Hey guys, I have a question. Yesterday I was heading to a MX track for some riding. Well, after about 30kms I slowed down to a gas station. I noticed the oil light came on, then OIL PRESSURE dropped to nothing...then when i give it some gas it comes back up. I checked under valve covers, i seen oil, checked oil level, all perfect. Is this just my oil pressure sending unit giving me heart attacks or what?

Thanks
Brad

 

When I was having some issues with the oil pressure fluctuating I started asking a lot of questions in here. After doing the research I was going to put a new oil pump in as well. One of the guys steered me in the direction of not paying attention to my dummy gauge inside the truck and talk me into installing a mechanical gauges because they're more accurate.

Before I installed my new oil pump the mechanical gauge was reading the oil pressure at 10psi at idle and it went as high as 20,30psi at normal driving speeds. My dashboard gauge was never the same readings and never got above 40? Even with a new oil pressure sensor switch.


So I ended up installing a standard oil pump. At idle speeds I'm around 35 to 40 psi and cruising speeds it is 65 and as high as 78 on a mechanical gauge. In my case I think my old pump was just worn out. I spent a lot of time cleaning everything and making sure the pickup screen was perfectly cleaned before reinstalling.

 

Yes that should be the first place to start and is the most inexpensive and easy route to take.

Put in a new oil pressure sending unit (located on the pass side of the block next to the dist cap) this should cost you about $20 for the sending unit. Some deep sockets will not reach it...you may to get a special oil pressure sending unit socket available at Napa for $10 it is 1 1/16 size.

If that does not work, your screen may be getting clogged and/or the oil pump is going out. You can never go wrong with putting in a good mechanical gauge over our factory dummy gauge... let us know how it works out for ya!

 

+1 .... try the sending unit first, and btw, the socket is not a regular oil pressure sending unit socket(even the deep one a parts store may have in stock will not work). Just make sure you try it on the sensor before you buy it.

 

I had the same thing happen on my out cross country and, what the cause of that was, bad sending unit. What you can do is lightly tap on it with an open ended wrench and remove the connector, rotate the contacts and try that. Mine came up well over 40 psi to where, it kept falling lower and lower the longer I was driving to the point of, requiring me to pull off the highway and shut the motor off in fear of having lost the pump.

CM

 

Anyone have a P/N for the correct socket to remove the SU by chance?

CM

 

Normally, under normal operation conditions, the pressure is to remain close to 40-50 by design. To prevent blow-out of the oil filter and seals at high RMPs, there, by design, is a pressure relief mechanism that handles that so that the pressure returns to normal range.

IF the pressure is in excess of 50 psi / 65-78 psi, that may indicate a problem with the relief mechanism or, the oil filter may be of the wrong type. In both cases, low or high pressure, it's not good. It should balance out under loading conditions and cruising conditions as well with a slight drop at idle when hot.

CM

 

x2. my new pumps and sending unit is the same. cold start idle 65-70psi, warm idle 35-40psi and cruising its at 60-70. psi should come up as rpm's increase. sbm uses a high pressure(70psi) pump not high volume and shouldnt be confused with high pressure.

 

Lisle 13250 or KD 3458

 

Hey guys...pressur has not dropped to zero anymore but it seems as it heats up maybe it drops some. Can someone tell me where exactly or have a picture of the oil pressure gauge sending unit? What about changing the oil pump if need be, fairly straight forward?

Thanks
Brad