My Prelude's oil light stays on all the time. The pressure has been mechanically tested by two different people on more than one occasion. All within spec. Within spec on cold start-up, idle, and under high RPM. The car goes onto the high cam and it has never not hit the high cam at 5k, so it's not losing pressure while I'm driving because the vtec solenoid won't work without some serious oil pressure. The oil level has been checked and rechecked constantly. It's full of 10w-40. The car has 148k miles. And of course I've replaced the switch more than once... A local mechanic doesn't know why this is either. The oil screen isn't clogged, pickup is fine (the oil pan has been dropped and system inspected.) I'm so lost. It'll fail inspection due soon due to this. thanks for any help.

 

How many times did you replace the switch and where did you get it from? Is there a relay or fuse for it the switch/light itself?

 

two different shops tried to diagnose the problem which replaced the switches for free. honestly I knew and know it's not the oil pressure switch that is the problem. wherever the shops got the switches from is where it's from. also from the records for my car when I bought it I see it being replaced about 15k miles ago. (However it didn't have this problem when i bought it) But the light used to flicker after driving the car for a long time at idle RPM. I've been driving with the light on constantly for the last month at least. All there is is the oil pressure switch to connect right beside the oil filter.

 

Strange indeed. That would bug me the heck out driving with that on. Have you looked at your oil filters when you replaced them?

 

A true test would be to see how much oil pressure the motor is putting out while at idle and underload. All your oil levels and new sensors could be fine but maybe at 148K miles, you might want to see if the oil pump has any issues. Oil pressure is a very key thing for the entire motor especially in VTEC.

Also I use 10W30 or 5W30.. 10W40 is a lil thick.. remember Honda motors are built with fine tolerances.. I have used 10w40 before with no issues but I usually 10W30.. of course Synthetic.. Mobil 1, AMSOil, Enos.

If you could, can you get the P-code for from your mechanic, they should be able to get it from the OBDII port.. I will look into the other known issues about this, just as a friendly help..

 

BTW, I did see in the original post about the test being done twice so I apologize for now making note in my post..

 

1.) Get a mechanical gauge installed asap - A kit from autozone is about $10-$15 for a mechanical gauge. (Hide it in your glove box). That peace of mind is worth it.
2.) I know some honda motors have 2 oil pressure switches on them - does yours? (I don't think it does)
3.) A common problem w/ some other honda setups (mainly integra's) is that they use cold solder on the back of the dash light. Over time (heat cycles) this connection breaks causing your oil light to pop up. Google to see if this is a common problem with your setup. Fix is usually just re-flowing the solder.
4.) Other way to test this is to stick a voltmeter on it. Should be 0-5v. Watch for burning the crap out of yourself on the exhaust. I think 5v is 120psi? Should be around 2.0v-2.5v at idle. Pull the connector off, connect one end to the connector, the other to the prong on the end of the oil pressure switch.

 

1)Yeah I was looking into a mechanical gauge install but there are mixed opinions on where to get it installed. (To tap into the head, get it from the switch by splicing, sandwiching the oil filter, etc.) Idk which route to take and I've never installed a gauge before.

Btw, my car has seen 5w30, 10w30, all the same result. Synthetic, too. And I've used dye to check for leaks. None. Even replaced a few trouble gaskets.

2) It only has one.
3) Haven't looked into that yet. I need to remove my gauge cluster to fix this?
4) I really want to try that...

The thing is, inspection is due March 15th and I'm also throwing codes for the EGR, O2 sensor, catalytic converter low efficiency, vapor emission, and crank position sensor. That would mean I have to fix this oil light, replace the distributor, an O2 sensor, the cat, maybe do an EGR port cleaning. (I've seen write-ups that are good, I know) but I'm starting to hate this car regardless. Especially since I'm in college and am pressed for time.

Oh, and, TheGuy, yeah I've looked at them. I bought three Honda OEM filters from Majestic Honda (along with other things) and have been doing oil changes with those. Problem is consistent at least across two filters so far.