I put air to this one and it was tripping around 5psi. It's hard to tell on a 0-100psi gauge though. It was very low and I can't believe they consider even below 10 acceptable. I freak out if anything with a gauge gets below 20psi. I love my chevy that runs 80psi and drops to 60 about the time the fans kick on.
The lash adjuster ticking went away so hopefully that puts an end to the misfire codes. I'll keep updating as results come in.

 

I have discussed this issue with a very car-savvy friend at work several times since purchasing the car. We have a factory oil pressure spec of 6psi on a normal engine. We know we have oil flow through the system (splashers in the rockers working when we pull the filler cap). We know that we have an adequate supply of oil in the engine. Oil pressure is a function of the restriction of flow through the engine. It's a fair assumption that the primary feed coming off the pump goes straight to the main bearings. We have the other post here that discussed having within-spec bearing clearances on an engine that was displaying the blinking oil light, (cured by installing a new oil pump) which anecdotally confirms that even at the low pressure that the mains are getting a lubricating film of oil sufficient to prevent excessive wear. In my case, I am not hearing any noises that I would associate with a loose bottom end in an engine that is either excessively worn or suffering from oiling issues.

If we assume that the aftermarket sending units are targeted at a trip value of 5psi, that's 17% lower than the factory spec on a new-ish engine---at the lowest pressure-generating circumstance our cars operate at, sitting at idle, in gear when the engine is up to full operating temperature. Then we could factor in what the manufacturing tolerance error on the sending units could be; errors of 5% to 10%? Less? And what would be a reasonable expectation of oil pressure loss on an engine that is 16 years old and has in excess of 100,000 miles on it?

I'm getting less inclined that this is a major issue on an engine that has 147,000 miles on it. At the next oil change I may get an oil pressure testing unit and hook it up to see what the pressures are and also source a genuine Mopar replacement sender. If the numbers are close enough to what I'd consider reasonable when weighing all these factors in, I'll be more than happy to let it go and live with a blinky light.

I appreciate the tenacity that you have shown in trying to figure this issue out; in another life, I might have done the same. ;-)

 

I'm just not a fan of being left on the side of the road because I ignored what could have been a very major problem. Both low oil pressure and misfire codes can leave the engine in an unrepairable mess quickly(after factoring in the price of repair vs. scrapping).
I decided that adding a permanent mechanical gauge would be better than that light. Then I can at least disconnect the oil pressure light and maybe get in a habbit of looking at the oil pressure monthly. Of course a gauge worth trusting is going to run way more than what I have spent in repairs.

I will agree with what you have stated and will be washing my hands of this problem. So far I am calling it quits on one of my other vehicles and this one is not far behind. It's time to just start selling and keep any eye out for something a little newer that I have more confidence in. Like I've said before, I'm very impressed with this engine considering what it has been through. Apparently the lubrication system leaves a bit to be desired if this is a common issue and is usually 'fixed' by replacing the sending unit.

This only confirms my opinion of Dodge... they either work great without a flaw or they are troubled forever once they do have a problem. My parents had an Intrepid that was perfect for almost 20 years, then developed a transmission problem and they were fighting all sorts of problems after that until the day it got totaled.

I'm sure I'll be on this board for a little while longer but I hope my days in this thread are done.

 

Car was up to it's antics again. After a good amount of in town driving it was doing the 750-500rpm drop when stopped at a light. During this time the oil light is on. If I keep one foot on the brake and give it a little gas, the RPM will dip and pick up quickly. So, this confirms that the oil pressure is in fact low. The low pressure lets the lifters bleed down reducing air inlet and making the AFR go rich. The rich condition causes the drop in engine speed, further reducing oil pressure. If this continues, the PCM will lean out the AFR at idle. In the past this does not seem to reduce the low RPM idle but does make the hesitation less noticable once the engine is given more air/fuel.

There is a pressure leak somewhere and I really need to find it. If the only symptom was the light being on then I could live with that but if drivability is also a factor, I can't really sit on the sideline with this one. I am happy that I can confidently limit the pressure loss to the top end. One possibility that scares me is that it could be a head gasket since the oil pressure has to go through the gasket in order to get to the cams.
This might be something I really need to stop at the dealer if they are willing to let me bounce ideas off a tech.

 

I can't stand this. Now the timing belt is loose and slipping on the water pump. It's nice when smoke comes off the timing belt. It doesn't seem like it's skipped... yet. If I follow the bolt torque specs this is what happens. I sure hope all the other bolts don't start causing problems.
Still no misfire codes which is a plus.

 

Timing belt is set correctly but I'm still getting the burning rubber smell. I'm going to stop in to the local Mitsubishi dealer today and see what they can tell me as far as the low oil pressure. So far I'm thinking it might be a leak in the headgasket where the oil passes from the block to the head... one or both of them. Besides that I can't think of another place where it can lose enough pressure for a pump that is within spec to not supply enough to maintain the minimum pressure.

 

I stopped in the Dodge dealer and they pretty much just said they would have to have a tech look at it. Of course, but to the tune of way more than I have and far more than the car is worth.
Next stop is the Mitsubishi dealer. I'm sure I'll get the same answer there as well though. No one that works on commision is going to take the time to help me fix my own stuff. So I either face the music or just tear it apart and see what I find.
Maybe I'll hit the lottery and I'll be able to buy a new car and dive into this one and figure out what the exact problem is. At this point I have so much time and effort wrapped up in it that it would haunt me if I gave up on it.

 

Again, I admire your dogged determination to figure it out. I'm not sure that I would go to the lengths you have.. That said, for the little that I've driven ours, I haven't seen the light flickering nearly as much since I dropped the quart of Lucas Oil Stabilizer in it. But it's such a fickle problem on ours that it's hardly conclusive that it's really having any effect on it either.

I'm still working on the transmission issue with the harsh 4-3 downshift and banging into gear moving from Neutral into Drive. At least the new solenoid pack seems to have fixed the other major issue. I took it to a tranny shop for a Quick Learn on the the TCM and was told that there was no signal from the input speed sensor and they couldn't do the Quick Learn. Changed out the sensor (after checking the wiring!) and the occasional harsh 2-1 downshift seems to be gone. Maybe getting the Quick Learn done will finally fix it.

 

I've been through a bunch of stuff looking for the burning rubber smell and smoke. At this point the wife left the car on the other side of town because it got so bad. Going to pick it up and I'm starting to think it's the rear valve cover gasket leaking. If not, it's going into the shop to at least get that fixed. I don't have time to waste on this POS anymore.
Speaking of, those valve covers are a joke as far as getting them to seal after replacement.

 

Found the smell, it was the rear valve cover leaking. I guess the torque spec of 31in-lb pretty much smashes the cover where the bolts are and it no longer seals. So, instead of buying the $100 valve cover I did the best I could to straighten it, did some modifying to the gasket and also used some RTV when I put it back together.
Not sure if I should keep thinking about the oil pressure light or not but I think I'm done with it for this year. I'll be back in the spring and maybe I'll pick up where I left off.