember correctly, if not that, 3/8npt. Though the Japanese one is BSP, ---it fits, the threads are close just use a lot of PST Sealant and it should seal up fine. G'Luck! Quote Link to comment Share on other sites More sharing options...
PanzerAce Posted May 24, 2009 Author Share Posted May 24, 2009 Cool, thanks man. Numbers wise it's going even screwy-ier (which is now a word) than when I first posted. It was reading zero psi, but a visual check through the oil cap showed that the spray bar was indeed getting oil (though since I never checked the visual on that when I knew everything was working, can't say for sure if it's more/less pressure than idle should have). Even if it is the sensor rather than the pump itself, I'm probably going to pull the pump and clean it this monday for peace of mind. Quote Link to comment Share on other sites More sharing options...
Tony D Posted May 26, 2009 Share Posted May 26, 2009 I'd go get a mechanical gauge, stick it in a 't' where the stock sensor goes, and VERIFY the pressure reading. 5-10 psi at idle, and around 10 psi per 1000 rpms is considered normal. The FSM has a spec of something like 45psi by 3000rpms or something like that, and in many cases they are well up around 90+psi at 6K... If it's 5-10 at idle, and 45 at 3K, I'd vote for the sensor going kaput. They do it oftener and oftener as these cars age. Quote Link to comment Share on other sites More sharing options...
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