dtpmike

I made 2 runs(to and from work), one this morning and one at night. About one week ago all the sudden my Oil pressure gauge read lower than normal.

It idled at 25 psi and ran warm at 30 psi.
Now idles at 15 psi and runs warm at 24 psi or so...

Just changed the oil a week ago and level is ok and its still golden color.

This morning I ran a winaldl. Look at my knocks.

http://ww2.cs.fsu.edu/~carollo/logs/...ning_KNOCK.txt
http://ww2.cs.fsu.edu/~carollo/logs/...orning_LOG.txt

Then later at night I made another run. My knocks increased a lot!

http://ww2.cs.fsu.edu/~carollo/logs/...ight_KNOCK.txt
http://ww2.cs.fsu.edu/~carollo/logs/..._Night_LOG.txt


Here is a run from February. Low knock counts as you can see.

http://ww2.cs.fsu.edu/~carollo/logs/2-9-04_KNOCK.txt
http://ww2.cs.fsu.edu/~carollo/logs/2-9-04_LOG.txt


What do you gather from this? Could it be that my knock counter is broken and my oil pressure sending unit is losing it?

BTW the engine does not really sound any different than it ever has.

89gta383

iTrader: (5)

How many miles on the motor? You changed the oil last week, and the knock and lower pressure started last week?

What weight oil was in it before, and what did you refill it with?

dtpmike

120,000 on motor.

It had 10W40 in it. All the sudden it dropped in pressure one day unexpectedly and so I changed the oil and filter, although I did put 10W30 in it this time. I did not see much difference in pressure before and after oil change.

dimented24x7

iTrader: (2)

Dont see much unusual in the datalogs. The knocks a bit high, especially considering that those numbers are really knock counts/256 but on an old motor it may just have some carbon build up or maybe there is mechanical noise thats triggering the knock sensor.

First, pick up a mechanical gauge and verify what the actual pressure is. 15 psi at idle doesnt sound too bad, though.

dtpmike

Just replaced the oil pressure sending unit and I think that fixed the oil pressure problem, but what should I do to get my knocks down? I already use premium gas.

dimented24x7

iTrader: (2)

Could try retarding the timing one-two degrees. Some sort of cleaner for the top end or even jsut water can help get alot of the combusion deposits out of the chambers.