Blower motor and high oil pressure problem

[brainyass]

Problem 1:

On my 93 XJ 4.0 HO w/170K miles, it seems that my blower motor, on A/C, is running fine when I'm doing 60 MPH, but when I get close to 90-100 MPH (slow for Germany) it seems like it loses power and after a few seconds it blows out normally. This cycle continues on and on until I exit the Autoban. What could cause the blower to cycle? I did replace the control unit a couple of years earlier.

Problem 2:

My oil pressure is unusually high. About 6 years ago it went from 80 to 0 PSI and was hopping around like crazy. I pulled over expecting my engine to blow, but it was running fine. I replaced the oil pressure sending unit and after that it seemed to run higher. Nowadays, it stays about 70 PSI at idle and goes to 75-78 PSI at any speed. When I have been driving for 20 min or so, and am at a red light, it goes to 40 PSI. Then it goes back to 75 PSI when I start moving again. I'm thinking maybe it's another bad oil pressure sending unit (sensor) or maybe a blocked CCV (PVC) valve. Any pointers on the pressure problem would be much appreciated.

[JDPascal]

Problem #1 likely has to do with engine vacuum and the air flap switching between feet/vent and defrost positions. Low engine vacuum at higher speed is expected but a change up like described in the tsb at this website http://home.sc.rr.com/janet/TSB/24-01-96A.htm will reduce the flipping back and forth.


Problem #2 with the oil pressure doesn't "sound" like a problem at all but it should be checked with a mechanical gauge to varify the accuracy of your electric gauge.

My 5.2 sits at about 5 1/2 bar or about 65 psi when I first start up cold. It will fluctuate a little with RPM change when cold but after it warms up it will drop to around 40 psi at idle and upto 60 at cruising speeds (2000 rpm) Thats normal oil pressure operation.

JD

[brainyass]

As far as the oil pressure, the upper end of my gauge is 80 PSI. Before the sensor flipped out, the gauge would always be around 40 PSI.

[bmwilson]

My 4.0 high outputs run around 60 while my plain jane 4.0s run 40-45. these numbers seam to be the norm. Please inform if you find otherwise.