Today I installed an aftermarket oil press gauge (Auto Meter), but when I turn the ignition on (not starting) the needle goes straight to the other end (100 PSI). I am 100 % sure I wired the gauge correctly. All wires and connections are okay aswell. I did not replace the oil pressure sender with the one Auto Meter included with this gauge yet. Okay, might be pretty obvious, but could this be it? Is the stock oil pressure sender so much different in ohm range than the one that came with the gauge? To me this looks very similiar to a common problem with fuel level gauges. Those are resistor gauges (Ohms). Do oil pressure gauges work this way also? When your tank unit is bad, and the resistence got way too high, the gauge will always read FULL. If I'm going to replace the oil pressure sender, do I need to drain the oil? This is on a 231 V6 but I believe it's exactly the same on a 350 V8. ps. I did try to start the engine to see if the gauge would give any normal readings. Just went through a transmission swap and didn't fill the tranny with oil just yet. So I didn't crank the engine.
I recently added an after market autometer gauge as well - you need to install the autometer oil sending unit that they supplied you with - I did and my gauge works great. If you have stock rally gauges and want to keep both gauges functional then just install a tee and hook up both the stock and autometer oil sending units (did this with my car and both the stock and aftermarket gauges work great)
Thanks for your answer. I'll replace the oil pressure sender tomorrow. Did you need to drain the engine oil? Or is there no other way to reach the sensor than taking the oil filter off (and therefor draining the oil)?
You will have to drain the oil as the oil sending unit is towards the bottom of the engine. If you install a tee with both sending units you will probably have to take off the oil filter as well so you have enough room to install everything (I had to do this - not a lot of room in that area!)
You don't need to drain the engine oil. When the engine shuts off, the majority drains into the oil pan, below the pressure sender. Just replace the oil filter after you install the Auto Meter provided oil pressure sending unit. Always use the sending units provided with any and every aftermarket gauge. You only need to replace what oil leaks out, and it won't be much. Check your oil level after you verify gauge operation, as you normally do, and for any leaks around the sending unit. As the commercial says, "Think with your dipstick, Jimmy!" :TU: http://www.youtube.com/watch?v=pZQ_eTMHgHc http://www.youtube.com/watch?v=Mj5ms9PJDNY "outtakes" http://www.youtube.com/watch?v=A-sn6saUp6Y&NR=1 ElectraJim
Thanks guys. I replaced the oil pressure sending unit today. Didn't need to drain the oil. Didn't need to take the oil filter off either. I took the alternator and alternator bracket out of the way and could reach the sender. The oil pressure gauge is now behaving normal. Didn't start the engine yet, so no readings yet. The needle now sits slightly under the 0, with contact on it goes to exactly 0. Installed a water temp gauge also, so I replaced that old sending unit with the correct one too.
Chris, do you recall the specs on the tee you bought ( threads). I want to keep my stock unit and the guage pack operating. Would teh local NAPA know the size . Always a worry that I'll get the wrong thing and need to go back. Thanks, Steve
>>I honestly don't remember the exact specs of the tee I bought (and my Buick shipped off for North Carolina last night so now I cannot check anymore) but what I did was remove my stock rally gauge oil sending unit, went to Home Depot to their plumbing department, and tried a few different fittings and tees until I found what fit best.
