I was under my truck today and happened to look at the block. I noticed that just behind the oil filter there is a plug in the block. It's a thread in plug, not a freeze plug. Is that a coolant passage or is it for the oiling system? I would love to be able to add in a real oil pressure sender to the engine but there's not enough room to install something like a T for the factory pressure switch and a pressure sender. If that plug is for the oil system I could tap in to it there. Anyone have any idea what that plug is for?

 

Pretty sure that is the oil pressure sender that you're seeing. What "real oil pressure sender" do you want to add? If it ain't broke, don't try to fix.

 

Our engines don't have a real pressure sender. They have a switch. On at whatever PSI they are set for or off and your light comes on. The gauge in the cluster isn't a real gauge either. It comes up to about half and does not move. I would like to add in a real pressure gauge. One that actually tells you what the system pressure is.

 

What year is your truck?

 

2003 with the 4.7

 

Okay. See #2 in the image. That is your switch.

When mine acted up, I replaced it with a Mopar unit. I did check my pressure with an actual gauge. At idle, roughly 650-700 rpm, I was at 48 PSI (below 4 is low). At 3000 RPM, It was 90 PSI (I believe low is 25 psi).

Would be interesting to see how yours turns out. Are going with a digital or analog gauge? Post some pics when you get done.

 

Thanks. That's the issue though. I can't just remove the switch and replace it with a sender. I would constantly have a light on the dash. The computer needs the switch. I need to figure out a way to have both. That's why I was asking about the plug in the block. You can see the one I'm talking about just to the right of the switch in that picture.

 

I see what you're saying now. Why don't you pull the plug and see what flows out?


Edit: Found this on another site, to which I won't won't link here, for fear of mod retribution.

"You can use the top port above the oil filter for your new oil pressure gauge as it is a common port with the stock oil pressure switch location so that a tee is not required. The stock oil pressure switch location is 1/8 NPT and the two ports above the oil filter are 3/8 NPT. The bottom port is oil pump out pressure/oil pressure into the oil filter and the top port is oil filter out pressure. You want you new gauge connected to the top port (filter out pressure) so that if your filter has a restriction you can see the pressure loss."

So...it does sound like the port will work for you. Depending on your aftermarket sender's circumference you may need an extension to rise it up off the block, so it doesn't make contact with any protrusions.

 

i just used a T on my 2002 for the oil pressure sensor (yes sensor NOT switch) to put in a mechanical gauge. yes there is plenty of room for it

not sure what changed for 2003 but my 2002 had the NGC (4 plug PCM, or the newer setup which continued into 2003) and the oil pressure gauge was an actual gauge, it moved based on actual oil pressure and mimicked the mechanical gauge nicely (i put the mechanical gauge in because it stopped reading 0 when the engine was off, and i replaced the sensor a couple times before i gave up and put in a mechanical gauge)

 

I just checked the parts available and I am amazed to see you have a sender. I thought all manufacturers changed over to the switch in the 90s. Anyway I have a single pin connector switch. My luck.